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Sample records for hard-solid lubricant coating

  1. Lubricant Coating Process

    NASA Technical Reports Server (NTRS)

    1989-01-01

    "Peen Plating," a NASA developed process for applying molybdenum disulfide, is the key element of Techniblast Co.'s SURFGUARD process for applying high strength solid lubricants. The process requires two machines -- one for cleaning and one for coating. The cleaning step allows the coating to be bonded directly to the substrate to provide a better "anchor." The coating machine applies a half a micron thick coating. Then, a blast gun, using various pressures to vary peening intensities for different applications, fires high velocity "media" -- peening hammers -- ranging from plastic pellets to steel shot. Techniblast was assisted by Rural Enterprises, Inc. Coating service can be performed at either Techniblast's or a customer's facility.

  2. Coatings for wear and lubrication

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1978-01-01

    Recent advances in the tribological uses of rf-sputtered and ion plated films of solid film lubricants (laminar solids, soft metals, organic polymers) and wear resistant refractory compounds (carbides, nitrides, silicides) are reviewed. The sputtering and ion plating potentials and the corresponding coatings formed were evaluated relative to the friction coefficient, wear endurance life and mechanical properties. The tribological and mechanical properties for each kind of film are discussed in terms of film adherence, coherence, density, grain size, morphology, internal stresses, thickness, and substrate conditions such as temperature, topography, chemistry and dc-biasing. The ion plated metallic films in addition to improved tribological properties also have better mechanical properties such as tensile strength and fatigue life.

  3. High-Temperature Solid Lubricant Coating

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Edmonds, Brian J.

    2010-01-01

    NASA PS400 is a solid lubricant coating invented for high-temperature tribological applications. This plasma-sprayed coating is a variant of the previously patented PS304 coating, and has been formulated to provide higher density, smoother surface finish, and better dimensional stability. This innovation is a new composite material that provides a means to reduce friction and wear in mechanical components. PS400 is a blend of a nickel-molybdenum binder, chrome oxide hardener, silver lubricant, and barium fluoride/calcium fluoride eutectic lubricant that can either be sprayed or deposited by other means, such as powder metallurgy. The resulting composite material is then finished by grinding and polishing to produce a smooth, self-lubricating surface.

  4. Plasma-sprayed self-lubricating coatings

    NASA Technical Reports Server (NTRS)

    Nakamura, H. H.; Logan, W. R.; Harada, Y.

    1982-01-01

    One of the most important criterion for acceptable commercial application of a multiple phase composition is uniformity and reproducibility. This means that the performance characteristics of the coat - e.g., its lubricating properties, bond strength to the substrate, and thermal properties - can be readily predicted to give a desired performance. The improvement of uniformity and reproducibility of the coats, the oxidation behavior at three temperature ranges, the effect of bond coat and the effect of preheat treatment as measured by adhesive strength tests, coating examination procedures, and physical property measurements were studied. The following modifications improved the uniformity and reproducibility: (1) changes and closer control in the particle size range of the raw materials used, (2) increasing the binder content from 3.2% to 4.1% (dried weight), and (3) analytical processing procedures using step by step checking to assure consistency.

  5. Fluoride coatings make effective lubricants in molten sodium environment

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Coating bearing surfaces with calcium fluoride-barium fluoride film provides effective lubrication against sliding friction in molten sodium and other severe environments at high and low temperatures.

  6. Self-lubricating coatings for high-temperature applications

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1990-01-01

    Solid lubricants with maximum temperature capabilities of about 1100 C are known. Unfortunately, none of the solid lubricants with the highest temperature capabilities are effective below 400 C. However, research at NASA's Lewis Research Center shows that silver and stable fluorides such as calcium and barium fluorides act synergistically to provide lubrication from below room temperature to about 900 C. This paper describes plasma-sprayed composite coatings that contain these solid lubricants in combination with a metal-bonded chromium carbide. The lubricants control friction, and the carbide matrix provides wear resistance. Successful tests of these coatings as backup lubricants for compliant gas bearings in turbomachinery and as self-lubricating liners in a four-cylinder Stirling engine are discussed.

  7. Lubrication by Diamond and Diamondlike Carbon Coatings

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1997-01-01

    Regardless of environment (ultrahigh vacuum, humid air, dry nitrogen, or water), ion-beam-deposited diamondlike carbon (DLC) and nitrogen-ion-implanted, chemical-vapor-deposited (CVD) diamond films had low steady-state coefficients of friction (less than 0.1) and low wear rates (less than or equal to 10(exp -6)cu mm/N(dot)m). These films can be used as effective wear-resistant, self-lubricating coatings regardless of environment. On the other hand, as-deposited, fine-grain CVD diamond films; polished, coarse-grain CVD diamond films; and polished and then fluorinated, coarse-grain CVD diamond films can be used as effective wear-resistant, self-lubricating coatings in humid air, in dry nitrogen, and in water, but they had a high coefficient of friction and a high wear rate in ultrahigh vacuum. The polished, coarse-grain CVD diamond film revealed an extremely low wear rate, far less than 10(exp 10) cu mm/N(dot)m, in water.

  8. Water Lubrication of Stainless Steel using Reduced Graphene Oxide Coating

    PubMed Central

    Kim, Hae-Jin; Kim, Dae-Eun

    2015-01-01

    Lubrication of mechanical systems using water instead of conventional oil lubricants is extremely attractive from the view of resource conservation and environmental protection. However, insufficient film thickness of water due to low viscosity and chemical reaction of water with metallic materials have been a great obstacle in utilization of water as an effective lubricant. Herein, the friction between a 440 C stainless steel (SS) ball and a 440 C stainless steel (SS) plate in water lubrication could be reduced by as much as 6-times by coating the ball with reduced graphene oxide (rGO). The friction coefficient with rGO coated ball in water lubrication was comparable to the value obtained with the uncoated ball in oil lubrication. Moreover, the wear rate of the SS plate slid against the rGO coated ball in water lubrication was 3-times lower than that of the SS plate slid against the uncoated ball in oil lubrication. These results clearly demonstrated that water can be effectively utilized as a lubricant instead of oil to lower the friction and wear of SS components by coating one side with rGO. Implementation of this technology in mechanical systems is expected to aid in significant reduction of environmental pollution caused by the extensive use of oil lubricants. PMID:26593645

  9. Self-lubricating coatings for high-temperature applications

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1987-01-01

    Some present-day aeropropulsion systems impose severe demands on the thermal and oxidative stability of lubricant, bearing, and seal materials. These demands will be much more severe for operational systems around the turn of the century. Solid lubricants with maximum temperature capabilities of about 1100 C are known. Unfortunately, none of the solid lubricants with the highest temperature capabilities are effective below approximately 400 C. However, research shows that silver and stable fluorides, such as calcium and barium fluoride act synergistically to provide lubrication from below room temperature to approximately 900 C. Plasma-sprayed, self-lubricating composite coatings that were developed at Lewis are described. Background information is given on coatings, designed as PS100 and PS101, that contain the solid lubricants in a Nichrome matrix. These coatings have low friction coefficients over a wide temperature range, but they have inadequate wear resistance for some long-duration applications. Wear resistance was dramatically improved in a recently developed coating PS200, by replacing the Nichrome matrix material with metal-bonded chromium carbide containing dispersed silver and calcium fluoride/barium fluoride eutectic (CaF2/BaF2). The lubricants control friction and the carbide matrix provides excellent wear resistance. Successful tests of these coatings are discussed.

  10. Anti-icing coating with an aqueous lubricating layer.

    PubMed

    Dou, Renmei; Chen, Jing; Zhang, Yifan; Wang, Xupeng; Cui, Dapeng; Song, Yanlin; Jiang, Lei; Wang, Jianjun

    2014-05-28

    In this paper, an anti-icing coating with an aqueous lubricating layer is reported. This anti-icing coating can be directly applied to various substrates, and the ice adhesion strength on the coated surfaces can be lowered greatly as compared to uncoated substrates. We demonstrate for the first time that the formed ice on this anti-icing coating can be blown off by a wind action in the wind tunnel with a controlled temperature and wind velocity. Moreover, the low ice adhesion of the anti-icing coating can be maintained even when the temperature is lowered to -53 °C. The robustness and durability of the anti-icing coating are proved by the icing/de-icing experiments. The results show that the anti-icing coating with an aqueous lubricating layer is of great promise for practical applications.

  11. Tribological Properties of CrN Coating Under Lubrication Conditions

    NASA Astrophysics Data System (ADS)

    Lubas, Janusz

    2012-08-01

    The paper presents research results of the influence of CrN coating on the friction parameters in friction pairs under lubricated friction conditions. The formed CrN homogeneous coating and CrN-steel 46Cr2 "ring" structure coating was matched under test conditions with a counterpart made from SAE-48 and SAE-783 bearing alloys. Tested sliding pairs were lubricated with 5W/40 Lotos synthetic engine oil. The tribological test was conducted on block-on-ring tester. The applied modification technologies of the surface layer of steel allowed for obtaining construction materials with pre-determined tribological characteristics required for the elements of friction pairs in lubricated contact. The results of the tests proved the possibility of implementing CrN coating in friction pairs, which work under mixed friction conditions. The results showed differences in the wear of bearing alloy, as the effect of the interaction between the co-operating surface layers and of the physiochemical changes of their surfaces, induced by external forces. The smallest wear of the bearing alloy occurs during the cooperation with the nitrided layer, whereas the largest wear occurs during the cooperation with the homogenous CrN coating. The CrN coating-46Cr2 steel "ring structure" decreases friction resistance during the start-up of the sliding pair, as well as lowers the level of the friction force and temperature in the friction area during co-operation with SAE-783 bearing alloys.

  12. Vacuum tribological behaviour of self lubricant quasicrystalline composite coatings

    NASA Astrophysics Data System (ADS)

    Garcí de Blas, F. J.; Román, A.; de Miguel, C.; Longo, F.; Muelas, R.; Agüero, A.

    2003-09-01

    High temperature resistant self-lubricant coatings are needed in space vehicles for components that operate at high temperatures and/or under vacuum. Thick composite lubricant coatings containing quasicrystalline alloys (QC) as the hard phase for wear resistance, have been deposited by thermal spray. The coatings also comprise lubricating materials (silver and BaF2-CaF2 eutectic) and NiCr as the tough component. This paper describes the vacuum tribological properties of TH103, a coating belonging to this family, with excellent microstructural quality. The coating was deposited by HVOF and tested under vacuum on a pin-on-disc tribometer. Different loads, linear speeds and pin materials were studied. The pin scars and disc wear tracks were characterized by EDS-SEM. A minimum mean steady friction coefficient of 0.32 was obtained employing a X-750 Ni superalloy pin in vacuum conditions under 10 N load and 15 cm/s linear speed, showing moderate wear of the disc and low wear of the pin.

  13. Wide-temperature-spectrum self-lubricating coatings prepared by plasma spraying

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1979-01-01

    Self-lubricating, multicomponent coatings, which lubricate over a wide range of operating conditions, are described. The coatings were successfully applied by plasma-spraying mixed powders onto superalloy substrates. They were evaluated in friction and wear experiments, and in sliding contact bearing tests. These coatings are wear resistant by virtue of their self lubricating characteristics rather than because of extreme hardness; a further benefit is low friction. Experiments with simple pin on disk sliding specimens and oscillating plain cylindrical bearing tests were performed to evaluate the tribological properties of the coatings. It was shown that coatings of nichrome, glass and calcium fluoride are self-lubricating from about 500 to 900 C, but give high friction at the lower temperatures. The addition of silver to the coating composition improved the low temperature bearing properties and resulted in coatings which are self-lubricating from cryogenic temperatures to at least 870 C; they are therefore, wide temperature spectrum, self-lubricating compositions.

  14. Press chamber coating as external lubrication for high speed rotary presses: lubricant spray rate optimization.

    PubMed

    Jahn, T; Steffens, K-J

    2005-12-01

    Lubrication of the tooling (punches and dies) is necessary to produce tablets. The most commonly used lubricant is magnesium stearate. Adding and blending magnesium stearate to the tablet mass often has negative effects on the properties of the compressed tablets (e.g., decreasing the tensile strength of the tablet). To avoid these negative effects, external lubrication systems were developed. This study investigated the functionality and the influence of a new press chamber coating system called the PKB II. The major difference between the PKB II and previous systems is its ability to spray a mixture of powdered magnesium stearate and air directly onto the punches and dies which was determined to allow the running of the rotor at higher speeds. The data showed a clear correlation between the spray rate of the lubricant and the concentration of the magnesium stearate per tablet. The PKB II was designed to allow for adjustments, in order to optimize the spray rate, by using the ejection force. The concentration of magnesium stearate was reduced to approximately 0.04% per tablet, using the PKB II. Additionally, the most common negative effects, such as the decrease in tablet tensile strength, were avoided by using this system.

  15. Solid film lubricants and thermal control coatings flown aboard the EOIM-3 MDA sub-experiment

    SciTech Connect

    Murphy, T.J.; David, K.E.; Babel, H.W.

    1995-02-01

    Additional experimental data were desired to support the selection of candidate thermal control coatings and solid film lubricants for the McDonnell Douglas Aerospace (MDA) Space Station hardware. The third Evaluation of Oxygen Interactions With Materials Mission (EOIM-3) flight experiment presented an opportunity to study the effects of the low Earth orbit environment on thermal control coatings and solid film lubricants. MDA provided five solid film lubricants and two anodic thermal control coatings for EOIM-3. The lubricant sample set consisted of three solid film lubricants with organic binders one solid film lubricant with an inorganic binder, and one solid film lubricant with no binder. The anodize coating sample set consisted of undyed sulfuric acid anodize and cobalt sulfide dyed sulfuric acid anodize, each on two different substrate aluminum alloys. The organic and inorganic binders in the solid film lubricants experienced erosion, and the lubricating pigments experienced oxidation. MDA is continuing to assess the effect of exposure to the low Earth orbit environment on the life and friction properties of the lubricants. Results to date support the design practice of shielding solid film lubricants from the low Earth orbit environment. Post-flight optical property analysis of the anodized specimens indicated that there were limited contamination effects and some atomic oxygen and ultraviolet radiation effects. These effects appeared to be within the values predicted by simulated ground testing and analysis of these materials, and they were different for each coating and substrate.

  16. Solid film lubricants and thermal control coatings flown aboard the EOIM-3 MDA sub-experiment

    NASA Technical Reports Server (NTRS)

    Murphy, Taylor J.; David, Kaia E.; Babel, Hank W.

    1995-01-01

    Additional experimental data were desired to support the selection of candidate thermal control coatings and solid film lubricants for the McDonnell Douglas Aerospace (MDA) Space Station hardware. The third Evaluation of Oxygen Interactions With Materials Mission (EOIM-3) flight experiment presented an opportunity to study the effects of the low Earth orbit environment on thermal control coatings and solid film lubricants. MDA provided five solid film lubricants and two anodic thermal control coatings for EOIM-3. The lubricant sample set consisted of three solid film lubricants with organic binders one solid film lubricant with an inorganic binder, and one solid film lubricant with no binder. The anodize coating sample set consisted of undyed sulfuric acid anodize and cobalt sulfide dyed sulfuric acid anodize, each on two different substrate aluminum alloys. The organic and inorganic binders in the solid film lubricants experienced erosion, and the lubricating pigments experienced oxidation. MDA is continuing to assess the effect of exposure to the low Earth orbit environment on the life and friction properties of the lubricants. Results to date support the design practice of shielding solid film lubricants from the low Earth orbit environment. Post-flight optical property analysis of the anodized specimens indicated that there were limited contamination effects and some atomic oxygen and ultraviolet radiation effects. These effects appeared to be within the values predicted by simulated ground testing and analysis of these materials, and they were different for each coating and substrate.

  17. Process for producing a corrosion-resistant solid lubricant coating

    SciTech Connect

    Niederhaeuser, P.; Hintermann, H.E.; Maillat, M.

    1983-11-15

    A corrosion-resistant surface formed of a sulfide-forming metal, in particular nickel, is first subjected to an electric plasma in an atmosphere containing hydrogen sulfide to form an adherent sulfide on said surface. The sulfided surface is then exposed to simultaneous cathodic sputtering of at least one solid lubricant which is a chalcogen compound of layer structure, in particular MoS/sub 2/, and at least one hydrophobic solid polymer, in particular PTFE. The coating thus formed is a composite coating in which the particles of the chalcogen compound are coated by the polymer. When the surface of the part to be coated does not consist of a corrosion-resistant sulfide-forming metal, a layer of such a metal is first deposited by cathodic sputtering. The composite coating withstands a wet oxidizing atmosphere, contrary to a coating of MoS/sub 2/ alone, and the method is applicable to any mechanical part intended to rub on other surfaces, such as a watch balance wheel staff and ball or roller bearings.

  18. Plasma-sprayed metal-glass fluoride coatings for lubrication to 1170 K (1650 F)

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1974-01-01

    Plasma spray of Nichrome matrix composite contains dispersed glass for oxidation protection and calcium fluoride for lubrication. Coatings can be applied to bearing journals and bearing bores. Coating was easily machinable and had excellent bond strength on substrate metal.

  19. Robotic burnishing system for solid film lubricant coated parts

    SciTech Connect

    Fureigh, M.L.

    1986-05-01

    A robotic burnishing system in the Painting Department reduced the operation average standard hour content by 64% and maintains a good part-to-part quality level for a group of parts coated with solid film lubricant. Required to be safe and simple to operate, the system uses a small PUMA 260 robot to process coated axisymmetrical pieceparts. Special tooling and seven pairs of robotic fingers were designed and built to handle 24 different small pieceparts. Individual robotic programs were created for each part and stored on 5-1/4 in. floppy disks with backup copies in Numerical Control. The operators and the manufacturing department readily accepted the robotic system. Additional part geometries will be developed for robotic processing. 12 figs.

  20. Lubricative coatings of copper oxide for aerospace applications

    NASA Astrophysics Data System (ADS)

    Goto, Masahiro; Kasahara, Akira; Oishi, Tetsuo; Konishi, Youko; Tosa, Masahiro

    2003-08-01

    Lubricative coatings of copper oxide on a stainless-steel substrate were synthesized by a rf magnetron sputter deposition method with a different gas ratio of oxygen and argon in sputter plasma. The crystal structure of the coatings was analyzed with x-ray diffraction spectroscopy. The friction force of the coating films in atmospheric pressure and in an ultrahigh vacuum (UHV) was evaluated by a vacuum pin-on-disk tribometer with different ball probes. Friction coefficients (μ) as low as 0.03 and 0.05 for a stainless-steel ball were achieved in atmospheric pressure and in an UHV, respectively. A value of μ=0.04 was also realized for a silicon nitride ball both in atmospheric pressure and in an UHV. Surface energy was analyzed by a contact angle measuring method which reveals that the behavior of the frictional properties correspond with that of the surface energy. Since the coatings consist of oxide, they will be applicable to a low-frictional coating with resistance to oxidation for aerospace applications in a low Earth orbit environment.

  1. Wear-Resistant, Self-Lubricating Surfaces of Diamond Coatings

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1995-01-01

    In humid air and dry nitrogen, as-deposited, fine-grain diamond films and polished, coarse-grain diamond films have low steady-state coefficients of friction (less than 0.1) and low wear rates (less than or equal to 10(exp -6) mm(exp 3)/N-m). In an ultrahigh vacuum (10(exp -7) Pa), however, they have high steady-state coefficients of friction (greater than 0.6) and high wear rates (greater than or equal to 10(exp -4) mm(exp 3)/N-m). Therefore, the use of as-deposited, fine-grain and polished, coarse-grain diamond films as wear-resistant, self-lubricating coatings must be limited to normal air or gaseous environments such as dry nitrogen. On the other hand, carbon-ion-implanted, fine-grain diamond films and nitrogen-ion-implanted, coarse-grain diamond films have low steady-state coefficients of friction (less than 0.1) and low wear rates (less than or equal to 10(exp -6) mm(exp 3)/N-m) in all three environments. These films can be effectively used as wear-resistant, self-lubricating coatings in an ultrahigh vacuum as well as in normal air and dry nitrogen.

  2. Solid Lubricants and Coatings for Extreme Environments: State-of-the-Art Survey

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2007-01-01

    An investigation was conducted to survey anticipated requirements for solid lubricants in lunar and Martian environments, as well as the effects of these environments on lubricants and their performance and durability. The success of habitats and vehicles on the Moon and Mars, and ultimately, of the human exploration of and permanent human presence on the Moon and Mars, are critically dependent on the correct and reliable operation of many moving mechanical assemblies and tribological components. The coefficient of friction and lifetime of any lubricant generally vary with the environment, and lubricants have very different characteristics under different conditions. It is essential, therefore, to select the right lubrication technique and lubricant for each mechanical and tribological application. Several environmental factors are hazardous to performance integrity on the Moon and Mars. Potential threats common to both the Moon and Mars are low ambient temperatures, wide daily temperature swings (thermal cycling), solar flux, cosmic radiation, and large quantities of dust. The surface of Mars has the additional challenges of dust storms, winds, and a carbon dioxide atmosphere. Solid lubricants and coatings are needed for lunar and Martian applications, where liquid lubricants are ineffective and undesirable, and these lubricants must perform well in the extreme environments of the Moon, Mars, and space, as well as on Earth, where they will be assembled and tested. No solid lubricants and coatings and their systems currently exist or have been validated that meet these requirements, so new solid lubricants must be designed and validated for these applications.

  3. Fabrics coated with lubricated nanostructures display robust omniphobicity

    NASA Astrophysics Data System (ADS)

    Shillingford, Cicely; MacCallum, Noah; Wong, Tak-Sing; Kim, Philseok; Aizenberg, Joanna

    2014-01-01

    The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e.g., rain), and when exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. Herein we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings.

  4. Fabrics coated with lubricated nanostructures display robust omniphobicity

    DOE PAGESBeta

    Shillingford, Cicely; MacCallum, Noah; Wong, Tak -Sing; Kim, Philseok; Aizenberg, Joanna

    2013-12-11

    The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e.g., rain), and whenmore » exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. However we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings.« less

  5. Fabrics coated with lubricated nanostructures display robust omniphobicity

    SciTech Connect

    Shillingford, Cicely; MacCallum, Noah; Wong, Tak -Sing; Kim, Philseok; Aizenberg, Joanna

    2013-12-11

    The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e.g., rain), and when exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. However we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings.

  6. Fabrics coated with lubricated nanostructures display robust omniphobicity

    SciTech Connect

    Shillingford, C; MacCallum, N; Wong, TS; Kim, P; Aizenberg, J

    2013-12-11

    The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e. g., rain), and when exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. Herein we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings.

  7. Spacecraft materials guide. [including: encapsulants and conformal coatings; optical materials; lubrication; and, bonding and joining processes

    NASA Technical Reports Server (NTRS)

    Staugaitis, C. L. (Editor)

    1975-01-01

    Materials which have demonstrated their suitability for space application are summarized. Common, recurring problems in encapsulants and conformal coatings, optical materials, lubrication, and bonding and joining are noted. The subjects discussed include: low density and syntactic foams, electrical encapsulants; optical glasses, interference filter, mirrors; oils, greases, lamillar lubricants; and, soldering and brazing processes.

  8. Effectiveness of solid lubricant coatings for friction in hard vacuum (10-9 tor)

    NASA Technical Reports Server (NTRS)

    Verkin, B. I.; Lyubraskiy, I. M.; Udovenko, V. F.; Sentyurikhina, L. N.

    1974-01-01

    A study was made of the efficiency of solid lubricating coatings, based on MoS2 with various binders, during friction and under highvacuum conditions. Mass spectrometry was used for an analysis of the composition of the gas evolved from the coatings in the friction process. It is shown that the vacuum level, loading, and sliding velocity influence coating effectiveness. In the friction process the solid lubricant coatings yield characteristic decay products associated with the chemical nature of the binders. The mechanism of coating breakdown during friction is associated with the binder breakdown mechanism.

  9. Evaluation of PS 212 Coatings Under Boundary Lubrication Conditions with an Ester-based Oil to 300 C

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Loomis, William R.; Dellacorte, Christopher

    1994-01-01

    High friction and wear of turbine engine components occur during high temperature excursions above the oxidation threshold of the liquid lubricant. This paper reports on research to study the use of a high temperature self lubricating coating, PS 212 for back-up lubrication in the event of failure of the liquid lubricant. Pin on disk tests were performed under dry and boundary-lubricated conditions at disk temperatures up to 300 C. The liquid lubricant was a formulated polyol ester qualified under MIL L-23699. At test temperatures above the oil's thermal degradation level, the use of PS 212 reduced wear, providing a back-up lubricant effect.

  10. Status and New Directions for Solid Lubricant Coatings and Composite Materials

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1984-01-01

    At one time, solid lubricants were used almost entirely in aerospace applications. Today there is a pronounced trend to use them over a much broader range of applications. For example, self-lubricating polymer-based composites have displaced traditional oil-lubricated, metallic composites for many journal bearings and thrust washers in applications as diverse as earth-moving machinery and snow blowers to aircraft applications. For moderate temperatures below 200 C, glass filament-wound epoxy bearings with PTFE lubricating liners are usefl; for temperatures up to 350 C, graphite fiber reinforced polyimide bearing materials are finding applications. Advanced technology engines have severe lubrication and wear problems at temperatures beyond the capabilities of any of these lubricants. Here, self-lubricating ceramics and inorganic composites for use at 1000 C or higher are of interest. However, perhaps the most significant new direction for solid lubricant coatings and self-lubricating composites is their steadily increasing use in dry bearings for large volume, moderate temperature applications. This can be attributed to their simplicity of use (no supporting lubricant system needed), light weight, convenience, and general cost effectiveness.

  11. Development of a self-lubricating plasma sprayed coating for rolling/sliding contact wear

    NASA Astrophysics Data System (ADS)

    Niebuhr, David Vernon

    The friction and wear that occurs between wheel and rail exacts millions of dollars out of maintenance budgets each year. Standard lubrication practices have been found to be unreliable in effectively lubricating curved track sections. Consequently, a method of reducing cost and increasing rail life is of significance to the railroad industry. Through the use of self-lubricating materials and thermal spray technology a composite surface coating was developed. A 1080 steel coating provided a wear-resistant matrix, in which to incorporate solid lubricants. The 1080 steel coating was found to provide increased wear resistance and some friction reduction (mu = 0.46 vs. mu = 0.5-0.7 for uncoated rail). The reduced wear stems from the coatings resistance to degenerate into severe wear modes. The wear rate of uncoated rail steel can be an order of magnitude greater than that of a 1080 steel coating. Three solid lubricant/steel coating systems were investigated; graphite incorporated into 1080 steel, copper incorporated into 1080 steel, and various polymers deposited over a 1080 steel coating. The structure of the coatings were evaluated by metallography and wear performance. Metallographic analysis included optical, SEM, and FIB. Polymer film analysis was performed with FTIR. Wear testing and friction measurement were accomplished with the Amsler twin disk wear testing machine. Coatings were tested against class C wheel steel at 5% and 35% slide/roll ratios, with contact pressures ranging from 700 to 1315 N/mmsp2. The work identified unique wear mechanisms for each coating system. The friction reduction and durability of the graphite/steel coatings was good at low slide/roll ratios. The copper/steel coatings were unable to control friction and had limited life. The polymer/steel coatings, particularly nylon/steel, had excellent performance at a wide range of slide/roll ratios and contact pressures. The nylon/1080 steel coatings were applied to rail sections for large

  12. A Review to the Laser Cladding of Self-Lubricating Composite Coatings

    NASA Astrophysics Data System (ADS)

    Quazi, M. M.; Fazal, M. A.; Haseeb, A. S. M. A.; Yusof, Farazila; Masjuki, H. H.; Arslan, A.

    2016-06-01

    Liquid lubricants are extremely viable in reducing wear damage and friction of mating components. However, due to the relentless pressure and the recent trend towards higher operating environments in advanced automotive and aerospace turbo-machineries, these lubricants cease to perform and hence, an alternate system is required for maintaining the self-lubricating environment. From the viewpoint of tribologist, wear is related to near-surface regions and hence, surface coatings are considered suitable for improving the functioning of tribo-pairs. Wear resistant coatings can be fabricated with the addition of various solid lubricants so as to reduce friction drag. In order to protect bulk substrates, self-lubricating wear resistant composite coatings have been fabricated by employing various surface coating techniques such as electrochemical process, physical and chemical vapor depositions, thermal and plasma spraying, laser cladding etc. Studies related to laser-based surface engineering approaches have remained vibrant and are recognized in altering the near surface regions. In this work, the latest developments in laser based self-lubricating composite coatings are highlighted. Furthermore, the effect of additives, laser processing parameters and their corresponding influence on mechanical and tribological performance is briefly reviewed.

  13. Evaluation of Advanced Solid Lubricant Coatings for Foil Air Bearings Operating at 25 and 500 C

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Fellenstein, James A.; Benoy, Patricia A.

    1998-01-01

    The tribological properties of one chrome oxide and one chrome carbide based solid lubricant coating were evaluated in a partial-arc foil bearing at 25 and 500 C. Start/stop bearing operation up to 20,000 cycles were run under 10 kPa (1.5 psi) static deadweight load. Bearing friction (torque) was measured during the test. Specimen wear and SEM/EDS surface analyses were conducted after testing to understand and elucidate the tribological characteristics observed. The chrome oxide coating which contains both (Ag) and (BaF2/CaF2) for low and high temperature lubrication, exhibited low friction in sliding against Al2O3 coated foils at 25 and 500 C. The chrome carbide coating, which lacked a low temperature lubricant but contained BaF2/CaF2 as a high temperature lubricant, exhibited high friction at 25 C and low friction at 500 C against both bare and Al2O3 coated superalloy foil surfaces. Post test surface analyses suggest that improved tribological performance is exhibited when a lubricant film from the coating transfers to the foil surface.

  14. High Temperature Solid Lubricant Coating for High Temperature Wear Applications

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher (Inventor); Edmonds, Brian J (Inventor)

    2014-01-01

    A self-lubricating, friction and wear reducing composite useful over a wide temperature range is described herein. The composite includes metal bonded chromium oxide dispersed in a metal binder having a substantial amount of nickel. The composite contains a fluoride of at least one Group I, Group II, or rare earth metal, and optionally a low temperature lubricant metal.

  15. Sputtered silver films to improve chromium carbide based solid lubricant coatings for use to 900 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.; Deadmore, Daniel L.

    1988-01-01

    Thin silver films, 250 to 3500 A thick, were sputtered onto PS200, a plasma sprayed, chromium carbide based solid lubricant coating, to reduce run-in wear and improve tribological properties. The coating contains bonded chromium carbide as the wear resistant base stock with silver and barium fluoride/calcium fluoride eutectic added as low and high temperature lubricants, respectively. Potential applications for the PS200 coating are cylinder wall/piston ring lubrication for Stirling engines and foil bearing journal lubrication. In this preliminary program, the silver film overlay thickness was optimized based on tests using a pin-on-disk tribometer. The friction and wear studies were performed in a helium atmosphere at temperatures from 25 to 760 C with a sliding velocity of 2.7 m/s under a 4.9 N load. Films between 1000 and 1500 A provide the best lubrication of the counterface material. The films enrich the sliding surface with lubricant and reduce the initial abrasiveness of the as ground, plasma-sprayed coating surface, thus reducing wear.

  16. Sputtered silver films to improve chromium carbide based solid lubricant coatings for use to 900 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.; Deadmore, Daniel L.

    1988-01-01

    Thin silver films, 250 to 3500 A thick, were sputtered onto PS200, a plasma sprayed, chromium carbide based solid lubricant coating, to reduce run-in wear and improve tribological properties. The coating contains bonded chromium carbide as the wear resistant base stock with silver and barium fluoride/calcium fluoride eutectic added as low and high temperature lubricants respectively. Potential applications for the PS200 coating are cylinder wall/piston ring lubrication for Stirling engines and foil bearing journal lubrication. In this preliminary program, the silver film overlay thickness was optimized based on tests using a pin-on-disk tribometer. The friction and wear studies were performed in a helium atmosphere at temperatures from 25 to 760 C with a sliding velocity of 2.7 m/s under a 4.9 N load. Films between 1000 and 1500 A provide the best lubrication of the counterface material. The films enrich the sliding surface with lubricant and reduce the initial abrasiveness of the as ground, plasma-sprayed coating surface, thus reducing wear.

  17. Tribological performance of NFC coatings under oil lubrication[Near Frictionless Carbon

    SciTech Connect

    Ajayi, O. O.; Alzoubi, M.; Erdemir, A.; Fenske, G. R.; Eryilmaz, O. L.; Zimmerman, S.

    2000-01-20

    An increase in engine and vehicle efficiency usually requires an increase in the severity of contact at the interfaces of many critical components. Examples of such components include piston rings and cylinder liners in the engine, gears in the transmission and axle, bearings, etc. These components are oil-lubricated and require enhancement of their tribological performance. Argonne National Laboratory (ANL) recently developed a carbon-based coating with very low friction and wear properties. These near-frictionless-carbon (NFC) coatings have potential for application in various engine components for performance enhancement. This paper presents the study of the tribological performance of NFC-coated steel surfaces when lubricated with fully formulated and basestock synthetic oils. The NFC coatings reduced both the friction and wear of lubricated steel surfaces. The effect of the coating was much more pronounced in tests with basestock oil. This suggests that NFC-coated parts may not require heavily formulated lubricant oils to perform satisfactorily in terms of reliability and durability.

  18. Commercialization of NASA PS304 Solid Lubricant Coating Enhanced by Fundamental Powder Flow Research

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm K.

    2003-01-01

    The NASA Glenn Research Center has developed a patented high-temperature solid lubricant coating, designated PS304, for reducing friction and wear in bearing systems. The material used to produce the coating is initially a blend of metallic and ceramic powders that are deposited on the bearing surface by the plasma spray process. PS304 was developed to lubricate foil air bearings in Oil-Free turbomachinery, where the moving surfaces are coated with a hydrodynamic air film except at the beginning and end of an operation cycle when the air film is not present. The coating has been successful in several applications including turbochargers, land-based turbines, and industrial drying furnace conveyor components, with current development activities directed at implementation in Oil-Free aeropropulsion engines.

  19. Lubricating Properties of Lead-Monoxide-Base Coatings of Various Compositions at Temperatures to 1250 F

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1959-01-01

    A number of ceramic coatings of different compositions containing lead monoxide (PbO) were studied to determine their relative merits as dry-film lubricants. Lead monoxide is known to be an effective solid lubricant at elevated temperatures, and this oxide was the main component in all compositions studied. Friction and wear properties were determined at temperatures from 750 to 1250 F, at a sliding velocity of 430 feet per minute, and at a normal load of 1 kilogram. In all of the coatings, PbO was the component primarily responsible for the lubricating properties. Oxides other than PbO had an indirect effect on lubrication by influencing such properties as adhesion, hardness, vitrifying or glaze-forming tendency, melting or softening point, and chemical stability of the coatings. Notable among these oxides were magnetite (Fe3O4.), which had generally a beneficial influence on ceramic- to-metal adhesion, and silica (SiO2), which inhibited the oxidation of PbO and enhanced the tendency for glaze formation on the sliding surfaces. Several of the compositions studied provided protection against metal-to-metal adhesive wear, galling, or seizure at test temperatures from 750 to 1250 F. Coating friction coefficients ranged from 0.20 to 0.37 at 75 F but were around 0.08 to 0.20 at temperatures of 1250 F.

  20. Lubricating Properties of Some Bonded Fluoride and Oxide Coatings for Temperature to 1500 F

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1960-01-01

    The lubricating properties of some experimental ceramic coatings, diffusion-bonded fluoride coatings, and ceramic-bonded fluoride coatings were determined. The experiments were conducted in an air atmosphere at a sliding velocity of 430 feet per minute and at temperatures from 75 to 1500 F. Several ceramic coatings provided substantial reductions in friction coefficient and rider wear (compared with the unlubricated metals). For example, a cobaltous oxide (CoO) base coating gave friction coefficients of 0.24 to 0.36 within the temperature range of 75 to 1400 F; serious galling and welding of the metal surfaces were prevented. The friction coefficients were higher than the arbitrary maximum (0.2) usually considered for effective boundary lubrication. However, when a moderately high friction coefficient can be tolerated, this type of coating may be a useful antiwear composition. Diffusion-bonded calcium fluoride (CaF2) on Haynes Stellite 21 and on Inconel X gave friction coefficients of 0.1 to 0.2 at 1500 F. Endurance life was dependent on the thermal history of the coating; life improved with increased exposure time at elevated temperatures prior to running. Promising results were obtained with ceramic-bonded CaF2 on Inconel X. Effective lubrication and good adherence were obtained with a 3 to 1 ratio of CaF2 to ceramic. A very thin sintered and burnished film of CaF2 applied to the surface of this coating further improved lubrication, particularly above 1350 F. The friction coefficient was 0.2 at 500 F and decreased with increasing temperature to 0.06-at 1500 F. It was 0.25 at 75 F and 0.22 at 250 F.

  1. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    SciTech Connect

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

    2007-01-30

    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 1013 to 1015 n/cm2. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 1015 to 1016 n/cm2 with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  2. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    NASA Astrophysics Data System (ADS)

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

    2007-01-01

    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 1013 to 1015 n/cm2. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 1015 to 1016 n/cm2 with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  3. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    NASA Technical Reports Server (NTRS)

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

    2007-01-01

    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 10(exp 13) to 10(exp 15) n per square centimeters. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 10(exp 15) to 10(exp 16) n per square centimeters with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  4. A new lubrication for high-density magnetic-coated disk

    NASA Astrophysics Data System (ADS)

    Hamada, M.; Fukushima, S.; Suenaga, T.; Itoh, K.; Ogawa, S.

    1984-03-01

    We have developed a new lubrication method to assure sufficient mechanical durability, which enabled us to produce low-noise, error-free magnetic-coated disks having a density as high as 30 000 FRPI. Improvement of SNR at high density requires reduction of alumina particles (the film hardening agent), and so the lubrication method is of great importance. So we first investigated the relationships between the film properties, head-to-disk adhesion, and the CSS (Contact Start & Stop) durability, and found that it was essential that the lubricant be absorbed into the film. For this purpose, we finally discovered a novel lubrication method, which is to put hydrophilic resin having an ether-bonded side chain as a component of the coating binder. By this method, the amount of absorbed lubricant increases with the resin content thus greatly improving durability. The resultant disk with a film thickness of 0.4 μm shows a durability of more than 100 000-CSS cycles, extremely low noise of 6 μV rms, and good bit-error characteristics at a density of 30 000 FRPI.

  5. Antifriction Property of Microarc Oxidation Coating on Titanium Alloy Under Solid Lubricating Sliding Condition

    NASA Astrophysics Data System (ADS)

    Wang, Y. M.; Jiang, B. L.; Guo, L. X.; Lei, T. Q.

    Ceramic coatings were fabricated on Ti6Al4V alloy surface by microarc oxidation (MAO) in Na2SiO3-(NaPO3)6-NaAlO2 solution using an AC power supply. Microstructure and phase composition of coating were characterized by SEM and XRD, respectively. The antifriction property of the coating with and without solid lubricant sliding against SAE 52100 steel ball was investigated on a pin-on-disk friction and wear tester. The results show that the microarc oxidation coating is relatively dense and uniform, mainly composed of rutile and anatase. The coating sliding against the steel has friction coefficient as low as 0.2-0.3 at an applied load of 0.5 N and sliding cycle below 2500, which is much smaller than that of uncoated Ti6Al4V against the same counterpart. The transferring of materials from the softer steel ball onto the coating surface is the main wear event, while the microarc oxidation coating is characterized by slight abrasive wear and adhesive wear. Introducing solid graphite lubricant into the porous surface of microarc oxidation coating significantly improves the long-term antifriction property (registering friction efficient of 0.15 in the long-term sliding) under a similar sliding condition. This improvement is attributed to the reduction of materials that are transferred from the softer steel ball onto the coating surface.

  6. Experimental evaluation of chromium-carbide-based solid lubricant coatings for use to 760 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher

    1987-01-01

    A research program is described which further developed and investigated chromium carbide based self-lubricating coatings for use to 760 C. A bonded chromium carbide was used as the base stock because of the known excellent wear resistance and the chemical stability of chromium carbide. Additives were silver and barium fluoride/calcium fluoride eutectic. The three coating components were blended in powder form, applied to stainless steel substrates by plasma spraying and then diamond ground to the desired coating thickness. A variety of coating compositions was tested to determine the coating composition which gave optimum tribological results. Coatings were tested in air, helium, and hydrogen at temperatures from 25 to 760 C. Several counterface materials were evaluated with the objective of discovering a satisfactory metal/coating sliding combination for potential applications, such as piston ring/cylinder liner couples for Stirling engines. In general, silver and fluoride additions to chromium carbide reduced the friction coefficient and increased the wear resistance relative to the unmodified coating. The lubricant additives acted synergistically in reducing friction and wear.

  7. Effects of nano-LaF3 on the friction and wear behaviors of PTFE-based bonded solid lubricating coatings under different lubrication conditions

    NASA Astrophysics Data System (ADS)

    Jia, Yulong; Wan, Hongqi; Chen, Lei; Zhou, Huidi; Chen, Jianmin

    2016-09-01

    Influence of nanometer lanthanum fluoride (nano-LaF3) on the tribological behaviors of polytetrafluoroethylene (PTFE) bonded solid lubricating coatings were investigated using a ring-on-block friction-wear tester under dry friction and RP-3 jet fuel lubrication conditions. The worn surfaces and transfer films formed on the counterpart steel rings were observed by scanning electron microscope (SEM) and optical microscope (OM), respectively. The microstructures of the nano-LaF3 modified coatings and the distribution states of nano-LaF3 were studied by field-emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM), respectively. The results show that incorporation of nano-LaF3 improves the microhardness and the friction-reduced and anti-wear abilities of PTFE bonded solid lubricating coatings. The wear life of the modified coating is about 6 times longer than that of the coating without nano-LaF3 filler at a relatively low applied load (200 N) and rotary speed (1000 rev/min) under dry friction condition. The friction coefficient and wear life of the modified coating decrease with increase of applied load under dry friction, but the friction coefficient has hardly any variation and wear life decreases under RP-3 jet fuel lubrication condition. In addition, the friction coefficient of the modified coating reduces with the rotary speed increasing under dry sliding but has little change under RP-3 lubrication, the wear life increases firstly and then decreases. The results indicated that the wear failure mechanism is dominated by applied load, which plays an important role in guidance of application of nano-LaF3 modified PTFE bonded coating under different working environment.

  8. Investigation of Thermal Processing on the Properties of PS304: A Solid Lubricant Coating

    NASA Technical Reports Server (NTRS)

    Benoy, Patricia A.; Williams, Syreeta (Technical Monitor)

    2002-01-01

    The effect of thermal processing on PS304, a solid lubricant coating, was investigated. PS304 is a plasma sprayed solid lubricant consisting of 10% Ag and 10% BaF2 and CaF2 in a eutectic mixture for low and high temperature lubricity respectively. In addition, PS304 contains 20% Cr2O3 for increased hardness and 60% NiCr which acts as a binder. All percents are in terms of weight not volume. Previous research on thermal processing (NAG3-2245) of PS304 revealed that substrate affected both the pre- and post-anneal hardness of the plasma spray coating. The objective of this grant was to both quantify this effect and determine whether the root cause was an artifact of the substrate or an actual difference in hardness due to interaction between the substrate and the coating. In addition to clarifying past research developments new data was sought in terms of coating growth due to annealing.

  9. The Effect of Composition on the Surface Finish of PS400: A New High Temperature Solid Lubricant Coating

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Stanford, malcolm K.; Thomas, Fransua; Edmonds, Brian J.

    2010-01-01

    A new composite, multi-constituent, solid lubricant coating, NASA PS400, developed for high temperature tribological applications, exhibits a smoother surface finish after grinding and polishing than its predecessors PS200 and PS300. In this paper, the baseline composition of PS400 is modified to investigate each individual constituent s role on the achievable surface finish through a series of coating deposition, grinding, and polishing experiments. Furthermore, to explore the limits of compositional tailoring for improved tribological performance, several PS400 coatings were doped with additional solid lubricants (graphite, MoS2 and BN) and tribologically tested. The test results clearly showed that, compared to PS300 coatings, PS400 achieves a smoother surface finish via a reduced lubricant content. Coatings prepared with higher than the baseline level (10 wt%) of lubricants exhibited higher final surface roughness than the earlier generation PS300 coatings. Reducing or eliminating the one or both lubricants (fluorides or silver) did not further improve the surface finish suggesting that the current composition of PS400 is near optimal with respect to surface finish. Lastly, attempts to improve the poor initial room temperature tribological behavior of PS400 via the addition of traditional solid lubricants were unsuccessful. Based upon this work and earlier results it is expected that future research will concentrate on developing methods to produce a lubricious glaze on the rubbing surface during break in to ensure that low friction and wear are rapidly achieved.

  10. Principles of ESCA and application to metal corrosion, coating and lubrication

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.

    1978-01-01

    The principles of ESCA (electron spectroscopy for chemical analysis) were described by comparison with other spectroscopic techniques. The advantages and disadvantages of ESCA as compared to other surface sensitive analytical techniques were evaluated. The use of ESCA was illustrated by actual applications to oxidation of steel and Rene 41, the chemistry of lubricant additives on steel, and the composition of sputter deposited hard coatings. A bibliography of material that was useful for further study of ESCA was presented and commented upon.

  11. Principles of ESCA and applications to metal corrosion, coating and lubrication. [Electron Spectroscopy for Chemical Analysis

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.

    1978-01-01

    The principles of ESCA (electron spectroscopy for chemical analysis) are described by comparison with other spectroscopic techniques. The advantages and disadvantages of ESCA as compared to other surface sensitive analytical techniques are evaluated. The use of ESCA is illustrated by actual applications to oxidation of steel and Rene 41, the chemistry of lubricant additives on steel, and the composition of sputter deposited hard coatings. Finally, a bibliography of material that is useful for further study of ESCA is presented and commented upon.

  12. New Generation of MoSx Based Solid Lubricant Coatings: Recent Developments and Applications

    SciTech Connect

    Haider, Julfikar; Hashmi, M. S. J.

    2011-01-17

    In recent times, there is a growing interest in applying Molybdenum disulphide (MoS{sub x}) solid lubricant coatings on components to improve the tribological performance (i.e. lower friction coefficient and wear rate). The tribological performance of MoS{sub x} coating is strongly dependent on coating properties and tribological environment. MoS{sub x} coatings are highly successful in certain applications such as in space/vacuum technology, but its effectiveness is questioned in other terrestrial applications such as in cutting tool industry due to its lower hardness and poor oxidation resistance leading to shorter life. In order to circumvent this drawback, the paper identifies that current research is being concentrated on developing MoS{sub x} based coatings using three different approaches: (1) Metal or compound addition in MoS{sub x} coating (2)MoS{sub x} layer on hard coating and (3)MoS{sub x} addition in hard coating matrix. Although the primary objective is same in all three cases, the third approach is considered to be more effective in improving the tribological properties of the coating. Finally, the potential applications of MoS{sub x} based coatings in different industrial sectors have been briefly outlined.

  13. The role of silver in self-lubricating coatings for use at extreme temperatures

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1985-01-01

    The advantages and disadvantages of elemental silver as a tribological material are discussed. It is demonstrated that the relatively high melting point of 961 deg C, softness, marked plasticity, and thermochemical stability of silver combine to make this metal useful in thin film solid lubricant coatings over a wide temperature range. Disadvantages of silver during sliding, except when used as a thin film, are shown to be gross ploughing due to plastic deformation under load with associated high friction and excessive transfer to counterface surfaces. This transfer generates an irregular surface topography with consequent undesirable changes in bearing clearance distribution. Research to overcome these disadvantages of element silver is described. A comparison is made of the tribological behavior of pure silver with that of silver formulated with other metals and high-temperature solid lubricants. The composite materials are prepared by co-depositing the powdered components with an airbrush followed by furnace heat treatment or by plasma-spraying. Composite coatings were formulated which are shown to be self-lubricating over repeated, temperature cycles from low temperature to about 900 deg C.

  14. Pulse electrodeposition of self-lubricating Ni-W/PTFE nanocomposite coatings on mild steel surface

    NASA Astrophysics Data System (ADS)

    Sangeetha, S.; Kalaignan, G. Paruthimal; Anthuvan, J. Tennis

    2015-12-01

    Ni-W/PTFE nanocomposite coatings with various contents of PTFE (polytetafluoroethylene) particles were prepared by pulse current (PC) electrodeposition from the Ni-W plating bath containing self lubricant PTFE particles to be co-deposited. Co-deposited PTFE particulates were uniformly distributed in the Ni-W alloy matrix. The coatings were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), X-ray Diffractometry (XRD) and Vicker's micro hardness tester. Tafel Polarization and electrochemical Impedance methods were used to evaluate the corrosion resistance behaviour of the nanocomposite coatings in 3.5% NaCl solution. It was found that, the Ni-W/PTFE nanocomposite coating has better corrosion resistance than the Ni-W alloy coating. Surface roughness and friction coefficient of the coated samples were assessed by Mitutoyo Surftest SJ-310 (ISO1997) and Scratch tester TR-101-M4 respectively. The contact angle (CA) of a water droplet on the surface of nanocomposite coating was measured by Optical Contact Goniometry (OCA 35). These results indicated that, the addition of PTFE in the Ni-W alloy matrix has resulted moderate microhardness, smooth surface, less friction coefficient, excellent water repellency and enhanced corrosion resistance of the nanocomposite coatings.

  15. Tribocharging phenomena in hard disk amorphous carbon coatings with and without perfluoropolyether lubricants

    SciTech Connect

    van den Oetelaar, Ronald J.A.; Xu, Lei; Ogletree, D. Frank; Salmeron, Miquel; Tang, Hung; Gui, Jing

    2000-08-01

    Scanning polarization force microscopy was used to study changes in surface potential (tribocharging) caused by the contact between a tungsten carbide tip and the amorphous carbon coating of a hard disk,both when bare and when covered with Zdol-TX lubricant. The surface potential change produced by tip contact decays with time at a rate that is strongly dependent on lubricant coverage, and on the presence of oxygen and water vapor in the environment. Two different charging mechanisms are proposed. One involves chemical modification of the surface by removal of oxygen bound to the surface. This gives rise to a potential change that decays with time. Another mechanism involves trapping of charge in states within the energy gap of the insulating carbon film. The potential change due to this trapped charge does not decay over periods much greater than 1 hour.

  16. Durable solid lubricant coatings for foil gas bearings to 315 deg C

    NASA Technical Reports Server (NTRS)

    Wagner, R. C.; Sliney, H. E.

    1984-01-01

    The durability and friction characteristics of bonded solid lubricant films on compliant gas bearings were measured. Coating compositions, which were judged to be suitable for use to at least 315 C, were selected for this study. Most of the data were obtained with polyimide-bonded graphite fluoride coatings and with silicate-bonded graphite coatings. These coatings were applied to the bore of Inconel 750 foil bearings. The journals were A286 stainless steel, with a rms surface finish of 0.2 microns. The foils were subjected to repeated start/stop cycles under a 14 kPa (2 psi) bearing unit load. Sliding contact occurred during lift-off and coast down at surface velocities less than 6 m/s (3000 rpm). Testing continued until 9000 cycles were accumulated or until a rise in starting torque indicated that the coating had failed. The coatings were evaluated in the temperature range from 25 C to 315 C. Comparisons in coating performance as well as discussions of their properties and methods of application are given.

  17. Start-stop testing of two self-acting air-lubricated spiral groove thrust bearing coatings

    NASA Technical Reports Server (NTRS)

    Dunfee, J. D.; Shapiro, W.

    1974-01-01

    Start-stop tests were conducted on air-lubricated spiral-groove thrust bearings. Application of a matrix-bonded molybdenum disulfide (MoS2) coating over a porous chrome oxide coating resulted in significantly lower friction, compared to bearings coated with chrome oxide only. The MoS2 coated bearing sustained 15,000 start-stop cycles at a maximum of 3600 rpm. Each cycle was 15 seconds on, 30 seconds off. The chrome oxide coated bearing failed by local welding after 2030 cycles. Both types of coatings exhibited early failures under higher thrust loads when operating films were insufficient to sustain the load without overheating.

  18. Lubricant-infused nanoparticulate coatings assembled by layer-by-layer deposition

    DOE PAGESBeta

    Sunny, Steffi; Vogel, Nicolas; Howell, Caitlin; Vu, Thy L.; Aizenberg, Joanna

    2014-09-01

    Omniphobic coatings are designed to repel a wide range of liquids without leaving stains on the surface. A practical coating should exhibit stable repellency, show no interference with color or transparency of the underlying substrate and, ideally, be deposited in a simple process on arbitrarily shaped surfaces. We use layer-by-layer (LbL) deposition of negatively charged silica nanoparticles and positively charged polyelectrolytes to create nanoscale surface structures that are further surface-functionalized with fluorinated silanes and infiltrated with fluorinated oil, forming a smooth, highly repellent coating on surfaces of different materials and shapes. We show that four or more LbL cycles introducemore » sufficient surface roughness to effectively immobilize the lubricant into the nanoporous coating and provide a stable liquid interface that repels water, low-surface-tension liquids and complex fluids. The absence of hierarchical structures and the small size of the silica nanoparticles enables complete transparency of the coating, with light transmittance exceeding that of normal glass. The coating is mechanically robust, maintains its repellency after exposure to continuous flow for several days and prevents adsorption of streptavidin as a model protein. As a result, the LbL process is conceptually simple, of low cost, environmentally benign, scalable, automatable and therefore may present an efficient synthetic route to non-fouling materials.« less

  19. Lubricant-infused nanoparticulate coatings assembled by layer-by-layer deposition

    SciTech Connect

    Sunny, Steffi; Vogel, Nicolas; Howell, Caitlin; Vu, Thy L.; Aizenberg, Joanna

    2014-09-01

    Omniphobic coatings are designed to repel a wide range of liquids without leaving stains on the surface. A practical coating should exhibit stable repellency, show no interference with color or transparency of the underlying substrate and, ideally, be deposited in a simple process on arbitrarily shaped surfaces. We use layer-by-layer (LbL) deposition of negatively charged silica nanoparticles and positively charged polyelectrolytes to create nanoscale surface structures that are further surface-functionalized with fluorinated silanes and infiltrated with fluorinated oil, forming a smooth, highly repellent coating on surfaces of different materials and shapes. We show that four or more LbL cycles introduce sufficient surface roughness to effectively immobilize the lubricant into the nanoporous coating and provide a stable liquid interface that repels water, low-surface-tension liquids and complex fluids. The absence of hierarchical structures and the small size of the silica nanoparticles enables complete transparency of the coating, with light transmittance exceeding that of normal glass. The coating is mechanically robust, maintains its repellency after exposure to continuous flow for several days and prevents adsorption of streptavidin as a model protein. As a result, the LbL process is conceptually simple, of low cost, environmentally benign, scalable, automatable and therefore may present an efficient synthetic route to non-fouling materials.

  20. Thermal Effects on a Low Cr Modification of PS304 Solid Lubricant Coating

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm K.; Yanke, Anne M.; DellaCorte, Christopher

    2004-01-01

    PS304 is a high temperature composite solid lubricant coating composed of Ni-Cr, Cr2O3, BaF2-CaF2 and Ag. The effect of reducing chromium content on the formation of voids in the Ni-Cr particles after heat treatment in PS304 coating was investigated. Coatings were prepared with Ni-20Cr or Ni-10Cr powder and in various combinations with the other constituents of PS304 (i.e., chromia, silver and eutectic BaF2-CaF2 powders) and deposited on metal substrates by plasma spray. Specimens were exposed to 650 C for 24 hr or 1090 C for 15 hr and then examined for changes in thickness, coating microstructure and adhesion strength. Specimens with Ni-10Cr generally had less thickness increase than specimens with Ni-20Cr, but there was great variance in the data. Reduction of chromium concentration in Ni-Cr powder tended to reduce the appearance of voids in the Ni-Cr phase after heat exposure. The presence of BaF2-CaF2 resulted in a significant increase in coating adhesion strength after heat treatment, while coatings without BaF2-CaF2 had no significant change. Chemical composition analysis suggested that the void formation was due to oxidation of chromium in the Ni-Cr constituent.

  1. Lubricant-Infused Nanoparticulate Coatings Assembled by Layer-by-Layer Deposition

    SciTech Connect

    Sunny, S; Vogel, N; Howell, C; Vu, TL; Aizenberg, J

    2014-09-01

    Omniphobic coatings are designed to repel a wide range of liquids without leaving stains on the surface. A practical coating should exhibit stable repellency, show no interference with color or transparency of the underlying substrate and, ideally, be deposited in a simple process on arbitrarily shaped surfaces. We use layer-by-layer (LbL) deposition of negatively charged silica nanoparticles and positively charged polyelectrolytes to create nanoscale surface structures that are further surface-functionalized with fluorinated silanes and infiltrated with fluorinated oil, forming a smooth, highly repellent coating on surfaces of different materials and shapes. We show that four or more LbL cycles introduce sufficient surface roughness to effectively immobilize the lubricant into the nanoporous coating and provide a stable liquid interface that repels water, low-surface-tension liquids and complex fluids. The absence of hierarchical structures and the small size of the silica nanoparticles enables complete transparency of the coating, with light transmittance exceeding that of normal glass. The coating is mechanically robust, maintains its repellency after exposure to continuous flow for several days and prevents adsorption of streptavidin as a model protein. The LbL process is conceptually simple, of low cost, environmentally benign, scalable, automatable and therefore may present an efficient synthetic route to non-fouling materials.

  2. Thermal Processing Effects on the Adhesive Strength of PS304 High Temperature Solid Lubricant Coatings

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Edmonds, Brian J.; Benoy, Patricia A.

    2001-01-01

    In this paper the effects of post deposition heat treatments on the cohesive and adhesive strength properties of PS304, a plasma sprayed nickel-chrome based, high temperature solid lubricant coating deposited on stainless steel, are studied. Plasma spray deposited coating samples were exposed in air at temperatures from 432 to 650 C for up to 500 hr to promote residual stress relief, enhance particle to particle bonding and increase coating to substrate bond strength. Coating pull-off strength was measured using a commercial adhesion tester that utilizes 13 mm diameter aluminum pull studs attached to the coating surface with epoxy. Pull off force was automatically recorded and converted to coating pull off strength. As deposited coating samples were also tested as a baseline. The as-deposited (untreated) samples either delaminated at the coating-substrate interface or failed internally (cohesive failure) at about 17 MPa. Samples heat treated at temperatures above 540 C for 100 hr or at 600 C or above for more than 24 hr exhibited strengths above 31 MPa, nearly a two fold increase. Coating failure occurred inside the body of the coating (cohesive failure) for nearly all of the heat-treated samples and only occasionally at the coating substrate interface (adhesive failure). Metallographic analyses of heat-treated coatings indicate that the Nickel-Chromium binder in the PS304 appears to have segregated into two phases, a high nickel matrix phase and a high chromium precipitated phase. Analysis of the precipitates indicates the presence of silicon, a constituent of a flow enhancing additive in the commercial NiCr powder. The exact nature and structure of the precipitate phase is not known. This microstructural change is believed to be partially responsible for the coating strength increase. Diffusion bonding between particles may also be playing a role. Increasing the heat treatment temperature, exposure time or both accelerate the heat treatment process. Preliminary

  3. Surface Design and Engineering Toward Wear-Resistant, Self-Lubricating Diamond Films and Coatings

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1999-01-01

    The tribological properties of chemical-vapor-deposited (CVD) diamond films vary with the environment, possessing a Jekyll-and-Hyde character. CVD diamond has low coefficient of friction and high wear resistance in air but high coefficient of friction and low wear resistance in vacuum. Improving the tribological functionality of materials (such as achieving low friction and good wear resistance) was an aim of this investigation. Three studies on the surface design, surface engineering, and tribology of CVD diamond have shown that its friction and wear are significantly reduced in ultrahigh vacuum. The main criteria for judging whether diamond films are an effective wear-resistant, self-lubricating material were coefficient of friction and wear rate, which must be less than 0.1 and on the order of 10(exp 6) cu mm/N(dot)m, respectively. In the first study the presence of a thin film (less than 1 micron thick) of amorphous, nondiamond carbon (hydrogenated carbon, also called diamondlike carbon or DLC) on CVD diamond greatly decreased the coefficient of friction and the wear rate. Therefore, a thin DLC film on CVD diamond can be an effective wear-resistant, lubricating coating in ultrahigh vacuum. In the second study the presence of an amorphous, nondiamond carbon surface layer formed on CVD diamond by ion implantation significantly reduced the coefficient of friction and the wear rate in ultrahigh vacuum. Therefore, such surface layers are acceptable for effective self-lubricating, wear-resistant applications of CVD diamond. In the third study CVD diamond in contact with cubic boron nitride exhibited low coefficient of friction in ultra high vacuum. Therefore, this materials combination can provide an effective self-lubricating, wear-resistant couple in ultrahigh vacuum.

  4. NASA PS400: A New Temperature Solid Lubricant Coating for High Temperature Wear Applications

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Edmonds, B. J.

    2009-01-01

    A new solid lubricant coating, NASA PS400, has been developed for high temperature tribological applications. This plasma sprayed coating is a variant of the patented PS304 coating and has been formulated to provide higher density, smoother surface finish and better dimensional stability than PS304. PS400 is comprised of a nickel-molybdenum binder that provides strength, creep resistance and extreme oxidative and dimensional stability. Chromium oxide, silver and barium-calcium fluoride eutectic are added to the binder to form PS400.Tribological properties were evaluated with a pin-on-disk test rig in sliding contact to 650 C. Coating material samples were exposed to air, argon and vacuum at 760 C followed by cross section microscopic analysis to assess microstructure stability. Oil-Free microturbine engine hot section foil bearing tests were undertaken to assess PS400 s suitability for hot foil gas bearing applications. The preliminary results indicate that PS400 exhibits tribological characteristics comparable to the PS304 coating but with enhanced creep resistance and dimensional stability suitable for demanding, dynamic applications.

  5. Tribological composition optimization of chromium-carbide-based solid lubricant coatings for foil gas bearings at temperatures to 650 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher

    1988-01-01

    The determination of the tribilogically optimum composition of chromium-carbide-based solid lubricant coatings using a foil gas bearing test apparatus is described. The coatings contain a wear resistant chromium carbide `base stock' with the lubricant additives silver and BaF2-CaF2 eutectic. The coating composition is optimized for air-lubricated foil gas bearings at temperatures ranging from 25 to 650 C. The various compositions were prepared by powder blending, then plasma sprayed onto Inconel 718 test journals and diamond ground to the desired coating thickness and surface finish. The journals were operated against preoxidized Ni-Cr alloy foils, and the test bearings were subjected to repeated start-stop cycles under a bearing unit of 14 kPa. Sliding contact between the coated journal and the smooth foil occurs during bearing start-up before lift-off or hydrodynamic lubrication by the air film and during bearing coast-down. The bearings were tested for 9000 start-stop cycles or until specimen reached a predetermined failure level.

  6. Investigation of Potential Thermal Processing Techniques for the Enhancement of PS300 High Temperature Solid Lubricant Coatings

    NASA Technical Reports Server (NTRS)

    Benoy, Patricia A.

    2000-01-01

    Contemporary trends in rotating machinery development have produced a continuous evolution towards ever increasing speeds and higher operating temperatures. This process has been particularly evident in aerospace and automotive applications such as turbochargers. The combination of high temperature and high speed has exceeded the capacity of mainstream liquid lubrication technology. The NASA Glenn Research Center has been at the forefront in developing innovative solid lubricants for the oil free protection of rotating machinery under these extreme environmental conditions. The most recent of these is the PS 300 series of plasma sprayed solid lubricant coatings. St Louis University and NASA Glenn Research Center entered into this cooperative agreement to investigate potential thermal processing techniques for the enhancement of the PS 304 solid lubricant.

  7. Investigating critical effects of variegated lubricants, glidants and hydrophilic additives on lag time of press coated ethylcellulose tablets.

    PubMed

    Patadia, Riddhish; Vora, Chintan; Mittal, Karan; Mashru, Rajashree

    2016-01-01

    The research envisaged focuses on vital impacts of variegated lubricants, glidants and hydrophilic additives on lag time of press coated ethylcellulose (EC) tablets using prednisone as a model drug. Several lubricants and glidants such as magnesium stearate, colloidal SiO2, sodium stearyl fumarate, talc, stearic acid, polyethylene glycol (6000) and glyceryl behenate were investigated to understand their effects on lag time by changing their concentrations in outer coat. Further, the effects of hydrophilic additives on lag time were examined for hydroxypropylmethylcellulose (E5), hydroxypropylcellulose (EF and SSL), povidone (K30), copovidone, polyethylene glycol (4000), lactose and mannitol. In vitro drug release testing revealed that each selected lubricant/glidant, if present even at concentration of 0.25% w/w, significantly reduced the lag time of press coated tablets. Specifically, colloidal SiO2 and/or magnesium stearate were detrimental while other lubricants/glidants were relatively less injurious. Among hydrophilic additives, freely water soluble fillers had utmost influence in lag time, whereas, comparatively less impact was observed with polymeric binders. Concisely, glidant and lubricant should be chosen to have minimal impact on lag time and further judicious selection of hydrophilic additives should be exercised for modulating lag time of pulsatile release formulations.

  8. Friction and Wear Characteristics of a Modified Composite Solid Lubricant Plasma Spray Coating

    NASA Technical Reports Server (NTRS)

    Stanford, M. K.; DellaCorte, C.

    2004-01-01

    LCR304 is a solid lubricant coating composed of Ni-10Cr, Cr2O3, BaF2-CaF2 and Ag and developed for dimensional stability in high temperature air. This coating is a modification of PS304, which differs in that the Ni-Cr constituent contains 20wt% Cr. The tribological characteristics of LCR304 were evaluated by pin-on-disk and foil air bearing rig testing from 25 to 650 C and compared to previous test results with PS304. For both tests, the friction coefficient decreased as temperature increased from 25 to 650 C. Wear generally decreased with increasing temperature for all pin-on-disk tests. LCR304 coated components produced the least wear of Inconel X-750 counterface materials at 427 and 650 C. These results indicate that the LCR304 coating has potential as a replacement for PS304 in, for example, low cycle (minimum wear) applications where dimensional stability is imperative.

  9. Complex frictional analysis of self-lubricant W-S-C/Cr coating.

    PubMed

    Polcar, Tomas; Gustavsson, Fredrik; Thersleff, Thomas; Jacobson, Staffan; Cavaleiro, Albano

    2012-01-01

    Transition metal dichalcogenides belong to one of the most developed classes of materials for solid lubrication. However, one of the main drawbacks of most of the self-lubricating coatings is their low load-bearing capacity, particularly in terrestrial atmospheres. In our previous work, alloying thin films based on tungsten disulfide with non-metallic interstitial elements, such as carbon or nitrogen, has been studied in order to improve tribological performance in different environments. Excellent results were reached with the deposited coatings hardness, in some cases, more than one order of magnitude higher than single W-S films. In this work, W-S-C films were deposited with increasing Cr contents by co-sputtering chromium and composite WS2-C and targets. Two films were prepared with approx. 7 and 13 at.% of Cr. Alloying with chromium led to dense films with amorphous microstructure; the hardness and adhesion was improved. Sliding tests were carried out in dry and humid air using a pin-on-disc tribometer with 100Cr6 steel balls as a counterpart. To analyse the sliding process, the surfaces in the contact were investigated by X-ray photoelectron spectroscopy (bonding), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Surface and sub-surface structural modification of the coating and composition of the transferred tribolayer are discussed in detail. High friction in humid air was attributed to the absence of a well-ordered WS2 sliding interface. On the other hand, the existence of such an interface explained the very low friction observed in dry air. PMID:23285640

  10. Complex frictional analysis of self-lubricant W-S-C/Cr coating.

    PubMed

    Polcar, Tomas; Gustavsson, Fredrik; Thersleff, Thomas; Jacobson, Staffan; Cavaleiro, Albano

    2012-01-01

    Transition metal dichalcogenides belong to one of the most developed classes of materials for solid lubrication. However, one of the main drawbacks of most of the self-lubricating coatings is their low load-bearing capacity, particularly in terrestrial atmospheres. In our previous work, alloying thin films based on tungsten disulfide with non-metallic interstitial elements, such as carbon or nitrogen, has been studied in order to improve tribological performance in different environments. Excellent results were reached with the deposited coatings hardness, in some cases, more than one order of magnitude higher than single W-S films. In this work, W-S-C films were deposited with increasing Cr contents by co-sputtering chromium and composite WS2-C and targets. Two films were prepared with approx. 7 and 13 at.% of Cr. Alloying with chromium led to dense films with amorphous microstructure; the hardness and adhesion was improved. Sliding tests were carried out in dry and humid air using a pin-on-disc tribometer with 100Cr6 steel balls as a counterpart. To analyse the sliding process, the surfaces in the contact were investigated by X-ray photoelectron spectroscopy (bonding), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Surface and sub-surface structural modification of the coating and composition of the transferred tribolayer are discussed in detail. High friction in humid air was attributed to the absence of a well-ordered WS2 sliding interface. On the other hand, the existence of such an interface explained the very low friction observed in dry air.

  11. Does the Use of Diamond-Like Carbon Coating and Organophosphate Lubricant Additive Together Cause Excessive Tribochemical Material Removal?

    SciTech Connect

    Zhou, Yan; Leonard, Donovan N.; Meyer, Harry M.; Luo, Huimin; Qu, Jun

    2015-08-22

    We observe unexpected wear increase on a steel surface that rubbed against diamond-like carbon (DLC) coatings only when lubricated by phosphate-based antiwear additives. Contrary to the literature hypothesis of a competition between zinc dialkyldithiophosphate produced tribofilms and DLC-induced carbon transfer, here a new wear mechanism based on carbon-catalyzed tribochemical interactions supported by surface characterization is proposed

  12. Experimental evaluation of chromium-carbide-based solid lubricant coatings for use to 760/sup 0/C

    SciTech Connect

    Della Corte, C.

    1987-08-01

    This paper describes a research program to further develop and investigate chromium carbide based self-lubricating coatings for use to 760/sup 0/C. A bonded chromium carbide was used as the ''base stock'' because of the known excellent wear resistance and the chemical stability of chromium carbide. ''Additives'' were silver and barium fluoride/calcium fluoride eutectic. The three coating components were blended in powder form, applied to stainless steel substrates by plasma-spraying and then diamond ground to the desired coating thickness. A variety of coating compositions was tested to determine the coating composition which gave optimum tribological results. Coatings were tested in air, helium, and hydrogen at temperatures from 25 to 760/sup 0/C. Several counterface materials were evaluated with the objective of discovering a satisfactory metal/coating sliding combination for potential applications, such as piston ring/cylinder liner couples for Stirling engines. In general, silver and fluoride additions to chromium carbide reduced the friction coefficient and increased the wear resistance relative to the unmodified coating. The lubricant ''additives'' acted synergistically in reducing friction and wear. Several coating compositions gave good results in hydrogen, helium, and air to 760/sup 0/C.

  13. Friction and wear behaviour of Mo-W doped carbon-based coating during boundary lubricated sliding

    NASA Astrophysics Data System (ADS)

    Hovsepian, Papken Eh.; Mandal, Paranjayee; Ehiasarian, Arutiun P.; Sáfrán, G.; Tietema, R.; Doerwald, D.

    2016-03-01

    A molybdenum and tungsten doped carbon-based coating (Mo-W-C) was developed in order to provide low friction in boundary lubricated sliding condition at ambient and at high temperature. The Mo-W-C coating showed the lowest friction coefficient among a number of commercially available state-of-the-art DLC coatings at ambient temperature. At elevated temperature (200 °C), Mo-W-C coating showed a significant reduction in friction coefficient with sliding distance in contrast to DLC coatings. Raman spectroscopy revealed the importance of combined Mo and W doping for achieving low friction at both ambient and high temperature. The significant decrease in friction and wear rate was attributed to the presence of graphitic carbon debris (from coating) and 'in situ' formed metal sulphides (WS2 and MoS2, where metals were supplied from coating and sulphur from engine oil) in the transfer layer.

  14. Diamond and diamondlike carbon as wear-resistant, self-lubricating coatings for silicon nitride

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1995-01-01

    Recent work on the friction and wear properties of as-deposited fine-grain diamond, polished coarse-grain diamond, and as-deposited diamondlike carbon (DLC) films in humid air at a relative humidity of approximately 40 percent and in dry nitrogen is reviewed. Two types of chemical vapor deposition (CVD) processes are used to deposit diamond films on silicon nitride (Si3N4) substrates: microwave-plasma and hot-filament. Ion beams are used to deposit DLC films of Si3N4 substrates. The diamond and DLC films in sliding contact with hemispherical bare Si3N4 pins have low steady-state coefficients of friction (less than 0.2) and low wear rates (less than 10(exp -7) mm(exp 2)/N-m), and thus, can be used effectively as wear-resistant, self-lubricating coatings for Si3N4 in the aforementioned two environments.

  15. Hydrodynamic air lubricated compliant surface bearing for an automotive gas turbine engine. 2: Materials and coatings

    NASA Technical Reports Server (NTRS)

    Bhushan, B.; Ruscitto, D.; Gray, S.

    1978-01-01

    Material coatings for an air-lubricated, compliant journal bearing for an automotive gas turbine engine were exposed to service test temperatures of 540 C or 650 C for 300 hours, and to 10 temperature cycles from room temperatures to the service test temperatures. Selected coatings were then put on journal and partial-arc foils and tested in start-stop cycle tests at 14 kPa (2 psi) loading for 2000 cycles. Half of the test cycles were performed at a test chamber service temperature of 540 C (1000 F) or 650 C (1200 F); the other half were performed at room temperature. Based on test results, the following combinations and their service temperature limitations are recommended: HL-800 TM (CdO and graphite) on foil versus chrome carbide on journal up to 370 C (700 F); NASA PS 120 (Tribaloy 400, silver and CaF2 on journal versus uncoated foil up to 540 C (1000 F); and Kaman DES on journal and foil up to 640 C (1200 F). Kaman DES coating system was further tested successfully at 35 kPa (5 psi) loading for 2000 start-stop cycles.

  16. Surface Design and Engineering Toward Wear-Resistant, Self-Lubricant Diamond Films and Coatings. Chapter 10

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1999-01-01

    This chapter describes three studies on the surface design, surface engineering, and tribology of chemical-vapor-deposited (CVD) diamond films and coatings toward wear-resistant, self-lubricating diamond films and coatings. Friction mechanisms and solid lubrication mechanisms of CVD diamond are stated. Effects of an amorphous hydrogenated carbon on CVD diamond, an amorphous, nondiamond carbon surface layer formed on CVD diamond by carbon and nitrogen ion implantation, and a materials combination of cubic boron nitride and CVD diamond on the adhesion, friction, and wear behaviors of CVD diamond in ultrahigh vacuum are described. How surface modification and the selected materials couple improved the tribological functionality of coatings, giving low coefficient of friction and good wear resistance, is explained.

  17. Preliminary Evaluation of PS300: A New Self-Lubricating High Temperature Composite Coating for Use to 800 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, C.; Edmonds, B. J.

    1995-01-01

    This paper introduces PS300, a plasma sprayed, self-lubricating composite coating for use in sliding contacts at temperatures to 800 C. PS300 is a metal bonded chrome oxide coating with silver and BaF2/CaF2 eutectic solid lubricant additives. PS300 is similar to PS200, a chromium carbide based coating, which is currently being investigated for a variety of tribological applications. In pin-on-disk testing up to 650 C, PS300 exhibited comparable friction and wear properties to PS200. The PS300 matrix, which is predominantly chromium oxide rather than chromium carbide, does not require diamond grinding and polishes readily with silicon carbide abrasives greatly reducing manufacturing costs compared to PS200. It is anticipated that PS300 has potential for sliding bearing and seal applications in both aerospace and general industry.

  18. Coated carbide drill performance under soluble coconut oil lubricant and nanoparticle enhanced MQL in drilling AISI P20

    NASA Astrophysics Data System (ADS)

    Jamil, N. A. M.; Azmi, A. I.; Fairuz, M. A.

    2016-02-01

    This research experimentally investigates the performance of a TiAlN coated carbide drill bit in drilling AISI P20 through two different kinds of lubricants, namely; soluble coconut oil (SCO) and nanoparticle-enhanced coconut oil (NECO) under minimum quantity lubrication system. The tool life and tool wear mechanism were studied using various cutting speeds of 50, 100 and 150 m/min with a constant feed of 0.01 mm/rev. Since the flank wear land was not regular along the cutting edge, the average flank wear (VB) was measured at several points using image analysis software. The drills were inspected using a scanning electron microscope to further elucidate the wear mechanism. The result indicates that drilling with the nanoparticle- enhanced lubricant was better in resisting the wear and improving the drill life to some extent

  19. Experimental test program for evaluation of solid lubricant coating as applied to compliant foil gas bearings to 315 deg C

    NASA Technical Reports Server (NTRS)

    Wagner, R. C.

    1985-01-01

    An experimental apparatus and test procedure was developed to compare the performance of two solid lubricant coatings for air lubricated compliant foil gas bearings in the temperature range of 25 to 315 C. Polyimide bonded additive (SBGC) were tested extensively for durability and frictional characteristics. A partial arc bearing constructed of Inconel X-750 was coated on the bore with one of these coatings. The foil was subjected to repeated start/stop cycles. Performance comparisons reveal that although both coatings survive thousands of start/stop cycles, only the PBGF coated bearing achieves the specified 9000 start/stops. There is enough wear on the SBGC coated bearing to warrant termination of the test prior to 9000 start/stop cycles due to coating failure. The frictional characteristics of the PBGF are better at the elevated temperatures than at lower temperatures; a marked increase in sliding friction occurs as the temperature decreases. The SBGC maintains relatively constant frictional characteristics independent of operating temperature.

  20. Polyimide bonded graphite fluoride: A new long life solid lubricant coating

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.; Sliney, H. E.

    1972-01-01

    Solid lubricant film consisting of polyimide varnish as binder and graphite fluoride as lubricant is described. Comparative wear tests with other solid lubricants were conducted and results are shown in graph form. Test equipment used in conducting wear tests is reported.

  1. A study of the formation and self-lubrication mechanisms of boric acid films on boric oxide coatings

    SciTech Connect

    Erdemir, A.; Fenske, G.R.; Erck, R.A.

    1990-01-01

    An investigation was made of the formation and self-lubrication mechanisms of boric acid films on boric oxide coatings prepared by vacuum evaporation. Measured friction coefficients of a steel ball sliding on a boric-oxide-coated-steel disk and a sapphire ball sliding on a boric-oxide-coated-alumina disk were 0.025 to 0.05 at steady state, depending on load and substrate material. This low friction was correlated with the formation of a lubricious boric acid film on boric oxide coatings exposed to open air. For the mechanism of self-lubrication, the layered-triclinic-crystal structure of boric acid was proposed. The atoms constituting each boric acid molecule are arrayed in closely packed and strongly bonded layers that are 0.318 nm apart and held together by weak forces, such as van der Waals. It is hypothesized that during sliding, these layers can align themselves parallel to the direction of relative motion, and once so aligned,, can slide over one another with relative ease to provide low friction. Structural and chemical findings were included to substantiate the proposed solid lubrication mechanism. 15 refs., 5 figs.

  2. Lubricating Properties of Ceramic-Bonded Calcium Fluoride Coatings on Nickel-Base Alloys from 75 to 1900 deg F

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1962-01-01

    The endurance life and the friction coefficient of ceramic-bonded calcium fluoride (CaF2) coatings on nickel-base alloys were determined at temperatures from 75 F to 1900 F. The specimen configuration consisted of a hemispherical rider (3/16-in. rad.) sliding against the flat surface of a rotating disk. Increasing the ambient temperature (up to 1500 F) or the sliding velocity generally reduced the friction coefficient and improved coating life. Base-metal selection was critical above 1500 F. For instance, cast Inconel sliding against coated Inconel X was lubricated effectively to 1500 F, but at 1600 F severe blistering of the coatings occurred. However, good lubrication and adherence were obtained for Rene 41 sliding against coated Rene 41 at temperatures up to 1900 F; no blisters developed, coating wear life was fairly good, and the rider wear rate was significantly lower than for the unlubricated metals. Friction coefficients were 0.12 at 1500 F, 0.15 at 1700 F, and 0.17 at 1800 F and 1900 F. Because of its ready availability, Inconel X appears to be the preferred substrate alloy for applications in which the temperature does not exceed 1500 F. Rene 41 would have to be used in applications involving higher temperatures. Improved coating life was derived by either preoxidizing the substrate metals prior to the coating application or by applying a very thin (less than 0.0002 in.) burnished and sintered overlay to the surface of the coating. Preoxidation did not affect the friction coefficient. The overlay generally resulted in a higher friction coefficient than that obtained without the overlay. The combination of both modifications resulted in longer coating life and in friction coefficients intermediate between those obtained with either modification alone.

  3. High temperature self-lubricating coatings for air lubricated foil bearings for the automotive gas turbine engine

    NASA Technical Reports Server (NTRS)

    Bhushan, B.

    1980-01-01

    coating combinations were developed for compliant surface bearings and journals to be used in an automotive gas turbine engine. The coatings were able to withstand the sliding start/stops during rotor liftoff and touchdown and occasional short time, high speed rubs under representative loading of the engine. Some dozen coating variations of CdO-graphite, Cr2O3 (by sputtering) and CaF2 (plasma sprayed) were identified. The coatings were optimized and they were examined for stoichiometry, metallurgical condition, and adhesion. Sputtered Cr2O3 was most adherent when optimum parameters were used and it was applied on an annealed (soft) substrate. Metallic binders and interlayers were used to improve the ductility and the adherence.

  4. Composition optimization of self-lubricating chromium carbide-based composite coatings for use to 760 deg C

    NASA Technical Reports Server (NTRS)

    Dellacorte, C.; Sliney, H. E.

    1986-01-01

    This paper describes new compositions of self-lubricating coatings that contain chromium carbide. A bonded chromium carbide was used as the base stock because of the known excellent wear resistance and the chemical stability of chromium carbide. Additives were silver and barium fluoride/calcium fluoride eutectic. The coating constituents were treated as a ternary system consisting of: (1) the bonded carbide base material, (2) silver, and (3) the eutectic. A study to determine the optimum amounts of each constituent was performed. The various compositions were prepared by powder blending. The blended powders were then plasma sprayed onto superalloy substrates and diamond ground to the desired coating thickness. Friction and wear studies were performed at temperatures from 25 to 760 C in helium and hydrogen. A variety of counterface materials were evaluated with the objective of discovering a satisfactory metal/coating sliding combination for potential applications such as piston ring/cylinder liner couples for Stirling engines.

  5. Composition optimization of self-lubricating chromium-carbide-based composite coatings for use to 760 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Chris; Sliney, Harold E.

    1987-01-01

    This paper describes new compositions of self-lubricating coatings that contain chromium carbide. A bonded chromium carbide was used as the base stock because of the known excellent wear resistance and the chemical stability of chromium carbide. Additives were silver and barium fluoride/calcium fluoride eutectic. The coating constituents were treated as a ternary system consisting of: (1) the bonded carbide base material, (2) silver, and (3) the eutectic. A study to determine the optimum amounts of each constituent was performed. The various compositions were prepared by powder blending. The blended powders were then plasma sprayed onto superalloy substrates and diamond ground to the desired coating thickness. Friction and wear studies were performed at temperatures from 25 to 760 C in helium and hydrogen. A variety of counterface materials were evaluated with the objective of discovering a satisfactory metal/coating sliding combination for potential applications such as piston ring/cylinder liner couples for Stirling engines.

  6. Composition optimization of self-lubricating chromium carbide-based composite coatings for use to 760/sup 0/C

    SciTech Connect

    DellaCorte, C.; Sliney, H.E.

    1986-01-01

    This paper describes new compositions of self-lubricating coatings that contain chromium carbide. A bonded chromium carbide was used as the ''base stock'' because of the known excellent wear resistance and the chemical stability of chromium carbide. ''Additives'' were silver and barium fluoride/calcium fluoride eutectic. The coating constituents were treated as a termary system consisting of: (1) the bonded carbide base material, (2) silver, and (3) the eutectic. A study to determine the optimum amounts of each constituent was performed. The various compositions were prepared by powder blending. The blended powders were then plasma sprayed onto a superalloy substrates and diamond ground to the desired coating thickness. Friction and wear studies were performed at temperatures from 25 to 760/sup 0/C in helium and hydrogen. A variety of counterface materials were evaluated with the objective of discovering a satisfactory metal/coating sliding combination for potential applications such as piston ring/cylinder liner couples for Stirling engines.

  7. Plasma-sprayed, self-lubricating coatings for use from cryogenic temperatures to 870 deg C (1600 deg F)

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1975-01-01

    A plasma-sprayed coating is described with good lubricating properties over a wide temperature range. The coating, designated NASA LUBE PS101, contains silver, nichrome, calcium fluoride, and an oxidation protective glass. Oscillating tests were conducted of self-aligning, plain cylindrical bearings, in which the bore was lined with 0.025 cm (0.010 in.) thick coatings of PS101; these were conducted at a radial load of 3.5 x 10 to the 7th power N/sq m (5000 psi) in nitrogen gas at -107 C (-160 F), in vacuum at room temperature, and in air from room temperature to 870 C (1600 F). Friction coefficients were less than 0.25 in all cases and wear rates were low. The coating is not brittle, and it has adequate oxidation resistance in air to at least 870 C.

  8. Corrosion protection of steel by thin coatings of starch-oil dry lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. Dry lubricants reduce friction between two metal surfaces. This research investigated the inhibition of corrosive behavior a dry lubricant formulation consisting of jet-cooked corn starch and soyb...

  9. Composition optimization of chromium carbide based solid lubricant coatings for foil gas bearings at temperatures to 650 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher

    1987-01-01

    A test program to determine the optimum composition of chromium carbide based solid lubricant coatings for compliant gas bearings is described. The friction and wear properties of the coatings are evaluated using a foil gas bearing test apparatus. The various coatings were prepared by powder blending, then plasma sprayed onto Inconel 718 test journals and diamond ground to the desired coating thickness and surface finish. The journals were operated against preoxidized nickel-chromium alloy foils. The test bearings were subjected to repeated start/stop cycles under a 14 kPa (2 psi) bearing unit load. The bearings were tested for 9000 start/stop cycles or until the specimen wear reached a predetermined failure level. In general, the addition of silver and eutectic to the chromium carbide base stock significantly reduced foil wear and increased journal coating wear. The optimum coating composition, PS212 (70 wt% metal bonded Cr3C2, 15 wt% Ag, 15% BaF2/CaF2 eutectic), reduced foil wear by a factor of two and displayed coating wear well within acceptable limits. The load capacity of the bearing using the plasma-sprayed coating prior to and after a run-in period was ascertained and compared to polished Inconel 718 specimens.

  10. Friction and wear of self-lubricating TiN-MoS{sub 2} coatings produced by chemical vapor deposition

    SciTech Connect

    Blau, P.J.; Yust, C.S.; Bae, Y.W.; Besmann, T.M.; Lee, W.Y.

    1994-12-31

    The purpose of the work reported here was to develop special chemical vapor deposition (CVD) methods to produce self-lubricating ceramic coatings in which the lubricating and structural phases were co-deposited on Ti-6Al-4V alloy substrates. These novel composite coatings are based on a system containing titanium nitride and molybdenum disulfide. The method for producing these coatings and their sliding behavior against silicon nitride counterfaces, in the temperature range 20--700 C in air, are described. The initial sliding friction coefficients for the composite coatings at room temperature were 0.07--0.30, but longer-term transitions to higher friction occurred, and specimen-to-specimen test variations suggested that further developments of the deposition process are required to assure repeatable friction and wear results. Friction and wear tests at 300 and 700 C produced encouraging results, but tests run at an intermediate temperate of 400 C exhibited friction coefficients of 1.0 or more. Oxidation and a change in the nature of the debris layers formed during sliding are believed to be responsible for this behavior.

  11. Bonded Lubricants

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Another spinoff to the food processing industry involves a dry lubricant developed by General Magnaplate Corp. of Linden, N.J. Used in such spacecraft as Apollo, Skylab and Viking, the lubricant is a coating bonded to metal surfaces providing permanent lubrication and corrosion resistance. The coating lengthens equipment life and permits machinery to be operated at greater speed, thus increasing productivity and reducing costs. Bonded lubricants are used in scores of commercia1 applications. They have proved particularly valuable to food processing firms because, while increasing production efficiency, they also help meet the stringent USDA sanitation codes for food-handling equipment. For example, a cookie manufacturer plagued production interruptions because sticky batter was clogging the cookie molds had the brass molds coated to solve the problem. Similarly, a pasta producer faced USDA action on a sanitation violation because dough was clinging to an automatic ravioli-forming machine; use of the anti-stick coating on the steel forming plates solved the dual problem of sanitation deficiency and production line downtime.

  12. Waterborne firm coating for temporary protection of parts, providing controlled lubrication during assembly

    SciTech Connect

    Hayner, R.E.

    1987-03-03

    This patent describes a protective, emulsified oil in water, dispersible, lubricant coating composition having a pH in the range of about 7.0 to 10, and capable of application and flow on a threaded solid substrate consisting essentially of: A. about 65 to 99% by weight of a composition comprising: (1) about 0.5 to 30 parts by weight of organic wax components having a melting point above 50/sup 0/C, the wax container ester groups; (2) about 0.5 to 6 parts of a surfactant comprising 2 to 8% of carboxylic acid and about 1 to 5% of an amine, the acid and the amine forming a salt providing at least a portion of a surfactant; (3) about 10 to 30 parts of a coupling agent comprising a C/sub 5/-C/sub 30/ liquid hydrocarbon coupling component and a C/sub 2/-C/sub 20/ alcohol in the ratio of between 1:1 and 10:1 by weight respectively, selected from the group consisting of: mineral spirits, kerosene, ethylene glycol ether, butyl cellosolve, diethylene glycol monoethyl ether, ethylene glycol monopropyl ether, propyl cellosolve, ethyl cellosolve, diethylene glycol monoethyl ether, ethylene glycol monoacetate, diethylene glycol monoproprionate, diethylene glycol monoacetate, propylene glycol monoacetate, ethanol, isopropanol and isobutanol; and (4) about 30 to 97 parts of water the sum of all parts being equal to 100; and (B) about 3.5 to 9% total pigment comprising about 0.4 to 4% by weight carbon black.

  13. The Effect of Compositional Tailoring on the Thermal Expansion and Tribological Properties of PS300: A Solid Lubricant Composite Coating

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Fellenstein, J. A.

    1996-01-01

    This paper describes a research program in which the goal is to alter the thermal expansion coefficient of a composite solid lubricant coating, PS300, by compositional tailoring. PS300 is a plasma sprayed coating consisting of chrome oxide, silver and barium fluoride/calcium fluoride eutectic in NiCr binder. By adjusting the composition, the thermal expansion coefficient can be altered, and hence chosen, to more closely match a selected substrate preventing coating spallation at extreme temperatures. Thermal expansion coefficients (CTE) for a variety of compositions were measured from 25 to 800 C using a commercial dilatometer. The CTE's ranged from 7.0 to 13 x lO(exp -6)/deg C depending on the binder content. Subsequent tribological testing of a modified composition indicated that friction and wear properties were relatively insensitive to compositional tailoring.

  14. The Evaluation of a Modified Chrome Oxide Based High Temperature Solid Lubricant Coating for Foil Gas Bearings

    NASA Technical Reports Server (NTRS)

    DellaCorte, Chris

    1998-01-01

    This paper describes the friction and wear performance of PS304, a modified chrome oxide based coating, for foil gas bearings. PS304 contains 60 wt% NiCr binder, 20 wt% Cr2O3 hardener, and 10 wt% each Ag, and BaF2/CaF2 lubricants. For evaluation, the coating is plasma spray deposited onto test journals which are slid against a superalloy partial arc foil bearing. The test load was 10 KPa (1.5 psi) and the bearings were run under start/stop cyclic conditions. The data show good wear performance of the bearing, especially at temperatures above 25 deg. C. Bearing friction was moderate (micron approx. or equal to 0.4) over the entire temperature range. Based upon the results obtained, the PS304 coating has promise for high temperature, oil-free turbomachinery applications.

  15. Engine Lubricant

    NASA Technical Reports Server (NTRS)

    1993-01-01

    PS 212, a plasma-sprayed coating developed by NASA, is used to coat valves in a new rotorcam engine. The coating eliminates the need for a liquid lubricant in the rotorcam, which has no crankshaft, flywheel, distributor or water pump. Developed by Murray United Development Corporation, it is a rotary engine only 10 inches long with four cylinders radiating outward from a central axle. Company officials say the engine will be lighter, more compact and cheaper to manufacture than current engines and will feature cleaner exhaust emissions. A licensing arrangement with a manufacturer is under negotiation. Primary applications are for automobiles, but the engine may also be used in light aircraft.

  16. Fabrication and Wear Behavior Analysis on AlCrFeNi High Entropy Alloy Coating Under Dry Sliding and Oil Lubrication Test Conditions

    NASA Astrophysics Data System (ADS)

    Tang, Yipin; Wang, Shouren; Sun, Bin; Wang, Yan; Qiao, Yang

    2016-03-01

    In this paper, AlCrFeNi high entropy alloy coating was fabricated on the surface of Q235 steel using hot pressing sintering process. The coating has the controlled thickness size and excellent mechanical properties. Scanning electron microscopy (SEM), XRD and hardness testing method were used to study the morphology, phase structure and hardness of high entropy alloys coating. The lattice distortion plays a significant role in increasing the hardness. Coating formation mechanism caused by the element diffusion under the hot pressing effect is also discussed in the paper. Simultaneously, the dry sliding and oil lubrication wear tests, wear morphology observation and wear mechanism discussion were completed. As the result shows, AlCrFeNi high entropy alloys coating exhibits superior wear resistance either at dry sliding or oil lubrication tests owing to its hard high entropy solid solution structure.

  17. Corrosion protection of steel by thin coatings of starch-oil dry lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion of materials is one of the most serious and challenging problems faced 3 worldwide by industry. This research investigated the inhibition of corrosive behavior a 4 dry lubricant formulation consisting of jet-cooked corn starch and soybean oil on SAE 5 1010 steel. Electrochemical Impedance ...

  18. The Effect of Tic Coated Balls and Stress on the Lubricant Lifetime of a Synthetic Hydrocarbon (pennzane 2001A) Using a Vacuum Spiral Orbit Tribometer

    NASA Technical Reports Server (NTRS)

    Jansen, Mark J.; Jones, William R., Jr.; Pepper, Stephen V.; Wheeler, Donald R.; Schroeer, Achim; Fluehmann, Freddy; Loewenthal, Stuart H.; Shogrin, Bradley A.

    2000-01-01

    A vacuum spiral orbit rolling contact tribometer was used to determine effect of varying mean Hertzian stress (1.0, 1.5, 2.0 GPa) and the use of 440C and TiC coated 440C balls on lubricant lifetime of a synthetic hydrocarbon (Pennzane 2001A) on 440C stainless steel. Conditions included 210 rpm, approx. 50 micrograms lubricant, an initial vacuum < 1.3xl0(exp-6) Pa, and room temperature (approx. 23 C). Increasing the mean Hertzian stress resulted in an exponential decrease in lubricant lifetime for both material combinations. Substituting a TiC coated 440C ball showed no increase in lifetime over the 440C ball. The decreasing lifetime with increasing stress level correlated well with energy dissipation calculations.

  19. Tribological Performance Optimization of Electroless Ni-B Coating under Lubricated Condition using Hybrid Grey Fuzzy Logic

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Arkadeb; Duari, Santanu; Barman, Tapan Kumar; Sahoo, Prasanta

    2015-11-01

    Deposition of nickel coating and its alloys using electroless method has received wide acceptance by researchers and even the industries because of their excellent tribological properties. The present experimental investigation deals with the behaviour of electroless Ni-B coating under lubricated condition on a pin-on-disc tribotester. An attempt is made to minimize the friction and wear characteristics simultaneously by optimizing three test parameters i.e. the applied normal load, speed and time of sliding using grey fuzzy reasoning analysis. The friction and wear tests are carried out based on Taguchi's L27 orthogonal array of experiments. 3D surface and contour plots are generated to analyze the trends in variation of friction and wear of the deposits considering the combined effect of the design variables. Analysis of variance is done to find out the contribution of each test parameter and their interactions in controlling the friction and wear behaviour of electroless Ni-B coating. Surface morphology, phase transformation and coating composition analysis are done with the help of scanning electron microscopy, X-ray diffraction analysis and energy dispersive X-ray analysis respectively.

  20. Effects of silver and group II fluoride solid lubricant additions to plasma-sprayed chromium carbide coatings for foil gas bearings to 650 C

    NASA Technical Reports Server (NTRS)

    Wagner, R. C.; Sliney, Harold E.

    1986-01-01

    A new self-lubricating coating composition of nickel aluminide-bonded chromium carbide formulated with silver and Group II fluorides was developed in a research program on high temperature solid lubricants. One of the proposed applications for this new coating composition is as a wide temperature spectrum solid lubricant for complaint foil gas bearings. Friction and wear properties were obtained using a foil gas bearing start-stop apparatus at temperatures from 25 to 650 C. The journals were Inconel 748. Some were coated with the plasma sprayed experimental coating, others with unmodified nickel aluminide/chromium carbide as a baseline for comparison. The additional components were provided to assist in achieving low friction over the temperature range of interest. Uncoated, preoxidized Inconel X-750 foil bearings were operated against these surfaces. The foils were subjected to repeated start/stop cycles under a 14-kPa (2-Psi) bearing unit loading. Sliding contact occurred during lift-off and coastdown at surface velocities less than 6 m/s (3000 rPm). Testing continued until 9000 start/stop cycles were accumulated or until a rise in starting torque indicated the journal/bearing had failed. Comparison in coating performance as well as discussions of their properties and methods of application are given.

  1. The tribology of PS212 coatings and PM212 composites for the lubrication of titanium 6Al-4V components of a Stirling engine space power system

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Lukaszewicz, Victor; Dellacorte, Christopher

    1994-01-01

    The Stirling space power machine incorporates a linear alternator to generate electrical power. The alternator is a reciprocating device that is driven by a solar or nuclear-powered Stirling engine. The power piston and cylinder are made of titanium 6Al-4V (Ti6-4) alloy, and are designed to be lubricated by a hydrodynamically-generated gas film. Rubbing occurs during starts and stops and there is the possibility of an occasional high speed rub. Since titanium is known to have a severe galling tendency in sliding contacts, a 'back-up', self-lubricating coating on the cylinder and/or the piston is needed. This report describes the results of a research program to study the lubrication of Ti6-4 with the following chromium carbide based materials: plasma-sprayed PS212 coatings and sintered PM212 counterfaces. Program objectives are to achieve adherent coatings on Ti6-4 and to measure the friction and wear characteristics of the following sliding combinations under conditions simulative of the Stirling-driven space power linear alternator: Ti6-4/Ti6-4 baseline, Ti6-4/PS212-coated Ti6-4, and PS212-coated Ti6-4/PM212.

  2. Preliminary evaluation of PS300: A new self-lubricating high temperature composite coating for use to 800{degrees}C

    SciTech Connect

    DellaCorte, C.; Edmonds, B.J.

    1996-12-31

    This paper introduces PS300, a plasma sprayed, self-lubricating composite coating for use in sliding contacts at temperatures to 800{degrees}C. PS300 is a metal bonded chrome oxide coating with silver and BaF{sub 2}/CaF{sub 2} eutectic solid lubricant additives. PS300 is similar to PS200, a chromium carbide based coating; which is currently being investigated for a variety of tribological applications. In pin-on-disk testing up to 650{degrees}C, PS300 exhibited comparable friction and wear properties to PS200. The PS300 matrix, which is predominantly chromium oxide rather than chromium carbide, does not require diamond grinding and polishes readily with silicon carbide abrasives greatly reducing manufacturing costs compared to PS200. It is anticipated that PS300 has potential for sliding bearing and seal applications in both aerospace and general industry.

  3. MS212--A Homogeneous Sputtered Solid Lubricant Coating for Use to 800 C

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Waters, William J.; Soltis, Richard

    1997-01-01

    Composite coatings containing chromium carbide, stable fluorides and silver were prepared by magnetron sputtering. The microstructure of the coatings is very homogeneous compared to that of plasma sprayed and sintered versions of the same chemical composition. Friction and wear of MS212-coated and baseline uncoated aluminum and Inconel X-750 are compared. At room temperature, the friction and wear of coated aluminum is dramatically better compared to the baseline. The acceptable load is limited by deformation of the soft aluminum substrate. In the case of the nickel alloy, lower friction is observed for the coated alloy at all temperatures up to the maximum test temperature of 800 C. Pin wear factors for sliding against the coated alloy are lower than the baseline at room temperature and 350 C, and comparable to baseline wear at higher test temperatures. Low baseline wear at high temperatures is due to the lubricious nature of the natural oxides formed on nickel-chromium alloys in a hot, oxidizing atmosphere. No load limit was found for coated Inconel X-750 at loads up to five times the load limit for coated aluminum.

  4. Friction and Wear Behavior of Plasma-Sprayed Al2O3-13 wt.%TiO2 Coatings Under the Lubrication of Liquid Paraffin

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoqin; An, Yulong; Hou, Guoliang; Zhou, Huidi; Chen, Jianmin

    2014-04-01

    Two types of ceramic composite coatings (denoted as N-AT13 coating and M-AT13 coating) were fabricated on 1Cr18Ni9Ti stainless steel substrate from ultra-fine and coarse Al2O3-13%TiO2 feedstocks by air plasma spraying. The friction and wear behavior of as-prepared coatings sliding against Al2O3 and stainless steel balls under the lubrication of liquid paraffin was evaluated with an SRV friction and wear tester (Optimol, Germany). The fractured and worn surfaces of the coatings were observed using a scanning electron microscope and a field-emission scanning electron microscope; and the wear mechanisms of the coatings were discussed based on scanning electron microscopic analysis and energy dispersive spectrometric analysis. Results show that N-AT13 coating possesses a unique microstructure and strong inter-splat bonding, thereby showing increased microhardness and bonding strength as well as much better friction-reduction and wear resistance than M-AT13 coating. Moreover, there exist differences in the wear mechanisms of N-AT13 and M-AT13 coatings which slide against ceramic and stainless steel balls under the lubrication of liquid paraffin. Namely, with the increase of normal load, the burnishing of N-AT13 coating coupled with Al2O3 ball is gradually transformed to grain-abrasion and deformation, while M-AT13 coating is dominated by grain-pullout and brittle fracture in the whole range of tested normal load.

  5. AlSiTiN and AlSiCrN multilayer coatings: Effects of structure and surface composition on tribological behavior under dry and lubricated conditions

    NASA Astrophysics Data System (ADS)

    Faga, Maria Giulia; Gautier, Giovanna; Cartasegna, Federico; Priarone, Paolo C.; Settineri, Luca

    2016-03-01

    Nanocomposite coatings have been widely studied over the last years because of their high potential in several applications. The increased interest for these coatings prompted the authors to study the tribological properties of two nanocomposites under dry and lubricated conditions (applying typical MQL media), in order to assess the influence of the surface and bulk properties on friction evolution. To this purpose, multilayer and nanocomposite AlSiTiN and AlSiCrN coatings were deposited onto tungsten carbide-cobalt (WC-Co) samples. Uncoated WC-Co materials were used as reference. Coatings were analyzed in terms of hardness and adhesion. The structure of the samples was assessed by X-ray diffraction (XRD), while the surface composition was studied by XPS analysis. Friction tests were carried out under both dry and lubricated conditions using an inox ball as counterpart. Both coatings showed high hardness and good adhesion to the substrate. As far as the friction properties are concerned, in dry conditions the surface properties affect the sliding contact at the early beginning, while bulk structure and tribolayer formation determine the main behavior. Only AlSiTiN coating shows a low and stable coefficient of friction (COF) under dry condition, while the use of MQL media results in a rapid stabilization of the COF for all the materials.

  6. Effect of microscale texture on cutting performance of WC/Co-based TiAlN coated tools under different lubrication conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Kedong; Deng, Jianxin; Xing, Youqiang; Li, Shipeng; Gao, Huanhuan

    2015-01-01

    Commonly known the severe friction between the tool and chip affects the tool life and the quality of the machined surfaces. Introducing a lubricant into the tool-chip interface can be used to alleviate the friction, the effectiveness of which may be improved by surface texturing of the tools. Thus, surface textures were fabricated using laser on the rake of the cemented carbide (WC/Co) inserts, then TiAlN films were coated on the textured tools. The effect of the textures on the cutting performance was investigated using the textured coated tools and conventional coated tools in cutting AISI 1045 hardened steel tests. Two batches of cutting tests were carried out, in regimes of full and starved lubrication. The machining performance was assessed in terms of the cutting forces, friction coefficient at the tool-chip interface, surface roughness of machined workpiece and tool wear on the rake face. Results show that the cutting performance of textured tools was enhanced, especially under the full lubrication condition.

  7. (Ag,Cu)-Ta-O ternaries as high-temperature solid-lubricant coatings.

    PubMed

    Gao, Hongyu; Otero-de-la-Roza, Alberto; Gu, Jingjing; Stone, D'Arcy; Aouadi, Samir M; Johnson, Erin R; Martini, Ashlie

    2015-07-22

    Ternary oxides have gained increasing attention due to their potential use as solid lubricants at elevated temperatures. In this work, the tribological properties of three ternary oxides-AgTaO3, CuTaO3, and CuTa2O6-were studied using a combination of density-functional theory (DFT), molecular dynamics (MD) simulations with newly developed empirical potential parameters, and experimental measurements (AgTaO3 and CuTa2O6 only). Our results show that the MD-predicted friction force follows the trend AgTaO3 < CuTaO3 < CuTa2O6, which is consistent with the experimentally measured coefficients of friction. The wear performance from both MD and experiment exhibits the opposite trend, with CuTa2O6 providing the best resistance to wear. The sliding mechanisms are investigated using experimental characterization of the film composition after sliding, quantification of Ag or Cu cluster formation at the interface during the evolution of the film in MD, and DFT energy barriers for atom migration on the material surface. All our observations are consistent with the hypothesis that the formation of metal (or metal oxide) clusters on the surface are responsible for the friction and wear behavior of these materials. PMID:26106877

  8. Molecular dynamics simulations of the tribological behaviour of a water-lubricated amorphous carbon-fluorine PECVD coating

    NASA Astrophysics Data System (ADS)

    Rullich, Markus; Weiss, Volker C.; Frauenheim, Thomas

    2013-07-01

    Hybrid bearings comprising ceramic balls and steel rings exhibit increased wear-resistance and a reduced coefficient of friction (COF) compared with standard steel bearings. Using plasma-enhanced chemical vapour deposition (PECVD) coatings to modify the surface properties, the performance of these bearings can be further improved. Fluorine-containing amorphous hydrogenated carbon (a-C : F : H) films are well suited to this purpose. To study the influence of such coatings on the friction characteristics of key parts of hybrid bearings, a model of an a-C : F : H film was constructed and employed in molecular dynamics simulations of two slabs sliding past each other, lubricated by water. With one slab being pulled by a virtual spring, the perpendicular force (load) was kept constant using a barostat. For comparison, a system of two silicon dioxide (cristobalite) slabs and a mixed system consisting of a cristobalite slab and an a-C : F : H slab were investigated. Our results indicate a linear dependence of the friction force on the perpendicular force. With an increasing amount of water between the slabs, the COFs decrease. A decrease in temperature leads to an increased COF, while a decrease in the relative velocity of the slabs does not influence the COF between two a-C : F : H slabs, but reduces the COF for the other two systems. Our results for the COF and its dependence on temperature and relative sliding velocity generally agree well both with experiments and with simulations for similar systems reported in the literature.

  9. Solid lubricant materials for high temperatures: A review

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1985-01-01

    Solid lubricants that can be used above 300 C in air are discussed, including coatings and self-lubricating composite bearing materials. The lubricants considered are representative dichalcogenides, graphite, graphite fluoride, polyimides, soft oxides, oxidatively stable fluorides, and hard coating materials. A few general design considerations revelant to solid lubrication are interspersed.

  10. CVD Diamond, DLC, and c-BN Coatings for Solid Film Lubrication

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa; Murakawa, Masao; Watanabe, Shuichi; Takeuchi, Sadao; Miyake, Shojiro; Wu, Richard L. C.

    1998-01-01

    The main criteria for judging coating performance were coefficient of friction and wear rate, which had to be less than 0.1 and 10(exp -6) cubic MM /(N*m), respectively. Carbon- and nitrogen-ion-implanted, fine-grain, chemical-vapor-deposited (CVD) diamond and diamondlike carbon (DLC) ion beam deposited on fine-grain CVD diamond met the criteria regardless of environment (vacuum, nitrogen, and air).

  11. CVD Diamond, DLC, and c-BN Coatings for Solid Film Lubrication

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1998-01-01

    When the main criteria for judging coating performance were coefficient of friction and wear rate, which had to be less than 0.1 and 10(exp -6) mm(exp 3)/N-m, respectively, carbon- and nitrogen-ion-implanted, fine-grain CVD diamond and DLC ion beam deposited on fine-grain CVD diamond met the requirements regardless of environment (vacuum, nitrogen, and air).

  12. The Effect of Stress and TiC Coated Balls on Lubricant Lifetimes Using a Vacuum Ball-on-Plate Rolling Contact Tribometer

    NASA Technical Reports Server (NTRS)

    Jones, William R., Jr.; Jansen, Mark J.; Helmick, Larry H.; Nguyen, QuynhGiao; Wheeler, Donald R.; Boving, Hans J.

    1999-01-01

    A vacuum ball-on-plate rolling contact tribometer was used to determine the relative lifetimes of a perfluoropolyether (Krytox 143 AC) on 440C stainless steel. The effect of mean Hertzian stresses (0.75, 1.0, 1.5, and 2.0 GPa) and the use of TiC-coated balls on lubricant lifetime was studied. Other conditions included: 100 rpm, 50 micro-g of lubricant, an initial vacuum level of less than 1.0 x 10(exp -8) Torr, and room temperature (23 C). Increasing the mean Hertzian stress from 0.75 to 2.0 GPa results in an exponential decrease in lubricant lifetime for both material combinations. However, substituting a TiC ball for the 440C ball quadrupled lifetime at low stress levels (0.75 and 1.0 GPa) and doubled life at higher stresses (1.5 and 2.0 GPa). The reduced reactivity of the TiC surface with the PFPE lubricant is considered to be the reason for this enhancement. Decreasing lifetime with increasing stress levels correlated well with energy dissipation calculations.

  13. The Effect of Stress and TiC Coated Balls on Lubricant Lifetimes Using a Vacuum Ball-on-Plate Rolling Contact Tribometer

    NASA Technical Reports Server (NTRS)

    Jones, William R., Jr.; Jansen, Mark J.; Helmick, Larry H.; Nguyen, QuynhGiao; Wheeler, Donald R.; Voving, Hans J.

    1999-01-01

    A vacuum ball-on-plate rolling contact tribometer was used to determine the relative lifetimes of a perfluoropolyether (Krytox 143 AC) on 440C stainless steel. The effect of mean Hertzian stresses (0.75, 1.0, 1.5 and 2.0 GPa) and the use of TiC coated balls on lubricant lifetime was studied. Other conditions included: approximately 100 rpm, approximately 50 micrograms of lubricant, an initial vacuum level of less than 1.0 x 1O(exp -8) Torr, and room temperature (approximately 23 C). increasing the mean Hertzian stress from 0.75 to 2.0 GPa results in an exponential decrease in lubricant lifetime for both material combinations. However. substituting a TiC ball for the 440C ball quadrupled lifetime at low stress levels (0.75 and 1.0 GPa) and doubled life at higher stresses (1.5 and 2.0 GPa). The reduced reactivity of the TiC surface with the PFPE lubricant is considered to be the reason for this enhancement. Decreasing lifetime with increasing stress levels correlated well with energy dissipation calculations.

  14. Impact of Nanometer Graphite Addition on the Anti-deliquescence and Tribological Properties of Ni/MoS2 Lubricating Coating

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Li, G. L.; Wang, H. D.; Xu, B. S.; Ma, G. Z.

    In order to improve the long-standing problem of MoS2 coating that lubrication performance drop dramatic after storage in humid air, using nano-composite electro brush plating technology and Ni/MoS2-C combination coating with thinness of 100 μm was succeed deposited on GCr15 substrate. Microstructure, surface morphology and elements of this composite coating were analyzed using SEM, XPS and TEM while phase structure was tested by XRD. The tribological properties of this composite coating were tested by MSTS-1; Test the preceding tribological properties of Ni/MoS2-C composite coatings to the pure Ni/MoS2 after different period storage at room temperature and 100% relative humidity atmosphere of 12 h, 24 h, and 48 h as well as the element of the chemical changes. Research shows that there is a small amount of MoS2 in pure MoS2 coatings behind a 12 hours storage in humid air became MoO3 and the tribological performance decreased significantly followed, in the same conditions composite coating with nanometer graphite addition get a preferably tribological properties while the hardness of this coating was improved by the nanometer graphite addition and combination plating showed a well duration tribological properties as a result.

  15. The Effects of Substrate Material and Thermal Processing Atmosphere on the Strength of PS304: A High Temperature Solid Lubricant Coating

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2002-01-01

    PS304, a plasma spray deposited solid lubricant coating developed for high temperature sliding contacts was deposited on nine different substrate metals, heat treated at 650C in either air or argon and subsequently tested for strength using a commercially available pull-off adhesion test. Some samples were examined metallographically to help elucidate and explain the results. As deposited coatings exhibit pull-off strengths typically between 16 and 20 MPa with failure occuring (cohesively) within the coating. Heat treatment in argon at 650 C results in a slight increase in coating (cohesive) strength of about 30 percent to 21 to 27 MPa. Heat treatment in air at 650 C results in a dramatic increase in strength to over 30 MPa, exceeding the strength of the epoxy used in the pull test. Cross section metallographic analyses show that no microstructural coating changes occur following the argon heat treatments, however, exposure to air at 650C gives rise to the formation of a second chromium-rich phase precipitate within the PS304 NiCr constituent which provides a strengthening effect and a slight (approximately 5 percent) coating thickness increase. Subsequent heat treatments do not result in any further coating changes. Based upon these studies, PS304 is a suitable coating for use on a wide variety of high temperature substrates and must be heat treated following deposition to enhance strength and ensure dimensional stability.

  16. Simulation of automotive wrist pin joint and tribological studies of tin coated Al-Si alloy, metal matrix composites and nitrogen ceramics under mixed lubrication

    NASA Astrophysics Data System (ADS)

    Wang, Qian

    Development of automotive engines with high power output demands the application of high strength materials with good tribological properties. Metal matrix composites (MMC's) and some nitrogen ceramics are of interest to replace some conventional materials in the piston/pin/connecting rod design. A simulation study has been developed to explore the possibility to employ MMC's as bearing materials and ceramics as journal materials, and to investigate the related wear mechanisms and the possible journal bearing failure mechanisms. Conventional tin coated Al-Si alloy (Al-Si/Sn) have been studied for the base line information. A mixed lubrication model for journal bearing with a soft coating has been developed and applied to the contact and temperature analysis of the Al-Si/Sn bearing. Experimental studies were performed to reveal the bearing friction and wear behavior. Tin coating exhibited great a advantage in friction reduction, however, it suffered significant wear through pitting and debonding. When the tin wore out, the Al-Si/steel contact experienced higher friction. A cast and P/M MMC's in the lubricated contact with case hardened steel and ceramic journals were studied experimentally. Without sufficient material removal in the conformal contact situation, MMC bearings in the MMC/steel pairs gained weight due to iron transfer and surface tribochemical reactions with the lubricant additives and contact failure occurred. However, the MMC/ceramic contacts demonstrated promising tribological behavior with low friction and high wear resistance, and should be considered for new journal bearing design. Ceramics are wear resistant. Ceramic surface roughness is very crucial when the journals are in contact with the tin coated bearings. In contact with MMC bearings, ceramic surface quality and fracture toughness seem to play some important roles in affecting the friction coefficient. The wear of silicon nitride and beta sialon (A) journals is pitting due to grain

  17. Sliding friction and wear behaviors of surface-coated natural serpentine mineral powders as lubricant additive

    NASA Astrophysics Data System (ADS)

    Zhang, Baosen; Xu, Yi; Gao, Fei; Shi, Peijing; Xu, Binshi; Wu, Yixiong

    2011-01-01

    This work aims to investigate the friction and wear properties of surface-coated natural serpentine powders (SP) suspended in diesel engine oil using an Optimal SRV oscillating friction and wear tester. The worn surface was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). Results indicated that the additives can improve the wear resistance and decrease friction coefficient of carbon steel friction couples. The 0.5 wt% content of serpentine powders is found most efficient in reducing friction and wear at the load of 50 N. The SEM and XPS analysis results demonstrate that a tribofilm forms on the worn surface, which is responsible for the decrease in friction and wear, mainly with iron oxides, silicon oxides, graphite and organic compounds.

  18. Friction and Wear Characteristics of Plasma-Sprayed Self-Lubrication Coating with Clad Powder at Elevated Temperatures up to 800 °C

    NASA Astrophysics Data System (ADS)

    Huang, Chuanbing; Du, Lingzhong; Zhang, Weigang

    2014-02-01

    NiCr/(Cr3C2-BaF2·CaF2) coating was fabricated by atmospheric plasma spray technology using clad powder. The coating shows low porosity, high microhardness and bonding strength, and it also exhibits good friction reduction and wear resistance at elevated temperatures up to 800 °C which is due to the formation of a kind of continuous BaF2·CaF2 eutectic lubricating film. The excellent mechanical and tribological properties of the coating are partially attributed to the protection of NiCr layer of the composite powders which can decrease oxidation, decarburization of Cr3C2, and ablation of BaF2·CaF2 eutectic during spray and deposition process.

  19. Origins of hydration lubrication.

    PubMed

    Ma, Liran; Gaisinskaya-Kipnis, Anastasia; Kampf, Nir; Klein, Jacob

    2015-01-14

    Why is friction in healthy hips and knees so low? Hydration lubrication, according to which hydration shells surrounding charges act as lubricating elements in boundary layers (including those coating cartilage in joints), has been invoked to account for the extremely low sliding friction between surfaces in aqueous media, but not well understood. Here we report the direct determination of energy dissipation within such sheared hydration shells. By trapping hydrated ions in a 0.4-1 nm gap between atomically smooth charged surfaces as they slide past each other, we are able to separate the dissipation modes of the friction and, in particular, identify the viscous losses in the subnanometre hydration shells. Our results shed light on the origins of hydration lubrication, with potential implications both for aqueous boundary lubricants and for biolubrication.

  20. Industrial Lubricants

    NASA Astrophysics Data System (ADS)

    Kajdas, C.; Karpińska, A.; Kulczycki, A.

    'Industrial lubricant' gaseous, liquid and solid products cover many applications. A new systems analysis approach is used combining heterogeneous catalysis and tribochemistry. Bearing lubricant applications are discussed in terms of the bearing film thickness and tribological regimes, for liquid and solid lubricants. Compressor and vacuum pump lubricant applications are described. The various classes of hydraulic fluids for industrial applications are explained. The properties, applications and selection of various industrial lubricants for different gears are described. Steam and industrial gas turbine lubricant formulations are discussed and the effects of their degradation products, particularly for valves and filters, are presented. Metalworking lubricant applications are divided into cutting and forming operations and their actions are described. Speciality applications such as process, textile, food-grade, slideway, cylinder and wire rope lubricants are explained.

  1. Durability studies of micro/nanoelectromechanical systems materials, coatings and lubricants at high sliding velocities (up to 10 mm/s) using a modified atomic force microscope

    NASA Astrophysics Data System (ADS)

    Tambe, Nikhil S.; Bhushan, Bharat

    2005-07-01

    Most micro/nanoelectromechanical (MEMS/NEMS) devices and components operate at very high sliding velocities (of the order of tens of mm/s to few m/s). Micro/nanoscale tribology and mechanics of these devices is crucial for evaluating reliability and failure issues. Atomic force microscopy (AFM) studies to investigate potential materials/coatings for these devices have been rendered inadequate due to inherent limitations on the highest sliding velocities achievable with commercial AFMs. We have developed a technique to study nanotribological properties at high sliding velocities (up to 10 mm/s) by modifying the commercial AFM setup with a customized closed loop piezo stage for mounting samples. Durability of materials, silicon, poly(methylmethacrylate) (PMMA) and poly(dimethlysiloxane) (PDMS), diamond-like carbon (DLC) coating and lubricants such as self-assembled monolayer of hexadecanethiol (HDT) and perfluropolyethers Z-15 and Z-DOL used in MEMS/NEMS applications, is studied at various normal loads and sliding velocities. Wear mechanisms involved at high sliding velocities are discussed. The primary wear mechanisms are deformation of the contacting asperities due to impacts in the case of silicon; phase transformation from amorphous to low shear strength graphite for DLC; localized melting due to high frictional energy dissipation for PMMA and PDMS; and displacement or removal of lubricant molecules for HDT, Z-15, and Z-DOL.

  2. Solid Lubrication Fundamentals and Applications

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2001-01-01

    Solid Lubrication Fundamentals and Applications description of the adhesion, friction, abrasion, and wear behavior of solid film lubricants and related tribological materials, including diamond and diamond-like solid films. The book details the properties of solid surfaces, clean surfaces, and contaminated surfaces as well as discussing the structures and mechanical properties of natural and synthetic diamonds; chemical-vapor-deposited diamond film; surface design and engineering toward wear-resistant, self-lubricating diamond films and coatings. The author provides selection and design criteria as well as applications for synthetic and natural coatings in the commercial, industrial and aerospace industries..

  3. Effects of heat treatment on microstructure and mechanical properties of Ni60/h-BN self-lubricating anti-wear composite coatings on 304 stainless steel by laser cladding

    NASA Astrophysics Data System (ADS)

    Lu, Xiao-Long; Liu, Xiu-Bo; Yu, Peng-Cheng; Zhai, Yong-Jie; Qiao, Shi-Jie; Wang, Ming-Di; Wang, Yong-Guang; Chen, Yao

    2015-11-01

    Laser clad Ni60/h-BN self-lubricating anti-wear composite coating on 304 stainless steel were heat treated at 600 °C (stress relief annealing) for 1 h and 2 h, respectively. Effects of the phase compositions, microstructure, microhardness, nano-indentation and tribological properties of the composite coatings with and without heat treatment had been investigated systemically. Results indicated that three coatings mainly consist of the matrix γ-(Ni, Fe) solid solution, the CrB ceramic phases and the h-BN lubricating phases. The maximum microhardness of the coatings was first increased from 667.7 HV0.5 to 765.0 HV0.5 after heat treatment for 1 h, and then decreased to 698.3 HV0.5 after heat treatment for 2 h. The hardness of γ-(Ni, Fe) solid solution without heat treatment and after heat treatment 1 h and 2 h were 5.09 GPa, 7.20 GPa and 3.77 GPa, respectively. Compared with the coating without heat treatment, the friction coefficients of the coating after heat treatment were decreased obviously. Effects of the heat treatment time on friction coefficient were negligible, but were significant on wear volume loss. Comparatively speaking, the laser clad self-lubricating anti-wear composite coating after heat treatment for 1 h presented the best anti-wear and friction reduction properties.

  4. Characterization of the surface properties of a model pharmaceutical fine powder modified with a pharmaceutical lubricant to improve flow via a mechanical dry coating approach.

    PubMed

    Zhou, Qi Tony; Denman, John A; Gengenbach, Thomas; Das, Shyamal; Qu, Li; Zhang, Hailong; Larson, Ian; Stewart, Peter J; Morton, David A V

    2011-08-01

    The aim of this study is to investigate the changes in physical and chemical surface properties of a fine lactose powder, which has been processed by a mechanical dry coating approach. A commercially available milled lactose monohydrate powder (median diameter around 20 μm) was dry coated with a pharmaceutical lubricant, magnesium stearate (MgSt). Substantial changes in bulk behavior have been shown previously and the purpose of the current work was to understand the relationship between these bulk changes and physico-chemical changes in the surface. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry results demonstrated both qualitatively and quantitatively how the chemical properties of the lactose particle surfaces had been altered. The characterization results indicated that a high-level coverage of a thin coating layer of MgSt has been created through the coating. Inverse gas chromatography was used to probe the surface energetic changes, and at conditions of finite dilution, provided a new insight into surface energy changes. This work demonstrated that the modifications of the surface physical and chemical properties correlated with the reduction in powder cohesion and improvement in powder flow.

  5. Boundary lubrication in vivo.

    PubMed

    Hills, B A

    2000-01-01

    Evidence is reviewed for the concept that the body employs essentially the same lubrication system in many sites in the body where tissues slide over each other with such ease. This system consists of fluid adjacent to surfaces coated with an oligolamellar lining of surface-active phospholipid (SAPL) acting as a back-up boundary lubricant wherever the fluid film fails to support the load--a likely event at physiological velocities. Particular attention is paid to the load-bearing joints, where the issue of identifying the vital active ingredient in synovial fluid is reviewed, coming down--perhaps predictably--in favour of SAPL. It is also explained how Lubricin and hyaluronic acid (HA) could have 'carrier' functions for the highly insoluble SAPL, while HA has good wetting properties needed to promote hydrodynamic lubrication of a very hydrophobic articular surface by an aqueous fluid wherever the load permits. In addition to friction and wear, release is included as another major role of boundary lubricants, especially relevant in environments where proteins are found, many having adhesive properties. The discussion is extended to a mention of the lubrication of prosthetic implants and to disease states where a deficiency of boundary lubricant is implicated, particular attention being paid to osteoarthritis.

  6. Solid Lubricants for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2005-01-01

    Recent breakthroughs in gas foil bearing solid lubricants and computer based modeling has enabled the development of revolulionary Oil-Free turbomachinery systems. These innovative new and solid lubricants at low speeds (start-up and shut down). Foil bearings are hydrodynamic, self acting fluid film bearings made from thin, flexible sheet metal foils. These thin foils trap a hydrodynamic lubricating air film between their surfaces and moving shaft surface. For low temperature applications, like ainrafl air cycle machines (ACM's), polymer coatings provide important solid lubrication during start-up and shut down prior to the development of the lubricating fluid film. The successful development of Oil-Free gas turbine engines requires bearings which can operate at much higher temperatures (greater than 300 C). To address this extreme solid lubrication need, NASA has invented a new family of compostie solid lubricant coatings, NASA PS300.

  7. Plasma-sprayed metal-glass and metal-glass fluoride coatings for lubrication to 900 C

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1973-01-01

    Plasma-sprayed composites, which have good oxidation-resistance and self-lubricating characteritics to 900 C, were developed. The composites are a nichrome matrix containing dispersed glass for oxidation protection and calcium fluoride for lubrication; they are applied to bearing surfaces by plasma spraying layers about 0.050 centimeters thick which are then machined to 0.025 centimeters. Oscillating bearing tests were performed in air to 900 C at unit radial loads up to 3.5 x 10 to the 7th power N/sq M (5000 psi) and a thrust load of 1960N (440 lbs). Bearings with a composite liner in the bore were in good condition after over 50,000 oscillating cycles accumulated during repeated, bearing temperatures cycles between 25 and 900 C.

  8. Plasma-sprayed metal-glass and metal-glass fluoride coatings for lubrication to 900 C

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1974-01-01

    Plasma-sprayed composites, which have good oxidation resistance and self-lubricating characteristics to 900 C, were developed. The composites are a nichrome matrix containing dispersed glass for oxidation protection and calcium fluoride for lubrication; they are applied to bearing surfaces by plasma spraying layers about 0.050 cm thick which are then machined to 0.025 cm. Oscillating bearing tests were performed in air to 900 C at unit radial loads up to 5000 psi and a thrust load of 440 lb. Bearings with a composite liner in the bore were in good condition after over 50,000 oscillating cycles accumulated during repeated bearing temperature cycles between 25 and 900 C.

  9. Solid lubricants

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1991-01-01

    The state of knowledge of solid lubricants is reviewed. The results of research on solid lubricants from the 1940's to the present are presented from a historical perspective. Emphasis is placed largely, but not exclusively, on work performed at NASA Lewis Research Center with a natural focus on aerospace applications. However, because of the generic nature of the research, the information presented in this review is applicable to most areas where solid lubricant technology is useful.

  10. Tribological evaluation of PS300: A new chrome oxide based solid lubricant coating sliding against Al2O3 From 25 to 650 C

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Laskowski, J. A.

    1996-01-01

    This paper presents the tribological characteristics of Al203 sliding against PS300; a chrome oxide based self lubricating coating. Al203 pins were slid against PS300 coated superalloy disks in air, under a 4.9 N load at velocities of 1 to 8 m/s. At a sliding velocity of 1 m/s, friction ranged from 0.6 at 25 C to 0.2 at 650 C. Wear factors for the Al203 pins were in the 10(exp -7) mm(exp 3)/N-m range and for the PS300 coating was in the 10(exp -5) mm(exp 3)/N-m range. The test results suggest that increased surface temperature resulting from either frictional heating, generated by increased sliding velocity, or ambient heating caused a reduction in friction and wear of the sliding couple. Based upon these results, the tested material combination is a promising candidate for high temperature wear applications.

  11. Thin Film Solid Lubricant Development

    NASA Technical Reports Server (NTRS)

    Benoy, Patricia A.

    1997-01-01

    Tribological coatings for high temperature sliding applications are addressed. A sputter-deposited bilayer coating of gold and chromium is investigated as a potential solid lubricant for protection of alumina substrates during sliding at high temperature. Evaluation of the tribological properties of alumina pins sliding against thin sputtered gold films on alumina substrates is presented.

  12. The tribology of PS212 coatings and PM212 composites for the lubrication of titanium 6A1-4V components of a Stirling engine space power system

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Dellacorte, Christopher; Lukaszewicz, Victor

    1995-01-01

    The Stirling space power machine incorporates a linear alternator to generate electrical power. The alternator is a reciprocating device that is driven by a solar or nuclear-powered Stirling engine. The power piston and cylinder are made of titanium 6A1-4V (Ti6-4) alloy, and are designed to be lubricated by a hydrodynamically-generated gas film. Rubbing occurs during starts and stops and there is a possibility of an occasional high speed rub. Since titanium is known to have a severe galling tendency in sliding contacts, a 'backup,' self-lubricating coating on the cylinder and/or the piston is needed. This report describes the results of a research program to study the lubrication of Ti6-4 with the following chromium carbide based materials: plasma-sprayed PS212 coatings and sintered PM212 counterfaces. Program objectives are to achieve adherent coatings on Ti6-4 and to measure the friction and wear characteristics of the following sliding combinations under conditions simulative of the Stirling-driven space power linear alternator: Ti6-4/Ti6-4 baseline, Ti6-4/PS212 coated Ti6-4, and Ps212 coated Ti6-4/PM212

  13. Evaluation of Thermal Barrier and PS-200 Self-Lubricating Coatings in an Air-Cooled Rotary Engine

    NASA Technical Reports Server (NTRS)

    Moller, Paul S.

    1995-01-01

    This project provides an evaluation of the feasibility and desirability of applying a thermal barrier coating overlaid with a wear coating on the internal surfaces of the combustion area of rotary engines. Many experiments were conducted with different combinations of coatings applied to engine components of aluminum, iron and titanium, and the engines were run on a well-instrumented test stand. Significant improvements in specific fuel consumption were achieved and the wear coating, PS-200, which was invented at NASA's Lewis Research Center, held up well under severe test conditions.

  14. Lubrication background

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1981-01-01

    Surface topography, including the various physical methods of measuring surfaces, and the various lubrication regimes (hydrodynamic, elastohydrodynamic, boundary, and mixed) are discussed. The historical development of elastohydrodynamic lubrication is outlined. The major accomplishments in four periods, the pre-1950's, the 1950's, the 1960's, and the 1970's are presented.

  15. Influence of trimethylsilane flow on the microstructure, mechanical and tribological properties of CrSiCN coatings in water lubrication

    NASA Astrophysics Data System (ADS)

    Wu, Zhiwei; Zhou, Fei; Wang, Qianzhi; Zhou, Zhifeng; Yan, Jiwang; Li, Lawrence Kwok-Yan

    2015-11-01

    CrSiCN coatings with different silicon and carbon contents were deposited on silicon wafers and 316L stainless steels using unbalanced magnetron sputtering via adjusting trimethylsilane (TMS) flow, and their microstructure and mechanical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy(SEM), X-ray photoelectrons spectroscopy(XPS) and nano-indenter, respectively. The tribological properties of CrSiCN coatings sliding against SiC balls in water were investigated using ball-on-disk tribometer. The results showed that the CrSiCN coatings had fine composite microstructure consisting of nanocrystallites of Cr(C, N) crystal and amorphous phases such as a-Si3N4 and a-C(a-CNx). The typical columnar structures changed from fine cluster to coarse ones when the Si content was beyond 3.4 at.%. With an increase in the TMS flow, the hardness and Young's modulus of Corsican coatings all first increased, and then rapidly decreased, but the compressive stress in the coatings varied in the range of 2.8-4.8 GPa. When the TMS flow was 10 sccm, the CrSiCN coatings exhibited the highest hardness of 21.3 GPa and the lowest friction coefficient (0.11) and wear rate (8.4 × 10-8 mm3/N m). But when the TMS flow was beyond 15 sccm, the tribological properties of CrSiCN coatings in water became poor.

  16. Marine Lubricants

    NASA Astrophysics Data System (ADS)

    Carter, B. H.; Green, D.

    Marine diesel engines are classified by speed, either large (medium speed) or very large (slow speed) with high efficiencies and burning low-quality fuel. Slow-speed engines, up to 200 rpm, are two-stroke with separate combustion chamber and sump connected by a crosshead, with trunk and system oil lubricants for each. Medium-speed diesels, 300-1500 rpm, are of conventional automotive design with one lubricant. Slow-speed engines use heavy fuel oil of much lower quality than conventional diesel with problems of deposit cleanliness, acidity production and oxidation. Lubricants are mainly SAE 30/40/50 monogrades using paraffinic basestocks. The main types of additives are detergents/dispersants, antioxidants, corrosion inhibitors, anti-wear/load-carrying/ep, pour-point depressants and anti-foam compounds. There are no simple systems for classifying marine lubricants, as for automotive, because of the wide range of engine design, ratings and service applications they serve. There are no standard tests; lubricant suppliers use their own tests or the Bolnes 3DNL, with final proof from field tests. Frequent lubricant analyses safeguard engines and require standard sampling procedures before determination of density, viscosity, flash point, insolubles, base number, water and wear metal content.

  17. Preparation and friction characteristics of self-lubricating TiN- MoS{sub 2} composite coatings

    SciTech Connect

    Bae, Y.W.; Lee, W.Y.; Besmann, T.M.; Yust, C.S.; Blau, P.J.

    1995-12-31

    Composite coatings consisting of distinctly discrete phases of TiN and MoS{sub 2} were codeposited on graphite and Ti-6Al-4V substrates from Ti((CH3)2N)4/NH3/MoF6/H2S gas mixtures. Chemical composition and microstructure of the coatings were studied by Auger electron spectroscopy, XRD, and TEM. Friction coefficients at room temperature in air were typically in the range of 0.07 to 0.3; they remained comparable at 573 K, but increased to 0.7 to 1.0 at 673 K. A friction coefficient of {similar_to}0.3 was, however, obtained from a composite coating tested at 973 K.

  18. Influence of boron content on the microstructure and tribological properties of Cr-B-N coatings in water lubrication

    NASA Astrophysics Data System (ADS)

    Ma, Qiang; Zhou, Fei; Gao, Song; Wu, Zhiwei; Wang, Qianzhi; Chen, Kangmin; Zhou, Zhifeng; Li, Lawrence Kwok-Yan

    2016-07-01

    Cr-B-N coatings with different boron contents were deposited on Si(1 0 0) wafers and 316 L stainless steels using unbalanced magnetron sputtering system by way of adjusting the CrB2 target currents. The microstructure and mechanical properties of Cr-B-N coatings were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), white light interferometric three dimensional profilometer and nano-indentation tester, respectively. The tribological properties of Cr-B-N/SiC tribopairs in water were studied using ball-on-disk tribometer. The results showed that the Cr-B-N coatings showed a fine nanocomposite structure consisted of CrN nanograins and amorphous BN phase regardless of boron contents, and the typical columnar structure became featureless with increasing the CrB2 target current. The hardness and reduced elastic modulus first increased to 28.9 GPa and 330 GPa at the CrB2 target current of 2 A, and then decreased gradually with further increasing the CrB2 target current to 4 A. As compared with the CrN/SiC tribopairs, the lowest friction coefficient of Cr-B-N/SiC ball tribopairs in water was 0.15, and the wear resistance of Cr-B-N coatings was effectively enhanced.

  19. Cost-Cutting Powdered Lubricant

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Scientists at NASA's Glenn Research Center developed a high-temperature, solid lubricant coating material that is saving the manufacturing industry millions of dollars. The material came out of 3 decades of tribological research, work studying high-temperature friction, lubrication, and the wearing of interacting surfaces that are in relative motion. It was developed as a shaft coating deposited by thermal spraying to protect foil air bearings used in oil-free turbomachinery, like gas turbines, and is meant to be part of a larger project: an oil-free aircraft engine capable of operating at high temperatures with increased reliability, lowered weight, reduced maintenance requirements, and increased power. This advanced coating, PS300, is a self-lubricating bearing material containing chromium oxide, with additions of a low-temperature start up lubricant (silver) and a high-temperature lubricant, making it remarkably stable at high temperatures, and better suited than previously available materials for high-stress conditions. It improves efficiency, lowers friction, reduces emissions, and has been used by NASA in advanced aeropropulsion engines, refrigeration compressors, turbochargers, and hybrid electrical turbogenerators. PS300 is ideal in any application where lowered weight and reduced maintenance are desired, and high-temperature uses and heavy operating speeds are expected. It has notable uses for the Space Agency, but it has even further-reaching potential for the industrial realm.

  20. Solid Lubrication Fundamentals and Applications. Chapter 2

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1998-01-01

    This chapter describes powerful analytical techniques capable of sampling tribological surfaces and solid-film lubricants. Some of these techniques may also be used to determine the locus of failure in a bonded structure or coated substrate; such information is important when seeking improved adhesion between a solid-film lubricant and a substrate and when seeking improved performance and long life expectancy of solid lubricants. Many examples are given here and through-out the book on the nature and character of solid surfaces and their significance in lubrication, friction, and wear. The analytical techniques used include the late spectroscopic methods.

  1. High temperature solid lubricants: When and where to use them

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1973-01-01

    The state of the art of solid lubrication for moderate to extremely high temperature lubrication (to 1600 F) is reviewed. Lubricating characteristics, stability in various environments, and relevant machine design considerations are discussed. Lubricating materials discussed include the layer lattice compounds: MoS2, WS2, graphite and graphite fluoride, the high temperature polyimide polymer, and calcium fluoride based coating and composites. The scope of the information includes results from wear testers, ball bearing, and journal bearings.

  2. High temperature solid lubricants - When and where to use them.

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1973-01-01

    This paper reviews the state of the art of solid lubrication for moderate to extremely high temperature lubrication (to 1600 F). Lubricating characteristics, stability in various environments, and relevant machine design considerations are discussed. Lubricating materials discussed include MoS2, WS2, graphite, graphite fluoride, the high temperature polymide polymer, and calcium fluoride based coatings and composites. The scope of the information includes results from wear testers, ball bearings, and journal bearings.

  3. Tethered Lubricants for Small Systems

    SciTech Connect

    Lynden A. Archer

    2006-01-09

    The objective of this research project is two-fold. First, to fundamentally understand friction and relaxation dynamics of polymer chains near surfaces; and second, to develop novel self-lubricated substrates suitable for MEMS devices. During the three-year performance period of this study the PI and his students have shown using theory and experiments that systematic introduction of disorder into tethered lubricant coatings (e.g. by using self-assembled monolayer (SAM) mixtures or SAMs with nonlinear, branched architectures) can be used to significantly reduce the friction coefficient of a surface. They have also developed a simple procedure based on dielectric spectroscopy for quantifying the effect of surface disorder on molecular relaxation in lubricant coatings. Details of research accomplishments in each area of the project are described in the body of the report.

  4. Solid lubrication design methodology, phase 2

    NASA Technical Reports Server (NTRS)

    Pallini, R. A.; Wedeven, L. D.; Ragen, M. A.; Aggarwal, B. B.

    1986-01-01

    The high temperature performance of solid lubricated rolling elements was conducted with a specially designed traction (friction) test apparatus. Graphite lubricants containing three additives (silver, phosphate glass, and zinc orthophosphate) were evaluated from room temperature to 540 C. Two hard coats were also evaluated. The evaluation of these lubricants, using a burnishing method of application, shows a reasonable transfer of lubricant and wear protection for short duration testing except in the 200 C temperature range. The graphite lubricants containing silver and zinc orthophosphate additives were more effective than the phosphate glass material over the test conditions examined. Traction coefficients ranged from a low of 0.07 to a high of 0.6. By curve fitting the traction data, empirical equations for slope and maximum traction coefficient as a function of contact pressure (P), rolling speed (U), and temperature (T) can be developed for each lubricant. A solid lubricant traction model was incorporated into an advanced bearing analysis code (SHABERTH). For comparison purposes, preliminary heat generation calculations were made for both oil and solid lubricated bearing operation. A preliminary analysis indicated a significantly higher heat generation for a solid lubricated ball bearing in a deep groove configuration. An analysis of a cylindrical roller bearing configuration showed a potential for a low friction solid lubricated bearing.

  5. Lubrication Flows.

    ERIC Educational Resources Information Center

    Papanastasiou, Tasos C.

    1989-01-01

    Discusses fluid mechanics for undergraduates including the differential Navier-Stokes equations, dimensional analysis and simplified dimensionless numbers, control volume principles, the Reynolds lubrication equation for confined and free surface flows, capillary pressure, and simplified perturbation techniques. Provides a vertical dip coating…

  6. Metal Coatings

    NASA Technical Reports Server (NTRS)

    1994-01-01

    During the Apollo Program, General Magnaplate Corporation developed process techniques for bonding dry lubricant coatings to space metals. The coatings were not susceptible to outgassing and offered enhanced surface hardness and superior resistance to corrosion and wear. This development was necessary because conventional lubrication processes were inadequate for lightweight materials used in Apollo components. General Magnaplate built on the original technology and became a leader in development of high performance metallurgical surface enhancement coatings - "synergistic" coatings, - which are used in applications from pizza making to laser manufacture. Each of the coatings is designed to protect a specific metal or group of metals to solve problems encountered under operating conditions.

  7. The PM-200 lubrication system

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1991-01-01

    Plasma sprayed composite coating of metal-bonded chromium carbide with additions of silver and thermochemically stable fluorides were previously reported to be lubricative in pin on desk bench tests from room temperature to 900 C. An early coating formulation of this type, designated as PS-200, was successfully tested as a cylinder coating in a Stirling engine at a TRRT of 760 C in a hydrogen atmosphere, and as a backup lubricant for gas bearings to 650 C. A subsequent optimization program has shown that tribological properties are further improved by increasing the solid lubricant content. The improved coating is designated as PS-212. The same powder formulation was used to make free-standing powder metallurgy (PM-212) parts by sintering or hot isostatic pressing. The process is very attractive for making parts that cannot be readily plasma sprayed such as bushings and cylinders that have small bore diameters and/or high length to diameter ratios. The properties of coatings and free-standing parts fabricated from these powders are reviewed.

  8. Robust and Drain Resistant Lubricated Omniphobic Fabrics

    NASA Astrophysics Data System (ADS)

    Kido, Cassidee; Damle, Viraj; Sun, Xiaoda; Roopesh, Ajay; Doudrick, Kyle; Rykaczewski, Konrad

    2014-11-01

    The implications of omniphobic fabrics range from stainproof clothing to civilian and military protection from chemical weapons. The challenge comes in developing a product that remains effective in repelling droplets of liquids with a wide range of surface tensions even after being subjected to various stimuli imposed by human use. Omniphobic fabrics can be made by infusing hydrophobic nanoparticle coated fibers with a low surface energy lubricant. These types of lubricant impregnated surfaces can shed large deposited droplets as well as condensed microdroplets of variety of low surface tension liquids. However, here we show that lubricated omniphobic fabrics can easily lose their properties due to degradation of the nanostructure coating or drainage of the lubricant upon contact with a porous surface. We also demonstrate that this issue can be resolved with use of cross-linked polymer coated fibers that are swollen with the lubricant. Use of flexible polymers avoids structure degradation due to fabric deformation, while swelling of the polymer with lubricant minimizes lubricant drainage upon contact maintaining the omniphobic characteristics of the fabric. KR acknowledges startup funding from ASU and collaborative effort with Dr. Tim Burgin and James R. Lee from Naval Surface Warfare Center Dahlgren Division.

  9. Tethered Lubricants

    SciTech Connect

    Archer, Lynden

    2010-09-15

    We have performed extensive experimental and theoretical studies of interfacial friction, relaxation dynamics, and thermodynamics of polymer chains tethered to points, planes, and particles. A key result from our tribology studies using lateral force microscopy (LFM) measurements of polydisperse brushes of linear and branched chains densely grafted to planar substrates is that there are exceedingly low friction coefficients for these systems. Specific project achievements include: (1) Synthesis of three-tiered lubricant films containing controlled amounts of free and pendent PDMS chains, and investigated the effect of their molecular weight and volume fraction on interfacial friction. (2.) Detailed studies of a family of hairy particles termed nanoscale organic hybrid materials (NOHMs) and demonstration of their use as lubricants.

  10. Spectroscopic Analysis of Perfluoropolyether Lubricant Degradation During Boundary Lubrication

    NASA Technical Reports Server (NTRS)

    Herrera-Fierro, Pilar; Shogrin, Bradley A.; Jones, William R., Jr.

    1996-01-01

    The degradation of a branched perfluoropolyether (PFPE) under boundary lubrication conditions was studied using mu-FTIR and mu-Raman spectroscopies. Stainless steel (440C) discs coated with thin (600A), uniform films of the PFPE were tested in a ball-on-disc apparatus until various levels of friction coefficient were attained. Discs were then examined using the above techniques. When the friction coefficient surpassed the value obtained with an un-lubricated control, the lubricant film had either been physically displaced or partially transformed in to a 'friction polymer'. Infrared analysis of this 'friction polymer' indicated the presence of a polymeric fluorinated acid species (R(sub f)COOH). Raman spectroscopy indicated the presence of amorphous carbon in the wear track and in the friction polymer. Some reaction mechanisms are suggested to explain the results.

  11. Testing and Lubrication for Single Race Bearings

    SciTech Connect

    Steinhoff, R.G.

    1998-03-04

    Three ES and H-compatible lubricants (Environment, Safety and Health) for single race bearing applications and one hybrid-material single race bearings were evaluated and compared against single race bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in stronglink mechanisms since 1974. Hybrid bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, bearings lubricated with titanium carbide (TiC) on the balls, bearings lubricated with sputtered MoS{sub 2} on races and retainers, and bearings lubricated with electrophoretically deposited MoS{sub 2} were evaluated. The bearings were maintained in a preloaded state in bearing cartridges during cycling and vibration tests. Bearings with electrophoretically deposited MoS{sub 2} performed as well as bearings lubricated with Vydax and were the best performing candidate. All candidates were suitable for low preload applications. Bearings with TiC coated balls and bearings lubricated with sputtered MoS{sub 2} on the races and retainers performed well at high preloads, though not as well as bearings lubricated with electrophoretic deposition of MoS{sub 2}. Bearings with silicon nitride balls were not suitable for high preload applications.

  12. Liquid lubrication for space applications

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.; Khonsari, Michael M.

    1992-01-01

    Reviewed here is the state of the art of liquid lubrication for space applications. The areas discussed are types of liquid lubrication mechanisms, space environmental effects on lubrication, classification of lubricants, liquid lubricant additives, grease lubrication, mechanism materials, bearing anomalies and failures, lubricant supply techniques, and application types and lubricant needs for those applications.

  13. Slippery but Tough: The Rapid Fracture of Lubricated Frictional Interfaces

    NASA Astrophysics Data System (ADS)

    Bayart, E.; Svetlizky, I.; Fineberg, J.

    2016-05-01

    We study the onset of friction for rough contacting blocks whose interface is coated with a thin lubrication layer. High speed measurements of the real contact area and stress fields near the interface reveal that propagating shear cracks mediate lubricated frictional motion. While lubricants reduce interface resistances, surprisingly they significantly increase the energy dissipated Γ during rupture. Moreover, lubricant viscosity affects the onset of friction but has no effect on Γ . Fracture mechanics provide a new way to view the otherwise hidden complex dynamics of the lubrication layer.

  14. Tribological properties of amorphous hydrogenated (a-C:H) and hydrogen-free tetrahedral (ta-C) diamond-like carbon coatings under jatropha biodegradable lubricating oil at different temperatures

    NASA Astrophysics Data System (ADS)

    Mobarak, H. M.; Masjuki, H. H.; Mohamad, E. Niza; Kalam, M. A.; Rashedul, H. K.; Rashed, M. M.; Habibullah, M.

    2014-10-01

    The application of diamond-like carbon (DLC) coatings on automotive components is emerging as a favorable strategy to address the recent challenges in the industry. DLC coatings can effectively lower the coefficient of friction (CoF) and wear rate of engine components, thereby improving their fuel efficiency and durability. The lubrication of ferrous materials can be enhanced by a large amount of unsaturated and polar components of oils. Therefore, the interaction between nonferrous coatings (e.g., DLC) and vegetable oil should be investigated. A ball-on-plate tribotester was used to run the experiments. Stainless steel plates coated with amorphous hydrogenated (a-C:H) DLC and hydrogen-free tetrahedral (ta-C) DLC that slide against 440C stainless steel ball were used to create a ball-on-plate tribotester. The wear track was investigated through scanning electron microscopy. Energy dispersive and X-ray photoelectron spectroscopies were used to analyze the tribofilm inside the wear track. Raman analysis was performed to investigate the structural changes in the coatings. At high temperatures, the CoF in both coatings decreased. The wear rate, however, increased in the a-C:H but decreased in the ta-C DLC-coated plates. The CoF and the wear rate (coated layer and counter surface) were primarily influenced by the graphitization of the coating. Tribochemical films, such as polyphosphate glass, were formed in ta-C and acted as protective layers. Therefore, the wear rate of the ta-C DLC was lower than that of the-C:H DLC.

  15. Homegrown lubricants and plastics. [Brassica

    SciTech Connect

    Senft, D.

    1988-10-01

    A small bushy lesquerella plant of the mustard family growing wild in Arizona, New Mexico, Oklahoma and Texas produces seeds that may be used to make lubricants, plastics, protective coatings, surfactants, and pharmaceuticals. The plant thrives on poor soils that receive as little as 10 inches of rain a year. Studies to date indicate that target yields can be reached with a reasonable breeding effort coupled with agronomic research.

  16. Testing and evaluation of solid lubricants for gas bearings

    NASA Technical Reports Server (NTRS)

    Albrecht, P. R.; Fischer, W. H.

    1974-01-01

    The testing and results of testing solid film lubricants for gas lubricated bearing applications are reported. The tests simulated operational hazards of tilting pad gas bearings. The presence of a low coefficient of friction and the endurance of the solid film lubricant were the criteria for judging superior performance. All solid lubricants tested were applied to a plasma sprayed chrome oxide surface. Molybdenum disulfide and graphite fluoride were the solid lubricants tested; other test parameters included the method of application of the solid lubricant and the surface finish of the plasma sprayed coating. In general, the application of a solid film lubricant was found to significantly improve the coefficient of friction of the rubbing surfaces.

  17. A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Zaldana, Antonio R.; Radil, Kevin C.

    2002-01-01

    Foil air bearings are self-acting hydrodynamic bearings which rely upon solid lubricants to reduce friction and minimize wear during sliding which occurs at start-up and shut-down when surface speeds are too low to allow the formation of a hydrodynamic air film. This solid lubrication is typically accomplished by coating the non-moving foil surface with a thin, soft polymeric film. The following paper introduces a systems approach in which the solid lubrication is provided by a combination of self lubricating shaft coatings coupled with various wear resistant and lubricating foil coatings. The use of multiple materials, each providing different functions is modeled after oil-lubricated hydrodynamic sleeve bearing technology which utilizes various coatings and surface treatments in conjunction with oil lubricants to achieve optimum performance. In this study, room temperature load capacity tests are performed on journal foil air bearings operating at 14,000 rpm. Different shaft and foil coating technologies such as plasma sprayed composites, ceramic, polymer and inorganic lubricant coatings are evaluated as foil bearing lubricants. The results indicate that bearing performance is improved through the individual use of the lubricants and treatments tested. Further, combining several solid lubricants together yielded synergistically better results than any material alone.

  18. An investigation of oxidation-resistant solid lubricant materials.

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1971-01-01

    Recent research at NASA-Lewis on solid lubricants for use at high temperatures in air and other gaseous environments is presented. The characteristics of oxide and fluoride lubricants at temperatures to 1700 F are described. Data is presented for fluoride coatings with silicate and other additives incorporated to give improved wear life and better oxidation protection to the substrate metal. Experience is described for fluoride-metal self-lubricating composites with improved metal oxidation resistance to 1700 F. The concept of cast, self-lubricating ceramics is also explored.

  19. Lubrication with solids.

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.; Johnson, R. L.

    1972-01-01

    Brief discussion of the historical background, variety range, chemistry, physics, and other properties of solid lubricants, and review of their current uses. The widespread use of solid lubricants did not occur until about 1947. At present, they are the object of such interest that a special international conference on their subject was held in 1971. They are used at temperatures beyond the useful range of conventional lubricating oils and greases. Their low volatility provides them with the capability of functioning effectively in vacuum and invites their use in space applications. Their high load carrying ability makes them useful with heavily loaded components. Solid lubricants, however, do lack some of the desirable properties of conventional lubricants. Unlike oils and greases, which have fluidity and can continuously be carried back into contact with lubricated surfaces, solid lubricants, because of their immobility, have finite lives. Also, oils and greases can carry away frictional heat from contacting surfaces, while solid lubricants cannot.

  20. Carbide/Fluoride/Silver Self-Lubricating Composite

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1987-01-01

    Bearing coatings survive at operating temperatures up to 870 degrees C. PS200 composite self-lubricating coating for bearing applications operating at temperatures above failure points of traditional solid lubricants. Excellent friction and wear performance in oxidizing atmospheres up to 1,600 degrees F and reducing atmospheres up to 1,400 degrees F. Performance needed for development of advanced heat engines as adiabatic diesel and Stirling engine.

  1. Electrophoretically-deposited solid film lubricants

    SciTech Connect

    Dugger, M.T.; Panitz, J.K.J.; Vanecek, C.W.

    1995-04-01

    An aqueous-based process that uses electrophoresis to attract powdered lubricant in suspension to a charged target was developed. The deposition process yields coatings with low friction, complies with environmental safety regulations, requires minimal equipment, and has several advantages over processes involving organic binders or vacuum techniques. This work focuses on development of the deposition process, includes an analysis of the friction coefficient of the material in sliding contact with stainless steel under a range of conditions, and a functional evaluation of coating performance in a precision mechanical device application. Results show that solid lubricant films with friction coefficients as low as 0.03 can be produced. A 0.03 friction coefficient is superior to solid lubricants with binder systems and is comparable to friction coefficients generated with more costly vacuum techniques.

  2. International Conference on Solid Lubrication, 3rd, Denver, CO, August 7-10, 1984, Proceedings

    SciTech Connect

    Not Available

    1984-01-01

    The present conference on solid lubrication technologies gives attention to such topics as graphite films and graphite motor oils, a wear equation for solid film lubricants, a built-in SEM friction tester, cupric oxide solid lubricant for copper, intercalated dichalcogenide solid lubricants, and the in situ formation of solid lubricating films from mineral oil and ester base lubricants. Also discussed are bonded solid film lubricants, motor brush wear test results, solid lubricant performance contributions to friction linings, the self-lubricating property of Fe-Mo-S alloys in vacuum, the friction of solvent-cast polymeric films, tribological processes in sliding polymer interfaces, and the application of ethyl cellulose to the cold pressure working of ferrous metals. A closing section gives attention to sputtered and ion-plated coatings.

  3. Solid Lubricant For Alumina

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Pepper, Stephen V.; Honecy, Frank S.

    1993-01-01

    Outer layer of silver lubricates, while intermediate layer of titanium ensures adhesion. Lubricating outer films of silver deposited on thin intermediate films of titanium on alumina substrates found to reduce sliding friction and wear. Films provide effective lubrication for ceramic seals, bearings, and other hot sliding components in advanced high-temperature engines.

  4. Lubrication And Wear Of Hot Ceramics

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.; Jacobson, T. P.; Deadmore, D.; Miyoshi, K.

    1988-01-01

    Report presents results of experiments on tribological properties of ceramics. Describes friction and wear characteristics of some ceramics under consideration for use in gas turbines, diesel engines, and Stirling engines. Discusses formulation of composite plasma-sprayed ceramics containing solid lubricant additives, and data for carbide- and oxide-based composite coatings for use at temperatures up to at least 900 degree C.

  5. CVD method of forming self-lubricating composites

    DOEpatents

    Besmann, Theodore M.; Blau, Peter J.; Lee, Woo Y.; Bae, Yong W.

    1998-01-01

    An article having a multiphase composite lubricant coating of a hard refractory matrix phase of titanium nitride dispersed with particles of a solid lubricating phase of molybdenum disulfide is prepared by heating the article to temperatures between 350.degree. and 850.degree. C. in a reaction vessel at a reduced pressure and passing a gaseous mixture of Ti((CH.sub.3).sub.2 N).sub.4, MoF.sub.6, H.sub.2 S and NH.sub.3 over the heated article forming a multiphase composite lubricant coating on the article.

  6. CVD method of forming self-lubricating composites

    DOEpatents

    Besmann, T.M.; Blau, P.J.; Lee, W.Y.; Bae, Y.W.

    1998-12-01

    An article having a multiphase composite lubricant coating of a hard refractory matrix phase of titanium nitride dispersed with particles of a solid lubricating phase of molybdenum disulfide is prepared by heating the article to temperatures between 350 and 850 C in a reaction vessel at a reduced pressure and passing a gaseous mixture of Ti((CH{sub 3}){sub 2}N){sub 4}, MoF{sub 6}, H{sub 2}S and NH{sub 3} over the heated article forming a multiphase composite lubricant coating on the article. 1 fig.

  7. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  8. Enhancement of Perfluoropolyether Boundary Lubrication Performance

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.; Ajayi, O. O.; Wedeven, L. D.

    1996-01-01

    A ball bearing simulator operating under starved conditions was used to perform screening tests to evaluate the boundary lubrication performance of a branched perfluoropolyether (PFPE), K-143 AB. Several approaches to enhance boundary lubrication were studied. These included: (1) soluble boundary additives, (2) bearing surface modifications, (3) 'run-in' surface films, and (4) ceramic bearing components. In addition, results were compared with two non-perfluorinated liquid lubricant formulations. Based on these tests, the following tentative conclusions can be made: (1) Substantial improvements in boundary lubrication performance were observed with a beta-diketone boundary additive and a tricresyl phosphate (TCP) liquid surface pretreatment, (2) the use of rough Si3N4 balls (R(sub a) = 40 micro-inch) also provided increases in test duration, but with concomitant abrasive wear, (3) moderate improvements were seen with two boundary additives (a phosphine and a phosphatriazine) and a neat (100%) fluid (a carboxylic acid terminated PFPE); and small improvements with surface pretreatments with synthetic hydrocarbons, a polytetrafluoroethylene (PTFE) coating, and TiC coated 440 C and smooth Si3N4 balls (R(sub a) = 1 micro-inch), and (4) two non-PFPE lubricant formulations (a polyalphaolefin (PAO) and synthetic hydrocarbon) yielded substantial improvements.

  9. Lubricant rheology applied to elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Winer, W. O.; Sanborn, D. M.

    1977-01-01

    Viscosity measurements in a high pressure rheometer, elastohydrodynamic simulator studies (including the development of a temperature measuring technique), and analytical fluid modeling for elastohydrodynamic contacts are described. The more recent research which is described concerns infrared temperature measurements in elastohydrodynamic contacts and the exploration of the glassy state of lubricants. A correlation, of engineering significance, was made between transient surface temperature measurements and surface roughness profiles. Measurements of glass transitions of lubricants and the study of the effect of rate processes on materials lead to the conclusion that typical lubricants go into the glassy state as they pass through the contact region of typical elastohydrodynamic contacts.

  10. Evaluation of chromium oxide and molybdenum disulfide coatings in self-acting stops of an air-lubricated Rayleigh step thrust bearing

    NASA Technical Reports Server (NTRS)

    Nemeth, Z. N.

    1974-01-01

    Two coatings for a Rayleigh step thrust bearing were tested when coasting down and stopping under self-acting operation in air. The thrust bearing had an outside diameter of 8.9 cm (3.5 in.), an inside diameter of 5.4 cm (2.1 in.), and nine sectors. The load was 73 N (16.4 lbf). The load pressure was 19.1 kN/per square meter (2.77 lbf/per square inch) on the total thrust bearing area. The chromium oxide coating was good to 150 stops without bearing deterioration, and the molybdenum disulfide coating was good for only four stops before bearing deterioration. The molybdenum disulfide coated bearing failed after nine stops.

  11. Industry Needs Fulfilled by Patented NASA PS300 Solid Lubricant Technology

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2003-01-01

    In 1999, the NASA Glenn Research Center was awarded a patent (#5866518) for a new high-temperature solid lubricant coating material, PS300. A combination of wear-resistant metals and ceramics with solid lubricant additives, PS300 reduces friction and wear in sliding contacts from below ambient to over 650 C. This lubricant is an outgrowth of over three decades of high-temperature tribological research and was specifically developed as a shaft lubricant to protect foil air bearings used in Oil-Free turbomachinery, like gas turbines. Foil bearings are lubricated by air at high speeds but experience sliding and wear during initial startup and shut down when a lubricating film of air has not yet developed. PS300 shaft coatings have successfully lubricated foil bearings for over 100 000 cycles without wearing out.

  12. Lubrication of Nitinol 60

    NASA Technical Reports Server (NTRS)

    Pepper, Stephen V.; DellaCorte, Christopher; Glennon, Glenn

    2010-01-01

    The mechanical properties of Nitinol 60, 60 wt% Ni, 40 wt% Ti (55 at.% Ni, 45 at.% Ti) are sufficiently attractive to warrant its consideration as a lubricated triboelement. Triboelements are always run lubricated. The ability to lubricate Nitinol 60 by the oils usually used on spacecraft mechanisms--Pennzane 2001A, Krytox 143AC and Castrol 815Z--was experimentally determined. These oils were run in the boundary lubrication regime for Nitinol 60 balls running against Nitinol 60 counterfaces in the vacuum spiral orbit tribometer. Test results consisting of the coefficient of friction versus time (friction traces) and relative degradation rates of the oils are presented. Contrary to the inability to successfully lubricate other metal alloys with high titanium content, it was found that Nitinol 60 is able to be lubricated by these oils. Overall, the results presented here indicate that Nitinol 60 is a credible candidate material for bearing applications.

  13. Boundary lubrication: Revisited

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.

    1982-01-01

    A review of the various lubrication regimes, with particular, emphasis on boundary lubrication, is presented. The types of wear debris and extent of surface damage is illustrated for each regime. The role of boundary surface films along with their modes of formation and important physical properties are discussed. In addition, the effects of various operating parameters on friction and wear in the boundary lubrication regime are considered.

  14. Fundamentals of fluid lubrication

    NASA Technical Reports Server (NTRS)

    Hamrock, Bernard J.

    1991-01-01

    The aim is to coordinate the topics of design, engineering dynamics, and fluid dynamics in order to aid researchers in the area of fluid film lubrication. The lubrication principles that are covered can serve as a basis for the engineering design of machine elements. The fundamentals of fluid film lubrication are presented clearly so that students that use the book will have confidence in their ability to apply these principles to a wide range of lubrication situations. Some guidance on applying these fundamentals to the solution of engineering problems is also provided.

  15. DIESEL FUEL LUBRICATION

    SciTech Connect

    Qu, Jun

    2012-01-01

    The diesel fuel injector and pump systems contain many sliding interfaces that rely for lubrication upon the fuels. The combination of the poor fuel lubricity and extremely tight geometric clearance between the plunger and bore makes the diesel fuel injector vulnerable to scuffing damage that severely limits the engine life. In order to meet the upcoming stricter diesel emission regulations and higher engine efficiency requirements, further fuel refinements that will result in even lower fuel lubricity due to the removal of essential lubricating compounds, more stringent operation conditions, and tighter geometric clearances are needed. These are expected to increase the scuffing and wear vulnerability of the diesel fuel injection and pump systems. In this chapter, two approaches are discussed to address this issue: (1) increasing fuel lubricity by introducing effective lubricity additives or alternative fuels, such as biodiesel, and (2) improving the fuel injector scuffing-resistance by using advanced materials and/or surface engineering processes. The developing status of the fuel modification approach is reviewed to cover topics including fuel lubricity origins, lubricity improvers, alternative fuels, and standard fuel lubricity tests. The discussion of the materials approach is focused on the methodology development for detection of the onset of scuffing and evaluation of the material scuffing characteristics.

  16. Lubrication of Machine Elements

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1984-01-01

    The understanding of hydrodynamic lubrication began with the classical experiments of Tower and Petrov. Reynolds used a reduced form of the Navier-Stokes equations and the continuity equation to generate a second order differential equation for the pressure in the narrow, converging gap of a bearing contact. Such a pressure enables a load to be transmitted between the surfaces with very low friction since the surfaces are completely separated by a film of fluid. In such a situation it is the physical properties of the lubricant, notably the dynamic viscosity, that dictate the behavior of the contact. The understanding of boundary lubrication is normally attributed to Hardy and Doubleday. In boundary lubrication it is the physical and chemical properties of thin films of molecular proportions and the surfaces to which they are attached that determine contact behavior. The lubricant viscosity is not an influential parameter. Research is devoted to a better understanding and more precise definition of other lubrication regimes between these extremes. One such regime, elastohydrodynamic lubrication, occurs in nonconformal contacts, where the pressures are high and the bearing surfaces deform elastically. In this situation the viscosity of the lubricant may raise considerably, and this further assists the formation of an effective fluid film. The science of these three lubrication regimes (hydrodynamic, elastohydrodynamic, and boundary) are described and the manner in which this science is used in the design of machine elements is examined.

  17. Carbon-based tribofilms from lubricating oils.

    PubMed

    Erdemir, Ali; Ramirez, Giovanni; Eryilmaz, Osman L; Narayanan, Badri; Liao, Yifeng; Kamath, Ganesh; Sankaranarayanan, Subramanian K R S

    2016-08-01

    Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid 'tribofilms', which together ensure easy slippage and long wear life. The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant's anti-wear additive (typically zinc dialkyldithiophosphate). Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids. Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon. Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon-carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm. PMID:27488799

  18. Ocean Spray Lubricates Winds

    ERIC Educational Resources Information Center

    Journal of College Science Teaching, 2005

    2005-01-01

    According to a new study by two University of California, Berkeley, mathematicians and their Russian colleague, the water droplets kicked up by rough seas serve to lubricate the swirling winds of hurricanes and cyclones, letting them build to speeds approaching 200 miles per hour. Without the lubricating effect of the spray, the mathematicians…

  19. Sporting Good Lubricants

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Sun Coast Chemicals was originally contracted by Lockheed Martin Space Operations to formulate a spray lubricant free of environmental drawbacks for the Mobile Launch Platform used to haul the Space Shuttle from the Kennedy Space Center Vehicle Assembly Building to a launch pad. From this work, Sun Coast introduced Train Track Lubricant, Penetrating Spray Lube, and Biodegradable Hydraulic Fluid. Based on the original lubricant work, two more products have also been introduced. First, the X-1R Super Gun Cleaner and Lubricant protects guns from rust and corrosion caused by environmental conditions. Second, the X-1R Tackle Pack, endorsed by both fresh and saltwater guides and certain reel manufacturers, penetrates, cleans, reduces friction, lubricates, and provides extra protection against rust and corrosion.

  20. Formulation of Automotive Lubricants

    NASA Astrophysics Data System (ADS)

    Atkinson, D.; Brown, A. J.; Jilbert, D.; Lamb, G.

    The formulation of lubricants for current light- and heavy-duty vehicles (passenger cars and trucks) and also motorcycles/small engines is described in terms of engine types and meeting European, US and Japanese emission control requirements. Trends in the formulation of lubricants are discussed and the importance of high and low 'SAPS' for future developments emphasised. Specification and evaluation of lubricant performance for light-vehicle gasoline and diesel, and also heavy-duty diesel engines are described. Emphasis is given to diesel engine cleanliness by soot and deposit control and the effect of emission controls on lubricant formulation. The lubricant requirements for motorcycle and small engines, primarily two-stroke cycle, and their specifications are described.

  1. Lubricant replacement in rolling element bearings for weapon surety devices

    SciTech Connect

    Steinhoff, R.; Dugger, M.T.; Varga, K.S.

    1996-05-01

    Stronglink switches are a weapon surety device that is critical to the nuclear safety theme in modem nuclear weapons. These stronglink switches use rolling element bearings which contain a lubricant consisting of low molecular weight polytetrafluoroethylene (PTFE) fragments. Ozone-depleting solvents are used in both the manufacture and application of this lubricant. An alternate bearing lubrication for stronglink switches is needed that will provide long-term chemical stability, low migration and consistent performance. Candidates that were evaluated include bearings with sputtered MoS{sub 2} on the races and retainers, bearings with TiC-coated balls, and bearings with Si{sub 3}N{sub 4} balls and steel races. These candidates were compared to the lubricants currently used which are bearings lubricated with PTFE fragments of low molecular weight in a fluorocarbon solvent. The candidates were also compared to bearings lubricated with a diester oil which is representative of bearing lubricants used in industrial applications. Evaluation consisted of cycling preloaded bearings and subjecting them to 23 gRMS random vibration. All of the candidates are viable substitutes for low load application where bearing preload is approximately 1 pound. For high load applications where the bearing preload is approximately 10 pounds, bearings with sputtered MoS{sub 2} on the races and retainers appear to be the best substitutes. Bearings with TiC-coated balls also appear to be a viable candidate but these bearings did not perform as well as the sputtered MoS{sub 2}.

  2. Innovative Die Material and Lubrication Strategies for Clean and Energy Conserving Forging Technologies

    SciTech Connect

    Rajiv Shivpuri; Sailesh Babu; Lin Yang; Yijun Zhu

    2007-01-08

    The objective of this project was to develop and implement innovative die material and surface coating strategies such as composite dies and lubricated coatings to increase die lives and to reduce environmental pollution. In this project approaches and software were developed for die life optimization and optimal design of lubrication systems for hot forging. In addition, LENS applied nickel-aluminide coatings were developed and validated in the industrial environment for significant improvements in die life.

  3. Microfriction studies of model self-lubricating surfaces

    SciTech Connect

    Blau, P.J.; Yust, C.S.

    1993-05-06

    Self-lubricating composites consist of at least one structural (matrix) phase and at least one phase to provide lubrication. Modeling the behavior of such composites involves ascertaining the frictional contributions of each constituent phase under varying conditions of lubricating films coverage. The ORNL friction microprobe (FMP), a specialized microcontact tribometer, was used to investigate the frictional behavior of both matrix and lubricant phases to support the development of self-lubricating, surfaces. Polished CVD-silicon carbide deposits and silicon wafers were used as substrates. The wafers were intended to simulate the thin silica films present on SiC surfaces at elevated temperature. Molybdenum disulfide, in both sputtered and burnished forms, was used as the model lubricant. The effects of CVD-SiC substrate surface roughness and method of lubricant film deposition on the substrate were studied for single passes of a spherical silicon nitride slider (NBD 200 material). In contrast to the smooth sliding exhibit by burnished, films, sputtered MoS{sub 2} surfaces exhibited marked stick-slip behavior, indicating that the frictional behavior of solid lubricating coatings can be quite erratic on a microscale, especially when asperity contacts are elastically compliant.

  4. Protective Coatings

    NASA Technical Reports Server (NTRS)

    1980-01-01

    General Magnaplate Corporation's pharmaceutical machine is used in the industry for high speed pressing of pills and capsules. Machine is automatic system for molding glycerine suppositories. These machines are typical of many types of drug production and packaging equipment whose metal parts are treated with space spinoff coatings that promote general machine efficiency and contribute to compliance with stringent federal sanitation codes for pharmaceutical manufacture. Collectively known as "synergistic" coatings, these dry lubricants are bonded to a variety of metals to form an extremely hard slippery surface with long lasting self lubrication. The coatings offer multiple advantages; they cannot chip, peel or be rubbed off. They protect machine parts from corrosion and wear longer, lowering maintenance cost and reduce undesired heat caused by power-robbing friction.

  5. Dairy Equipment Lubrication

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Lake To Lake Dairy Cooperative, Manitowoc, Wisconsin, operates four plants in Wisconsin for processing milk, butter and cheese products from its 1,300 member farms. The large co-op was able to realize substantial savings by using NASA information for improved efficiency in plant maintenance. Under contract to Marshall Space Flight Center, Midwest Research Institute compiled a handbook consolidating information about commercially available lubricants. The handbook details chemical and physical properties, applications, specifications, test procedures and test data for liquid and solid lubricants. Lake To Lake's plant engineer used the handbook to effect savings in maintenance labor and materials costs by reducing the number of lubricants used on certain equipment. Strict U.S. Department of Agriculture and Food and Drug Administration regulations preclude lubrication changes n production equipment, but the co-op's maintenance chief was able to eliminate seven types of lubricants for ancillary equipment, such as compressors and high pressure pumps. Handbook data enabled him to select comparable but les expensive lubricants in the materials consolidation process, and simplified lubrication schedules and procedures. The handbook is in continuing use as a reference source when a new item of equipment is purchased.

  6. Driveline Fundamentals and Lubrication

    NASA Astrophysics Data System (ADS)

    Joseph, I.

    The various gear types and automotive transmissions in drive trains are described. The need for automotive differential axle gears is demonstrated. SAE gear lubricant classifications are related to performance specifications. Automatic transmission fluids, ATFs, are described together with agricultural and off-highway fluids. Generic formulations of driveline fluids are discussed in terms of their tribology and performance and also the contribution of various additive classes to that performance. The main functions of manual gearbox, automatic transmission and axle lubricants are described. General trends and emerging technologies in drive train components are discussed in terms of the requirements placed on the lubricant, evolution in transmission technologies and relative market penetration.

  7. Carbon-based tribofilms from lubricating oils

    NASA Astrophysics Data System (ADS)

    Erdemir, Ali; Ramirez, Giovanni; Eryilmaz, Osman L.; Narayanan, Badri; Liao, Yifeng; Kamath, Ganesh; Sankaranarayanan, Subramanian K. R. S.

    2016-08-01

    Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid ‘tribofilms’, which together ensure easy slippage and long wear life. The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant’s anti-wear additive (typically zinc dialkyldithiophosphate). Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids. Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon. Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon–carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm.

  8. Carbon-based tribofilms from lubricating oils

    NASA Astrophysics Data System (ADS)

    Erdemir, Ali; Ramirez, Giovanni; Eryilmaz, Osman L.; Narayanan, Badri; Liao, Yifeng; Kamath, Ganesh; Sankaranarayanan, Subramanian K. R. S.

    2016-08-01

    Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid ‘tribofilms’, which together ensure easy slippage and long wear life. The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant’s anti-wear additive (typically zinc dialkyldithiophosphate). Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids. Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon. Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon-carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm.

  9. Molecular dynamics simulations of elasto-hydrodynamic lubrication and boundary lubrication for automotive tribology

    NASA Astrophysics Data System (ADS)

    Washizu, Hitoshi; Sanda, Shuzo; Hyodo, Shi-aki; Ohmori, Toshihide; Nishino, Noriaki; Suzuki, Atsushi

    2007-11-01

    Friction control of machine elements on a molecular level is a challenging subject in vehicle technology. We describe the molecular dynamics studies of friction in two significant lubrication regimes. As a case of elastohydrodynamic lubrication, we introduce the mechanism of momentum transfer related to the molecular structure of the hydrocarbon fluids, phase transition of the fluids under high pressure, and a submicron thickness simulation of the oil film using a tera-flops computer. For boundary lubrication, the dynamic behavior of water molecules on hydrophilic and hydrophobic silicon surfaces under a shear condition is studied. The dynamic structure of the hydrogen bond network on the hydrophilic surface is related to the low friction of the diamond-like carbon containing silicon (DLC-Si) coating.

  10. Lubrication of Articular Cartilage.

    PubMed

    Jahn, Sabrina; Seror, Jasmine; Klein, Jacob

    2016-07-11

    The major synovial joints such as hips and knees are uniquely efficient tribological systems, able to articulate over a wide range of shear rates with a friction coefficient between the sliding cartilage surfaces as low as 0.001 up to pressures of more than 100 atm. No human-made material can match this. The means by which such surfaces maintain their very low friction has been intensively studied for decades and has been attributed to fluid-film and boundary lubrication. Here, we focus especially on the latter: the reduction of friction by molecular layers at the sliding cartilage surfaces. In particular, we discuss such lubrication in the light of very recent advances in our understanding of boundary effects in aqueous media based on the paradigms of hydration lubrication and of the synergism between different molecular components of the synovial joints (namely hyaluronan, lubricin, and phospholipids) in enabling this lubrication.

  11. Liquid lubrication in space

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin V.

    1990-01-01

    The requirement for long-term, reliable operation of aerospace mechanisms has, with a few exceptions, pushed the state of the art in tribology. Space mission life requirements in the early 1960s were generally 6 months to a year. The proposed U.S. space station schedule to be launched in the 1990s must be continuously usable for 10 to 20 years. Liquid lubrication systems are generally used for mission life requirements longer than a year. Although most spacecraft or satellites have reached their required lifetimes without a lubrication-related failure, the application of liquid lubricants in the space environment presents unique challenges. The state of the art of liquid lubrication in space as well as the problems and their solutions are reviewed.

  12. Solid lubrication design methodology

    NASA Technical Reports Server (NTRS)

    Aggarwal, B. B.; Yonushonis, T. M.; Bovenkerk, R. L.

    1984-01-01

    A single element traction rig was used to measure the traction forces at the contact of a ball against a flat disc at room temperature under combined rolling and sliding. The load and speed conditions were selected to match those anticipated for bearing applications in adiabatic diesel engines. The test program showed that the magnitude of traction forces were almost the same for all the lubricants tested; a lubricant should, therefore, be selected on the basis of its ability to prevent wear of the contact surfaces. Traction vs. slide/roll ratio curves were similar to those for liquid lubricants but the traction forces were an order of magnitude higher. The test data was used to derive equations to predict traction force as a function of contact stress and rolling speed. Qualitative design guidelines for solid lubricated concentrated contacts are proposed.

  13. Lubrication by glycoprotein brushes.

    NASA Astrophysics Data System (ADS)

    Zappone, Bruno; Ruths, Marina; Greene, George W.; Israelachvili, Jacob

    2006-03-01

    Grafted polyelectrolyte brushes show excellent lubricating properties under water and have been proposed as a model to study boundary lubrication in biological system. Lubricin, a glycoprotein of the synovial fluid, is considered the major boundary lubricant of articular joints. Using the Surface Force Apparatus, we have measured normal and friction forces between model surfaces (negatively charged mica, positively charged poly-lysine and aminothiol, hydrophobic alkanethiol) bearing adsorbed layers of lubricin. Lubricin layers acts like a versatile anti-adhesive, adsorbing on all the surfaces considered and creating a repulsion similar to the force between end-grafted polymer brushes. Analogies with polymer brushes also appear from bridging experiment, where proteins molecules are end-adsorbed on two opposing surfaces at the same time. Lubricin `brushes' show good lubricating ability at low applied pressures (P<0.5MPa), especially on negatively charged surfaces like mica. At higher load, the adsorbed layers wears and fails lubricating the surfaces, while still protecting the underlying substrate from wearing. Lubricin might thus be a first example of biological polyelectrolytes providing `brush-like' lubrication and wear-protection.

  14. Auxiliary lubrication pump apparatus

    SciTech Connect

    Glesmann, H.C.; Thomas, R.G.

    1987-02-10

    This patent describes an auxiliary lubrication pump apparatus for use with a towing vehicle having an engine switch, a battery, and an interior compartment, and a towed vehicle having an automatic transmission which requires forced lubrication while being towed. The apparatus comprises: (a) a lubrication pump; (b) a transmission to pump hose connected between the automatic transmission and the lubrication pump; (c) a valve having at least one signal output and two inputs: (d) a hose means for connecting an output of the lubrication pump to one of the inputs of the valve; (e) a first outflow hose for connecting the automatic transmission to another input of the valve; (f) a second output hose for connecting the output of the valve to the automatic transmission; (g) pressure sensing means positioned to sense pressure as regards the second outflow hose; and (h) control means responsive to the pressure sensing means and having switch means for providing electricity to the lubrication pump and to provide an alarm whenever the control means detects through the pressure sensing means that inadequate pressure exists.

  15. Methods to improve lubricity of fuels and lubricants

    SciTech Connect

    Erdemir, Ali

    2009-06-16

    A method for providing lubricity in fuels and lubricants includes adding a boron compound to a fuel or lubricant to provide a boron-containing fuel or lubricant. The fuel or lubricant may contain a boron compound at a concentration between about 30 ppm and about 3,000 ppm and a sulfur concentration of less than about 500 ppm. A method of powering an engine to minimize wear, by burning a fuel containing boron compounds. The boron compounds include compound that provide boric acid and/or BO.sub.3 ions or monomers to the fuel or lubricant.

  16. Power system with an integrated lubrication circuit

    DOEpatents

    Hoff, Brian D.; Akasam, Sivaprasad; Algrain, Marcelo C.; Johnson, Kris W.; Lane, William H.

    2009-11-10

    A power system includes an engine having a first lubrication circuit and at least one auxiliary power unit having a second lubrication circuit. The first lubrication circuit is in fluid communication with the second lubrication circuit.

  17. Lubrication of Space Systems (c)

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1995-01-01

    This article presents an overview of the current state-of-the-art tribology, some current and future perceived space lubrication problem areas, and some potential new lubrication technologies. It is the author's opinion that tribology technology, in general, has not significantly advanced over the last 20 to 30 years, even though some incremental improvements in the technology have occurred. There is a better understanding of elasto-hydrodynamic lubrication, some new lubricating and wear theories have been developed, and some new liquid and solid lubricants have been formulated. However, the important problems of being able to lubricate reliably at high temperatures or at cryogenic temperatures have not been adequately address.

  18. The experimental evaluation and application of high-temperature solid lubricants

    SciTech Connect

    DellaCorte, C.

    1990-01-01

    This dissertation describes a research program meant to develop an understanding of high-tenperature solid lubrication and experimental techniques through the development of a composite lubricant coating system. The knowledge gained through this research was then applied to a specific engineering challenge, the tribology of a sliding seal for hypersonic flight vehicles. The solid lubricant coating is a chromium carbide based composite combined with silver, which acts as a low temperature lubricant, and barium fluoride/calcium fluoride eutectic, which acts as a high temperature lubricant. This composite coating provides good wear resistance and low friction for sliding contacts from room temperature to over 900{degree}C in reducing or oxidative environments. The specific research on this coating included a composition screening using a foil gas bearing test rig and the use of thin silver films to reduce initial wear using a pin-on-disk test rig. The chemical stability of the materials used was also addressed. This research indicated that soft metallic films and materials which become soft at elevated temperatures are potentially good lubricants. The general results from the experiments with the model solid lubricant coating were then applied to a sliding seal design concept. This seal design requires that a braided ceramic fabric slide against a variety of metal counterface materials at temperatures from 25 to 850{degree}C in an oxidative environment. A pin-on-disk tribometer was used to evaluate the tribological properties of these materials and to develop lubrication techniques. The results of this work indicate that these seal materials must be lubricated to prevent wear and reduce fiction. Thin films of silver, gold and calcium fluoride provided lubrication to the sliding materials. 22 refs., 33 figs., 12 tabs.

  19. Fluid lubricated bearing assembly

    DOEpatents

    Boorse, Henry A.; Boeker, Gilbert F.; Menke, John R.

    1976-01-01

    1. A support for a loaded rotatable shaft comprising in combination on a housing having a fluid-tight cavity encasing an end portion of said shaft, a thrust bearing near the open end of said cavity for supporting the axial thrust of said shaft, said thrust bearing comprising a thrust plate mounted in said housing and a thrust collar mounted on said shaft, said thrust plate having a central opening the peripheral portion of which is hermetically sealed to said housing at the open end of said cavity, and means for supplying a fluid lubricant to said thrust bearing, said thrust bearing having a lubricant-conducting path connecting said lubricant supplying means with the space between said thrust plate and collar intermediate the peripheries thereof, the surfaces of said plate and collar being constructed and arranged to inhibit radial flow of lubricant and, on rotation of said thrust collar, to draw lubricant through said path between the bearing surfaces and to increase the pressure therebetween and in said cavity and thereby exert a supporting force on said end portion of said shaft.

  20. Computational Chemistry and Lubrication

    NASA Technical Reports Server (NTRS)

    Zehe, Michael J.

    1998-01-01

    Members of NASA Lewis Research Center's Tribology and Surface Science Branch are applying high-level computational chemistry techniques to the development of new lubrication systems for space applications and for future advanced aircraft engines. The next generation of gas turbine engines will require a liquid lubricant to function at temperatures in excess of 350 C in oxidizing environments. Conventional hydrocarbon-based lubricants are incapable of operating in these extreme environments, but a class of compounds known as the perfluoropolyether (PFAE) liquids (see the preceding illustration) shows promise for such applications. These commercially available products are already being used as lubricants in conditions where low vapor pressure and chemical stability are crucial, such as in satellite bearings and composite disk platters. At higher temperatures, however, these compounds undergo a decomposition process that is assisted (catalyzed) by metal and metal oxide bearing surfaces. This decomposition process severely limits the applicability of PFAE's at higher temperatures. A great deal of laboratory experimentation has revealed that the extent of fluid degradation depends on the chemical properties of the bearing surface materials. Lubrication engineers would like to understand the chemical breakdown mechanism to design a less vulnerable PFAE or to develop a chemical additive to block this degradation.

  1. Space Station lubrication considerations

    NASA Technical Reports Server (NTRS)

    Leger, Lubert J.; Dufrane, Keith

    1987-01-01

    Future activities in space will require the use of large structures and high power availability in order to fully exploit opportunities in Earth and stellar observations, space manufacturing and the development of optimum space transportation vehicles. Although these large systems will have increased capabilities, the associated development costs will be high, and will dictate long life with minimum maintenance. The Space Station provides a concrete example of such a system; it is approximately one hundred meters in major dimensions and has a life requirement of thirty years. Numerous mechanical components will be associated with these systems, a portion of which will be exposed to the space environment. If the long life and low maintenance goals are to be satisfied, lubricants and lubrication concepts will have to be carefully selected. Current lubrication practices are reviewed with the intent of determining acceptability for the long life requirements. The effects of exposure of lubricants and lubricant binders to the space environment are generally discussed. Potential interaction of MoS2 with atomic oxygen, a component of the low Earth orbit environment, appears to be significant.

  2. Engine lubricating system

    SciTech Connect

    Kurio, N.; Yoshimi, H.; Shigemura, T.; Shono, Y.

    1988-10-04

    This patent describes engine lubricating system comprising a lubricating oil supply means having a plunger member adapted to be reciprocated in the axial direction in response to an engine output shaft to discharge lubricating oil, a control pin which is adapted to abut against the plunger member and is movable to change the stroke of the plunger member, thereby changing the amount of the lubricating oil to be discharged in each stroke of the plunger member, and an electric actuator which moves the control pin to change the stroke of the plunger member; a control means which receives the electric signal from the operating condition detecting means and outputs an electric control signal for controlling the electric actuator; the actuator comprising a stepping motor and the control means outputting an electric control signal representing the number of steps by which the stepping motor is to be operated; the operating condition detecting means comprising an intake volume detecting means which detects the amount of intake air introduced into the cylinder of the engine per one engine revolution, and the control means outputs and electric signal to the stepping motor which controls the stepping motor to drive the control pin to increase the amount of the lubricating oil to be discharged in each stroke of the plunger member as the amount of intake air increases.

  3. Space Coatings for Industry

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Ball Aerospace developed entirely new space lubrication technologies. A new family of dry lubricants emerged from Apollo, specifically designed for long life in space, together with processes for applying them to spacecraft components in microscopically thin coatings. Lubricants worked successfully on seven Orbiting Solar Observatory flights over the span of a decade and attracted attention to other contractors which became Ball customers. The company has developed several hundred variations of the original OSO technology generally designed to improve the quality and useful life of a wide range of products or improve efficiency of the industrial processes by which such products are manufactured.

  4. Lubrication for high load duplex bearings

    SciTech Connect

    Steinhoff, R.G.

    1997-08-01

    Three ES and H-compatible lubricants (Environment, Safety and Health) for high load duplex bearing applications were evaluated and compared against trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon) which is an ozone-depleting solvent. Bearings with Supercritical CO{sub 2} deposition of PTFE extracted from Vydax AR/IPA, bearings with titanium carbide coated balls, and bearings with diamond-like carbon races and retainers were evaluated. Bearings with Supercritical CO{sub 2} deposition of PTFE from Vydax AR/IPA performed as well as bearings with Freon deposition of PTFE from Freon-based Vydax.

  5. Basic lubrication equations

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1981-01-01

    Lubricants, usually Newtonian fluids, are assumed to experience laminar flow. The basic equations used to describe the flow are the Navier-Stokes equation of motion. The study of hydrodynamic lubrication is, from a mathematical standpoint, the application of a reduced form of these Navier-Stokes equations in association with the continuity equation. The Reynolds equation can also be derived from first principles, provided of course that the same basic assumptions are adopted in each case. Both methods are used in deriving the Reynolds equation, and the assumptions inherent in reducing the Navier-Stokes equations are specified. Because the Reynolds equation contains viscosity and density terms and these properties depend on temperature and pressure, it is often necessary to couple the Reynolds with energy equation. The lubricant properties and the energy equation are presented. Film thickness, a parameter of the Reynolds equation, is a function of the elastic behavior of the bearing surface. The governing elasticity equation is therefore presented.

  6. Fluid lubricated bearing construction

    DOEpatents

    Dunning, John R.; Boorse, Henry A.; Boeker, Gilbert F.

    1976-01-01

    1. A fluid lubricated thrust bearing assembly comprising, in combination, a first bearing member having a plain bearing surface, a second bearing member having a bearing surface confronting the bearing surface of said first bearing member and provided with at least one spiral groove extending inwardly from the periphery of said second bearing member, one of said bearing members having an axial fluid-tight well, a source of fluid lubricant adjacent to the periphery of said second bearing member, and means for relatively rotating said bearing members to cause said lubricant to be drawn through said groove and to flow between said bearing surfaces, whereby a sufficient pressure is built up between said bearing surfaces and in said well to tend to separate said bearing surfaces.

  7. Inserts Automatically Lubricate Ball Bearings

    NASA Technical Reports Server (NTRS)

    Hager, J. A.

    1983-01-01

    Inserts on ball-separator ring of ball bearings provide continuous film of lubricant on ball surfaces. Inserts are machined or molded. Small inserts in ball pockets provide steady supply of lubricant. Technique is utilized on equipment for which maintenance is often poor and lubrication interval is uncertain, such as household appliances, automobiles, and marine engines.

  8. Environmental Capability of Liquid Lubricants

    NASA Technical Reports Server (NTRS)

    Beerbower, A.

    1973-01-01

    The methods available for predicting the properties of liquid lubricants from their structural formulas are discussed. The methods make it possible to design lubricants by forecasting the results of changing the structure and to determine the limits to which liquid lubricants can cope with environmental extremes. The methods are arranged in order of their thermodynamic properties through empirical physical properties to chemical properties.

  9. Use of Lubricants in the NIF

    SciTech Connect

    Gourdin, W; Biltoft, P

    2006-07-06

    There are two principal concerns that govern the use of lubricants in NIF: (1) Airborne molecular contaminants (AMCs)--AMCs are known to seriously degrade the performance of sol-gel coated optics. AMCs are produced by the slow outgassing of residues (non-volatile residues or ''NVRs'') of high molecular weight compounds left on surfaces. Lubricants, particularly hydrocarbon lubricants, are a primary source of such NVRs. (2) Particulates--Particulates that accumulate on optical surfaces can cause permanent physical damage when exposed to high energy density laser light. Lubricant residues exposed to high energy density light will pyrolyze or decompose and produce carbon particulates. The NIF Approved Materials Database lists several lubricants that have been tested for use in NIF environments. Many of these lubricants were tested according to MELs 99-006 (oven outgassing test) or 99-007 (vacuum outgassing test). In these tests, the change in percent transmission of light through a sol-gel coated optic placed next to the sample under evaluation is used as the diagnostic. Samples that cause less than 0.1% change in optical transmission are deemed suitable for use inside beam enclosures. This testing, however, addresses only the concern associated with AMCs. To assess the issue of particle generation, a flashlamp or ''aerosol'' test is used. In this test a sample with residues is subjected to intense light from the main amplifier flashlamps. The number density of particles per unit volume is measure after each flash. A measurement of an average of fewer than 1000 particles >0.5{micro}m in diameter produced per square foot of exposed surface per flash for each of the last ten flashes in a series of 60 flashes of light is deemed to be acceptable for polymers. A measurement of an average of fewer than 100 particles >0.5{micro}m in diameter produced per square foot of exposed surface per flash for each of the last ten flashes in a series of 60 flashes of light is deemed to

  10. Enhanced lubrication on tissue and biomaterial surfaces through peptide-mediated binding of hyaluronic acid.

    PubMed

    Singh, Anirudha; Corvelli, Michael; Unterman, Shimon A; Wepasnick, Kevin A; McDonnell, Peter; Elisseeff, Jennifer H

    2014-10-01

    Lubrication is key for the efficient function of devices and tissues with moving surfaces, such as articulating joints, ocular surfaces and the lungs. Indeed, lubrication dysfunction leads to increased friction and degeneration of these systems. Here, we present a polymer-peptide surface coating platform to non-covalently bind hyaluronic acid (HA), a natural lubricant in the body. Tissue surfaces treated with the HA-binding system exhibited higher lubricity values, and in vivo were able to retain HA in the articular joint and to bind ocular tissue surfaces. Biomaterials-mediated strategies that locally bind and concentrate HA could provide physical and biological benefits when used to treat tissue-lubricating dysfunction and to coat medical devices.

  11. Enhanced lubrication on tissue and biomaterial surfaces through peptide-mediated binding of hyaluronic acid

    NASA Astrophysics Data System (ADS)

    Singh, Anirudha; Corvelli, Michael; Unterman, Shimon A.; Wepasnick, Kevin A.; McDonnell, Peter; Elisseeff, Jennifer H.

    2014-10-01

    Lubrication is key for the efficient function of devices and tissues with moving surfaces, such as articulating joints, ocular surfaces and the lungs. Indeed, lubrication dysfunction leads to increased friction and degeneration of these systems. Here, we present a polymer-peptide surface coating platform to non-covalently bind hyaluronic acid (HA), a natural lubricant in the body. Tissue surfaces treated with the HA-binding system exhibited higher lubricity values, and in vivo were able to retain HA in the articular joint and to bind ocular tissue surfaces. Biomaterials-mediated strategies that locally bind and concentrate HA could provide physical and biological benefits when used to treat tissue-lubricating dysfunction and to coat medical devices.

  12. Dry Lubricant Smooths the Way for Space Travel, Industry

    NASA Technical Reports Server (NTRS)

    2015-01-01

    Reviving industry standards for coating parts in tungsten disulfide, a dry lubricant developed for the Mariner space probes managed by the Jet Propulsion Laboratory in the 1960s and '70s, Applied Tungstenite, a relatively new Temecula, California-based company, has found a client base in the mushrooming commercial space industry, as well as other manufacturers.

  13. A study of lubrication, processing conditions, and material combinations that affect the wear of micro-textured-carbide coated cobalt-chromium-molybdenum alloy surfaces used for artificial joints implants

    NASA Astrophysics Data System (ADS)

    Ettienne-Modeste, Geriel A.

    Total joint replacement remains one of the most successful treatments for arthritis. The most common materials used for artificial joints are metals (e.g., cobalt-chrome alloys or titanium alloys), which articulate against ultra-high molecular weight polyethylene. Wear related failures of artificial joints may be reduced with the use of novel micro-textured carbide surfaces. The micro-textured carbide surfaces were deposited on a CoCrMo alloy using microwave plasma-assisted chemical vapor deposition. Wear tests were conducted to determine wear mechanisms and properties of the micro-textured surfaces. The research presented in this thesis addresses: (1) rheolgoical behavior of bovine calf serum with and without antibacterial agents to determine whether they can be used as appropriate models for synovial fluid, (2) the wear behavior of the micro-textured CoCrMo surface system, and (3) the mechanical and material properties of the micro-textured CoCrMo alloy surface relevant to wear performance. The rheological studies showed that the apparent viscosity of bovine calf serum increased with an increase in concentration before and after the serum was used for wear testing. The wear analysis showed that the processing conditions (2hr deposition vs. 4hr deposition times) affected the wear properties. The 2hr carbide-on-carbide lubricated in 50% BCS produced the lowest wear factor and rate for the five wear couple systems containing the carbide disk or plate material. Greater wear was produced in serum without penicillin/streptomycin (P/S) compared to the serum containing P/S. A greater carbide coating thickness 10 (micrometers) was produced during the 4hr deposition time than for the 2hr deposition (˜3mum). The nano-hardness value was higher than the micro-hardness for both the 4hr and 2hr carbide surfaces. The micro-hardness results of the worn carbide surfaces showed that an increase in BCS concentration from 0% to 100% increased the micro-hardness (HV) for carbide

  14. A new solid lubricant

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.; Sliney, H. E.

    1969-01-01

    Friction and wear life studies on burnished films of the compound graphite fluoride have demonstrated its potential as a solid lubricant material. It is effective in moist air, dry air, or in dry argon at temperatures up to approximately 400 degrees C.

  15. Estolides: biobased lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estolides were originally developed as a cost effective derivative from vegetable oil sources to overcome the problems associated with standard vegetable oils as lubricants. Classic estolides are formed by the formation of a carbocation at the site of unsaturation that can undergo nucleophilic addi...

  16. Biobased lubricant additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fully biobased lubricants are those formulated using all biobased ingredients, i.e. biobased base oils and biobased additives. Such formulations provide the maximum environmental, safety, and economic benefits expected from a biobased product. Currently, there are a number of biobased base oils that...

  17. Glass microsphere lubrication

    NASA Technical Reports Server (NTRS)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  18. Enhancement of perfluoropolyether boundary lubrication performance: I. Preliminary results

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.; Ajayi, O. O.; Goodell, A. J.; Wedeven, L. D.; Devine, E.; Premore, R. E.

    1995-01-01

    A ball bearing simulator operating under starved conditions was used to evaluate the boundary lubrication performance of a perfluoropolyether (PFPE) Krytox 143 AB. Several approaches to enhance boundary lubrication were studied. These included: (1) soluble boundary additives, (2) bearing surface modifications, (3) 'run-in' surface films, and (4) ceramic bearing components. In addition, results were compared with two non-perfluorinated liquid lubricant formulations. Based on these preliminary tests, the following tentative conclusions can be made: (1) substantial improvements in boundary lubrication performance were observed with a beta-diketone boundary additive and a tricresyl phosphate (TCP) liquid surface pretreatment; (2) the use of rough Si3N4 balls (Ra = 40 micro-in) also provided substantial improvement but with concomitant abrasive wear; (3) marginal improvements were seen with two boundary additives (a phosphine and a phosphatriazine) and a neat (100%) fluid (a carboxylic acid terminated PFPE); and surface pretreatments with a synthetic hydrocarbon, a PTFE coating, and TiC coated 440C and smooth Si3N4 balls (R(sub a) less than 1 micro-in); and (4) two non-PFPE lubricant formulations (a PAO and a synthetic hydrocarbon) yielded substantial improvements.

  19. ES and H-compatible lubrication for duplex bearings

    SciTech Connect

    Steinhoff, R.G.

    1997-10-01

    Two ES and H-compatible lubricants (environment, safety, and health) for duplex bearing applications and one hybrid material duplex bearing were evaluated and compared against duplex bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in strong link mechanisms since 1974. Hybrid duplex bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, duplex bearings lubricated with sputtered MoS{sub 2} on races and retainers, and duplex bearings lubricated with electrophoretic deposited MoS{sub 2} were evaluated. Bearings with electrophoretic deposited MoS{sub 2} performed as well as bearings with Freon deposition of PTFE from Freon-based Vydax. Hybrid bearings with silicon nitride balls performed worse than bearings lubricated with Vydax, but their performance would still be acceptable for most applications. Bearings lubricated with sputtered MoS{sub 2} on the races and retainers had varying amounts of film on the bearings. This affected the performance of the bearings. Bearings with a uniform coating performed to acceptable levels, but bearings with no visible MoS{sub 2} on the races and retainers did not perform as well as bearings with the other coatings. Unless process controls are incorporated in the sputtering process or the bearings are screened, they do not appear to be acceptable for duplex bearing applications.

  20. A New Antiwear Additive/Surface Pretreatment for PFPE Liquid Lubricants

    NASA Technical Reports Server (NTRS)

    Morales, Wilfredo; Fusaro, Robert L.; Siebert, Mark; Keith, Theo; Jansen, Ralph; Herrera-Fierro, Pilar

    1995-01-01

    Pin-on-disk tribology experiments were conducted on a perfluoroalkylelher (PFPE) liquid lubricant with and without a new PFPE lubricant antiwear additive material, a silane. It was found that the silane provided moderate improvement in the antiwear performance of the PFPE lubricant when applied to the metallic surface as a surface coating or when added to the PFPE as a dispersion (emulsion). Slightly better results were obtained by using the combination of a surface coating and an emulsion of the silane. The silane emulsions or coatings did not affect the friction properties of the lubricant. Micro-Fourier transformation infrared (muFTIR) spectroscopy analysis was performed to study silane transfer films and the degradation of the PFPE. The silane was found to mitigate degradation of the PFPE which may have been the major reason for the improved antiwear performance observed.

  1. Surgical glove lubricants: from toxicity to opportunity.

    PubMed

    Woods, J A; Morgan, R F; Watkins, F H; Edlich, R F

    1997-01-01

    In most emergency departments, surgical gloves are coated with surface powders that act as lubricants to facilitate donning. Cornstarch powder is an absorbable powder employed as a donning agent on most powdered gloves. Talcum powder, a nonabsorbable powder, is used as a mold release agent in glove manufacture and is still commonly found on the surfaces of modern surgical gloves. These powders are foreign bodies that elicit inflammatory responses, leading to a wide number of symptoms and complications. The best method of preventing clinical complications from glove powder is to use powder-free gloves.

  2. Lubrication handbook for the space industry. Part A: Solid lubricants. Part B: Liquid lubricants

    NASA Technical Reports Server (NTRS)

    Mcmurtrey, E. L.

    1985-01-01

    This handbook is intended to provide a ready reference for many of the solid and liquid lubricants used in the space industry. Lubricants and lubricant properties are arranged systematically so that designers, engineers, and maintenance personnel can conveniently locate data needed for their work. This handbook is divided into two major parts (A and B). Part A is a compilation of solid lubricant suppliers information on chemical and physical property of data of more than 250 solid lubricants, bonded solid lubricants, dispersions, and composites. Part B is a compilation of chemical and physical porperty data of more then 250 liquid lubricants, greases, oils, compounds, and fluids. The listed materials cover a broad spectrum from manufacturing and ground support to hardware applications of spacecraft.

  3. Lubrication Handbook For The Space Industry

    NASA Technical Reports Server (NTRS)

    Mcmurtrey, Ernest L.

    1988-01-01

    A 458-page handbook covers many of solid and liquid lubricants used in space industry. Also useful reference in industrial and military applications of lubricants. Part A of handbook compilation of data on chemical and physical properties of over 250 solid lubricants, including bonded solid lubricants, dispersions, and composites. Part B covers over 250 liquid lubricants, greases, oils, compounds, and fluids.

  4. Quality control of the tribological coating PS212

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Dellacorte, Christopher; Deadmore, Daniel L.

    1989-01-01

    PS212 is a self-lubricating, composite coating that is applied by the plasma spray process. It is a functional lubricating coating from 25 C (or lower) to 900 C. The coating is prepared from a blend of three different powders with very dissimilar properties. Therefore, the final chemical composition and lubricating effectiveness of the coatings are very sensitive to the process variables used in their preparation. Defined here are the relevant variables. The process and analytical procedures that will result in satisfactory tribological coatings are discussed.

  5. Enhanced slippery behavior and stability of lubricating fluid infused nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Pant, Reeta; Ujjain, Sanjeev Kumar; Nagarajan, Arun Kumar; Khare, Krishnacharya

    2016-07-01

    Stability of lubricating fluid infused slippery surfaces is a concern for scientists and engineers and attempts are being made for its improvement. Lubricating oil coated slippery surface for aqueous drops is one of the important candidates in this class and their stability needs be improved to make them useful for practical applications. Cloaking of water drops with thin lubricant layer results in the loss of lubricant leading to deterioration of slippery behavior. Surface roughness or porosity provides larger surface area to the lubricating fluid and would to affect the stability of the lubricating film. Here we report the effect of surface roughness, from tens of nanometer to few microns, on the stability of slippery surface. Samples with small nanoscale roughness show improved performance in terms of contact angle hysteresis, critical tilt angle and slip velocity. Whereas large roughness samples show poorer performance compared to small nanoscale roughness and smooth samples. Small nanoscale roughness samples also show relatively slower deterioration against loss of lubricant during water flow. Once completely lost, the slippery behavior can be restored again simply by coating the sample again by the lubricating fluid.

  6. Lubrication of space systems

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1994-01-01

    NASA has many high-technology programs plannned for the future, such as the space station, Mission to Planet Earth (a series of Earth-observing satellites), space telescopes, and planetary orbiters. These missions will involve advanced mechanical moving components, space mechanisms that will need wear protection and lubrication. The tribology practices used in space today are primarily based on a technology that is more than 20 years old. The question is the following: Is this technology base good enough to meet the needs of these future long-duration NASA missions? This paper examines NASA's future space missions, how mechanisms are currently lubricated, some of the mechanism and tribology challenges that may be encountered in future missions, and some potential solutions to these future challenges.

  7. Buckyball additives improve lubrication

    SciTech Connect

    1996-08-31

    When researchers discovered the buckminsterfullerene molecule in 1985, it was considered the ideal candidate for reducing friction between tiny moving components. However, subsequently buckyballs were discovered not to be particularly good lubricators. Now, a team of chemical engineers and chemists has discovered that C60 molecules dissolved in the organic solvent toluene greatly reduce the friction between the liquid and the surface across which it flows.

  8. Shearing stability of lubricants

    NASA Technical Reports Server (NTRS)

    Shiba, Y.; Gijyutsu, G.

    1984-01-01

    Shearing stabilities of lubricating oils containing a high mol. wt. polymer as a viscosity index improver were studied by use of ultrasound. The oils were degraded by cavitation and the degradation generally followed first order kinetics with the rate of degradation increasing with the intensity of the ultrasonic irradiation and the cumulative energy applied. The shear stability was mainly affected by the mol. wt. of the polymer additive and could be determined in a short time by mechanical shearing with ultrasound.

  9. Selective Surface Modification on Lubricant Retention

    NASA Astrophysics Data System (ADS)

    Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A.

    2016-11-01

    While surface patterns are effective in improving tribological properties, nevertheless they alter the surface wettability, which will in turn affect the surface-lubricant interactions. When there is a shortage of lubricant on a patterned surface, the lubricant stored inside the cavities will be extracted to compensate the surface lubricant dissipation. Additionally, the lubricant retention effect provided by the cavities is competing with the release of the lubricant. With weak surface-lubricant interaction, the retention is limited. Therefore, the lubrication will have a sudden failure, giving a dramatic transition to abrasive wear. To improve the performance of polar lubricants on hydrophobic polymer surfaces, both topographical and selective surface modifications were incorporated on injection molded polypropylene surfaces. Distinctive lubrication improvement was observed when the surface structure density for the lubricant storage was high, and the release of the lubricant was controlled by the interaction with the selectively modified surfaces.

  10. Lubrication handbook for use in the space industry. Part A: Solid lubricants. Part B: Liquid lubricants

    NASA Technical Reports Server (NTRS)

    Campbell, M. E.; Thompson, M. B.

    1972-01-01

    This handbook provides a ready reference for many of the solid and liquid lubricants used in the space industry. Lubricants and lubricant properties are arranged systematically so that designers, engineers, and maintenance personnel in the space industry can conveniently locate data needed for their work. The handbook is divided into two major parts. Part A is a compilation of chemical and physical property data of more than 250 solid lubricants, bonded solid lubricants, dispersions and composites. Part B is a compilation of chemical and physical property data of more than 250 liquid lubricants, greases, oils, compounds and fluids. The listed materials cover a broad spectrum, from manufacturing and ground support to hardware applications for missiles and spacecraft.

  11. Coating of plasma polymerized film

    NASA Technical Reports Server (NTRS)

    Morita, S.; Ishibashi, S.

    1980-01-01

    Plasma polymerized thin film coating and the use of other coatings is suggested for passivation film, thin film used for conducting light, and solid body lubrication film of dielectrics of ultra insulators for electrical conduction, electron accessories, etc. The special features of flow discharge development and the polymerized film growth mechanism are discussed.

  12. Physical Mechanisms of Failure, Ultralow Partial Pressure Lubrication, and the Reservoir Effect in MEMS

    NASA Astrophysics Data System (ADS)

    Hook, David Adam

    The aim of this work is to examine the effectiveness of self-assembled monolayer (SAM) coatings as long term lubrication coatings in microsystems, to examine the failure regimes of SAM coated devices, to examine the role of mobility in adsorbed lubricating films, and to examine evolution of the coefficient of friction of devices surrounded by ultralow partial pressures of alcohols up to saturation. Finally the role of self assembled monlayers in vapor phase lubrication is examined. Self-assembled monolayers are ubiquitous in fabrication of free-standing microdevices because of their ability to prevent release related and dormancy related stiction. However their ability to lubricate under sliding and normal contact conditions is not well documented. It can be shown that the energy dissipated per unit area in one sliding cycle due to friction is significant under general loading conditions. Therefore from an energy dissipated standpoint the bond energies of the silane molecules should not be enough to withstand even a short number of cycles. An extension of this is the energy imparted to the surface through a normal loading cycle through a loss of kinetic energy. It can also be shown that this is enough to break the silicon oxygen bonds however this is over a longer time scale than in sliding. Also there is an open question on the role of mobile and non-mobile adsorbed species on friction. Is the mobility of a molecule/layer on a surface an indicator of the effectiveness of the lubrication potential of the layer? Do submonolayer coverages of alcohols "lock-up" to contacting surfaces by disrupting non-corrogated potentials? Is there a distinct lowering of frictional forces at the formation of a monolayer? Controlled adsorption of mobile and non-mobile species on rubbing contacts is necessary to elucidate this physical relationship. To accomplish this one must take into account that friction measurements are highly scale dependant. Therefore to ensure the accuracy of

  13. How to evaluate solid lubricant films using a Pin-on-disk tribometer

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1987-01-01

    Over the years, the author has evaluated and compared hundreds of solid lubricant films using a Pin-on-disk tribometer. The intent of this paper is to describe to the reader experimental techniques and some of the parameters that have been observed to be important for the evaluation and development of new solid lubricant films. Pin-on-disk tribometers will be described and discussed as will experimental methods for evaluating solid lubricant materials. Methods of preparing surfaces for the coating of the thin films and different methods for applying the films will be reviewed. Factors that affect solid lubricant performance will also be discussed. Two different macroscopic mechanisms of solid lubricant film wear exist. These will be characterized schematically, and methods of measuring wear will be examined.

  14. How to evaluate solid lubricant films using a pin-on-disk tribometer

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1986-01-01

    Over the years, the author has evaluated and compared hundreds of solid lubricant films using a pin-on-disk tribometer. The intent of this paper is to describe to the reader experimental techniques and some of parameters that have been observed to be important for the evaluation and development of new solid lubricant films. Pin-on-disk tribometers will be described and discussed as will experimental methods for evaluating solid lubricant materials. Methods of preparing surfaces for the coating of the thin films and different methods for applying the films will be reviewed. Factors that affect solid lubricant performance will also be discussed. Two different macroscopic mechanisms of solid lubricant film wear exist. These will be characterized schematically, and methods of measuring wear will be examined.

  15. Process for preparing lubricating oil from used waste lubricating oil

    DOEpatents

    Whisman, Marvin L.; Reynolds, James W.; Goetzinger, John W.; Cotton, Faye O.

    1978-01-01

    A re-refining process is described by which high-quality finished lubricating oils are prepared from used waste lubricating and crankcase oils. The used oils are stripped of water and low-boiling contaminants by vacuum distillation and then dissolved in a solvent of 1-butanol, 2-propanol and methylethyl ketone, which precipitates a sludge containing most of the solid and liquid contaminants, unspent additives, and oxidation products present in the used oil. After separating the purified oil-solvent mixture from the sludge and recovering the solvent for recycling, the purified oil is preferably fractional vacuum-distilled, forming lubricating oil distillate fractions which are then decolorized and deodorized to prepare blending stocks. The blending stocks are blended to obtain a lubricating oil base of appropriate viscosity before being mixed with an appropriate additive package to form the finished lubricating oil product.

  16. KSC lubricant testing program. [lubrication characteristics and corrosion resistance

    NASA Technical Reports Server (NTRS)

    Lockhart, B. J.; Bryan, C. J.

    1973-01-01

    A program was conducted to evaluate the performance of various lubricants in use and considered for use at Kennedy Space Center (KSC). The overall objectives of the program were to: (1) determine the lubrication characteristics and relative corrosion resistance of lubricants in use and proposed for use at KSC; (2) identify materials which may be equivalent to or better than KELF-90 and Krytox 240 AC greases; and (3) identify or develop an improved lubricating oil suitable for use in liquid oxygen (LOX) pumps at KSC. It was concluded that: (1) earth gel thickened greases are very poor corrosion preventive materials in the KSC environment; (2) Halocarbon 25-5S and Braycote 656 were suitable substiutes for KELF-90 and Krytox 240 AC respectively; and (3) none of the oils evaluated possessed the necessary inertness, lubricity, and corrosion prevention characteristics for the KSC LOX pumping systems in their present configuration.

  17. A Preliminary Study on the Vapor/Mist Phase Lubrication of a Spur Gearbox

    NASA Technical Reports Server (NTRS)

    Morales, Wilfredo; Handschuh, Robert F.

    1999-01-01

    Organophosphates have been the primary compounds used in vapor/mist phase lubrication studies involving ferrous bearing material. Experimental results have indicated that the initial formation of an iron phosphate film on a rubbing ferrous surface, followed by the growth (by cationic diffusion) of a lubricious pyrophosphate-type coating over the iron phosphate, is the reason organophosphates work well as vapor/mist phase lubricants. Recent work, however, has shown that this mechanism leads to the depletion of surface iron atoms and to eventual lubrication failure. A new organophosphate formulation was developed which circumvents surface iron depletion. This formulation was tested by generating an iron phosphate coating on an aluminum surface. The new formulation was then used to vapor/mist phase lubricate a spur gearbox in a preliminary study.

  18. Evaluating Solid-Lubricant Films

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1988-01-01

    Report describes experimental techniques for measuring properties of solid-lubricant films. Discusses experimental parameters. Reviews basic pin-on-disk configurations and methods of preparing disks and applying solid lubricants. Techniques for constant-temperature testing, low-contact-stress testing, and temperature-versus-time testing presented. Suggests methods of measuring pin-wear volume and recommends ways of presenting data.

  19. Boundary lubrication by associative mucin.

    PubMed

    Wang, Xiang; Du, Miao; Han, Hongpeng; Song, Yihu; Zheng, Qiang

    2015-04-28

    Mucus lubricants are widely distributed in living organisms. Such lubricants consist of a gel structure constructed by associative mucin. However, limited tribological studies exist on associative mucin fluids. The present research is the first to investigate the frictional behavior of a typical intact vertebrate mucin (loach skin mucin), which can recover the gel structure of mucus via hydrophobic association under physiological conditions (5-10 mg/mL loach skin mucin dissolved in water). Both rough hydrophobic and hydrophilic polydimethylsiloxane (PDMS) rubber plates were used as friction substrates. Up to 10 mg/mL loach skin mucin dissolved in water led to a 10-fold reduction in boundary friction of the two substrates. The boundary-lubricating ability for hydrophilic PDMS decreased with rubbing time, whereas that for hydrophobic PDMS remained constant. The boundary-lubricating abilities of the mucin on hydrophobic PDMS and hydrophilic PDMS showed almost similar responses toward changing concentration or sodium dodecyl sulfate (SDS). The mucin fluids reduced boundary friction coefficients (μ) only at concentrations (c) in which intermucin associations were formed, with a relationship shown as μ ∼ c(-0.7). Destroying intermucin associations by SDS largely impaired the boundary-lubricating ability. Results reveal for the first time that intermolecular association of intact mucin in bulk solution largely enhances boundary lubrication, whereas tightly adsorbed layer plays a minor role in the lubrication. This study indicates that associated mucin should contribute considerably to the lubricating ability of biological mucus in vivo. PMID:25843576

  20. Elastohydrodynamic lubrication theory

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1982-01-01

    The isothermal elastohydrodynamic lubrication (EHL) of a point contact was analyzed numerically by simultaneously solving the elasticity and Reynolds equations. In the elasticity analysis the contact zone was divided into equal rectangular areas, and it was assumed that a uniform pressure was applied over each area. In the numerical analysis of the Reynolds equation, a phi analysis (where phi is equal to the pressure times the film thickness to the 3/2 power) was used to help the relaxation process. The EHL point contact analysis is applicable for the entire range of elliptical parameters and is valid for any combination of rolling and sliding within the contact.

  1. Development and Implementation of Environmentally Compatible Solid Film Lubricants

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    1998-01-01

    Multi-body launch vehicles require the use of Solid Film Lubricants (SFLS) to allow for unrestricted relative motion between structural assemblies and components during lift-off and ascent into orbit. The Space Shuttle Solid Rocket Booster (SRB), uses a dual coat, ceramic-bonded high temperature SFL in several locations such as restraint hardware between the SRB aft skirt and the Mobile Launch Platform (MLP), the aft SRB/External Tank (ET) attach struts, and the forward skirt SRB/ET attach ball assembly. Future launch systems may require similar applications of SFLs for attachment and restraint hardware. A family of environmentally compatible non-lead/antimony bearing alternative SFLs have been developed including a compatible repair material. In addition, commercial applications for SFLs on transportation equipment, all types of lubricated fasteners, and energy related equipment allow for wide usage's of these new lubricants. The new SFLs trade named BOOSTERLUBE is a family of single layer thin film (0.001 inch maximum) coatings that are a unique mixture of non-hazardous pigments in a compatible resin system that allows for low temperature curing (450F). Significant savings in energy and processing time as well as elimination of hazardous material usage and disposal would result from the non-toxic one-step SFL application. Compatible air-dry field repair lubricants will help eliminate disassembly of launch vehicle restraint hardware during critical time sensitive assembly operations.

  2. Development and Implementation of Environmentally Compatible Solid Film Lubricants

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    1997-01-01

    Multi-body launch vehicles require the use of Solid Film Lubricants (SFLs) to allow for unrestricted relative motion between structural assemblies and components during lift off and ascent into orbit. The Space Shuttle Solid Rocket Booster (SRB), uses a dual coat, ceramic-bonded high temperature SFL in several locations such as restraint hardware between the SRB aft skirt and the Mobile Launch Platform (MLP), the aft SRB/External Tank (ET) attach struts, and the forward skirt SRB/ET attach ball assembly. The proposed National Launch System (NLS) may require similar applications of SFLs for attachment and restraint hardware. A family of environmentally compatible nonlead/antimony bearing alternative SFLs have been developed including a compatible repair material. In addition, commercial applications for SFLs on transportation equipment, all types of lubricated fasteners, and energy related equipment allow for wide usage of these new lubricants. The new SFLs named BOOSTERLUBE is a family of single layer thin film (0.001 inch maximum) coatings that are a unique mixture of non-hazardous pigments in a compatible resin system that allows for low temperature curing (450 F). Significant savings in energy and processing time as well as elimination of hazardous material usage and disposal would result from the non-toxic onestep SFL application. Compatible air-dry field repair lubricants will help eliminate disassembly of launch vehicle restraint hardware during critical time sensitive assembly operations.

  3. Development and Implementation of Environmentally Compatible Solid Film Lubricants

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    1999-01-01

    Multi-body launch vehicles require the use of Solid Film Lubricants (SFLs) to allow for unrestricted relative motion between structural assemblies and components during lift-off and ascent into orbit. The Space Shuttle Solid Rocket Booster (SRB), uses a dual coat, ceramic-bonded high temperature SFL in several locations such as restraint hardware between the SRB aft skirt and the Mobile Launch Platform (MLP), the aft SRB/External Tank (ET) attach struts, and the forward skirt SRB/ET attach ball assembly. Future launch systems may require similar applications of SFLs for attachment and restraint hardware. A family of environmentally compatible non-lead/antimony bearing alternative SFLs have been developed including a compatible repair material. In addition, commercial applications for SFLs on transportation equipment, all types of lubricated fasteners, and energy related equipment allow for wide usage's of these new lubricants. The new SFLs trade named BOOSTERLUBE is a family of single layer thin film (0.001 inch maximum) coatings that are a unique mixture of non-hazardous pigments in a compatible resin system that allows for low temperature curing (450 F). Significant savings in energy and processing time as well as elimination of hazardous material usage and disposal would result from the non-toxic one-step SFL application. Compatible air-dry field repair lubricants will help eliminate disassembly of launch vehicle restraint hardware during critical time sensitive assembly operations.

  4. Vapor phase lubrication of a Ni-based superalloy

    SciTech Connect

    Hanyaloglu, B.; Fedor, D.C.; Graham, E.E.

    1995-03-01

    In addition to ceramics, alloys such as tool steel and nickel- and iron-based superalloys are being considered for high temperature applications such as missile bearings and low heat rejection engines. Studies were made to lubricate a nickel-based superalloy at 500{degrees}C, by using a vaporized aryl phosphate ester, at a concentration of 0.1% in air. From deposition and wear studies it was found that it was impossible to form a good polymeric coating on the superalloy surface. Energy dispersive X-ray analyzer (EDXA) analysis showed that this was due to minute quantities of aluminum in the alloy segregating to the surface, upon being heated to 500{degrees}C, forming a passive oxide coating. It was necessary to activate the surface, in order to lubricate the material successfully. A method of activation by electrodepositing the surface with a layer of iron oxide was developed. Once activated, a good lubricous polymer was formed on the superalloy surface. Tests performed under dynamic conditions and 1 MPa pressure, using an activated specimen surface showed no wear and a coefficient of friction ({mu}) of 0.05. These results stress the importance of material selection for high temperature vapor phase lubrication. 15 refs., 13 figs., 2 tabs.

  5. Characterization of Lubricants on Ball Bearings by FT-IR Using an Integrating Sphere

    NASA Technical Reports Server (NTRS)

    Street, K. W.; Pepper, S. V.; Wright, A. A.; Grady, B.

    2007-01-01

    Fourier Transform-Infrared reflectance microspectroscopy has been used extensively for the examination of coatings on nonplanar surfaces such as ball bearings. While this technique offers considerable advantages, practical application has many drawbacks, some of which are easily overcome by the use of integrating sphere technology. This paper describes the use of an integrating sphere for the quantification of thin layers of lubricant on the surface of ball bearings and the parameters which require optimization in order to obtain reliable data. Several applications of the technique are discussed including determination of lubricant load on 12.7 mm steel ball bearings and the examination of degraded lubricant on post mortem specimens.

  6. Strain-tolerant ceramic coated seal

    DOEpatents

    Schienle, James L.; Strangman, Thomas E.

    1994-01-01

    A metallic regenerator seal is provided having multi-layer coating comprising a NiCrAlY bond layer, a yttria stabilized zirconia (YSZ) intermediate layer, and a ceramic high temperature solid lubricant surface layer comprising zinc oxide, calcium fluoride, and tin oxide. An array of discontinuous grooves is laser machined into the outer surface of the solid lubricant surface layer making the coating strain tolerant.

  7. Succinimide lubricating oil dispersant

    SciTech Connect

    Wisotsky, M.J.; Bloch, R.; Brownwell, D.W.; Chen, F.J.; Gutierrez, A.

    1987-08-11

    A lubricating oil composition is described exhibiting improved dispersancy in both gasoline and diesel engines comprising a major amount of lubricating oil and 0.5 to 10 weight percent of a dispersant, the dispersant being prepared in a sequential process comprising the steps of: (a) in a first step reacting an oil-soluble polyolefin succinic anhydride, the olefin being a C/sub 3/ or C/sub 4/ olefin and an alkylene polyamine of the formula H/sub 2/N(CH/sub 2/)/sub n/(NH(CH/sub 2/)/sub n/)/sub m/sup -// NH/sub 2/ wherein n is 2 or 3 and m is 0 to 10, in a molar ratio of about 1.0 to 2.2 moles of polyolefin succinic anhydride per mole of polyamine, and (b) reacting the product of step (a) with dicarboxylic acid anhydride selected from the group consisting of maleic anhydride and succinic anhydride in sufficient molar proportions to provide a total mole ratio of about 2,3 to 3.0 moles of anhydride compounds per mole of polyamine.

  8. Potentiometer, constant tension and lubrication device

    NASA Technical Reports Server (NTRS)

    Smith, H. J.

    1972-01-01

    Wiper assembly is described for feedback potentiometers which provides self cleaning, self lubrication, and tension within controlled limits. Each end of the assembly contains loose fitting leather pad thoroughly soaked in wiper lubricating fluid. Cleaning and lubrication of potentiometer resulting from use of lubrication soaked leather accomplishes noise free operation.

  9. Interdisciplinary Approach to Liquid Lubricant Technology

    NASA Technical Reports Server (NTRS)

    Ku, P. M. (Editor)

    1973-01-01

    The proceedings of a conference of liquid lubricant technology are presented. The subjects discussed are: (1) requirements and functions of liquid lubricants, (2) mineral oils, (3) greases, (4) theory of rheology, (5) mechanics and thermodynamics in lubrication, (6) environmental capability of liquid lubricants, and (7) wear corrosion and erosion.

  10. Automotive gear oil lubricant from soybean oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of lubricants that are based on renewable materials is rapidly increasing. Vegetable oils have good lubricity, wear protection and low volatility which are desired properties for automotive gear lubricant applications. Soybean oil is used widely in the lubricant industry due to its properti...

  11. Lubrication of space systems: Challenges and potential solutions

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1992-01-01

    Future space missions will all require advanced mechanical moving components which will require wear protection and lubrication. The tribology practices used today are primarily based upon a technology base that is more than 20 years old. This paper will discuss NASA's future space missions and some of the mechanism tribology challenges that will be encountered. Potential solutions to these challenges using coatings technology will be assessed.

  12. Lubricant Rheology in Concentrated Contacts

    NASA Technical Reports Server (NTRS)

    Jacobson, B. O.

    1984-01-01

    Lubricant behavior in highly stressed situtations shows that a Newtonian model for lubricant rheology is insufficient for explanation of traction behavior. The oil film build up is predicted by using a Newtonian lubricant model except at high slide to roll ratios and at very high loads, where the nonNewtonian behavior starts to be important already outside the Hertzian contact area. Static and dynamic experiments are reported. In static experiments the pressure is applied to the lubricant more than a million times longer than in an EHD contact. Depending on the pressure-temperature history of the experiment the lubricant will become a crystallized or amorphous solid at high pressures. In dynamic experiments, the oil is in an amorphous solid state. Depending on the viscosity, time scale, elasticity of the oil and the bearing surfaces, the oil film pressure, shear strain rate and the type of lubricant, different properties of the oil are important for prediction of shear stresses in the oil. The different proposed models for the lubricant, which describe it to a Newtonian liquid, an elastic liquid, a plastic liquid and an elastic-plastic solid.

  13. Lubricant effects on bearing life

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin V.

    1986-01-01

    Lubricant considerations for rolling-element bearings have within the last two decades taken on added importance in the design and operation of mechanical systems. The phenomenon which limits the useful life of bearings is rolling-element or surface pitting fatigue. The elastohydrodynamic (EHD) film thickness which separates the ball or roller surface from those of the raceways of the bearing directly affects bearing life. Chemical additives added to the lubricant can also significantly affect bearings life and reliability. The interaction of these physical and chemical effects is important to the design engineer and user of these systems. Design methods and lubricant selection for rolling-element bearings are presented and discussed.

  14. Investigations of lubricant rheology as applied to elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Carlson, S.; Turchina, V.; Jakobsen, J.; Sanborn, D. M.; Winer, W. O.

    1973-01-01

    The pressure viscometer was modified to permit the measurement of viscosity at elevated pressures and shear stresses up to 5 x 10 to the 6th power N/sq m (720 psi). This shear stress is within a factor of three of the shear stress occurring in a sliding ehd point contact such as occurs in the ehd simulator. Viscosity data were taken on five lubricant samples, and it was found that viscous heating effects on the viscosity were predominant and not non-Newtonian behavior at the high shear stresses. The development of the infrared temperature measuring technique for the ehd simulator was completed, and temperature data for a set of operating conditions and one lubricant are reported. The numerical analysis of the behavior of nonlinear lubricants in the lubrication of rollers is reported.

  15. Environmentally friendly and biobased lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biobased and environmentally friendly lubricants are finding applications in many areas ranging from hydraulic fluids to grease. They offer excellent biodegradability and very low ecotoxicity; high viscosity index; improved tribological properties; lower volatility and flash points relative to petro...

  16. Friction laws for lubricated nanocontacts

    NASA Astrophysics Data System (ADS)

    Buzio, R.; Boragno, C.; Valbusa, U.

    2006-09-01

    We have used friction force microscopy to probe friction laws for nanoasperities sliding on atomically flat substrates under controlled atmosphere and liquid environment, respectively. A power law relates friction force and normal load in dry air, whereas a linear relationship, i.e., Amontons' law, is observed for junctions fully immersed in model lubricants, namely, octamethylciclotetrasiloxane and squalane. Lubricated contacts display a remarkable friction reduction, with liquid and substrate specific friction coefficients. Comparison with molecular dynamics simulations suggests that load-bearing boundary layers at junction entrance cause the appearance of Amontons' law and impart atomic-scale character to the sliding process; continuum friction models are on the contrary of limited predictive power when applied to lubrication effects. An attempt is done to define general working conditions leading to the manifestation of nanoscale lubricity due to adsorbed boundary layers.

  17. Structural lubricity under ambient conditions

    PubMed Central

    Cihan, Ebru; İpek, Semran; Durgun, Engin; Baykara, Mehmet Z.

    2016-01-01

    Despite its fundamental importance, physical mechanisms that govern friction are poorly understood. While a state of ultra-low friction, termed structural lubricity, is expected for any clean, atomically flat interface consisting of two different materials with incommensurate structures, some associated predictions could only be quantitatively confirmed under ultra-high vacuum (UHV) conditions so far. Here, we report structurally lubric sliding under ambient conditions at mesoscopic (∼4,000–130,000 nm2) interfaces formed by gold islands on graphite. Ab initio calculations reveal that the gold–graphite interface is expected to remain largely free from contaminant molecules, leading to structurally lubric sliding. The experiments reported here demonstrate the potential for practical lubrication schemes for micro- and nano-electromechanical systems, which would mainly rely on an atomic-scale structural mismatch between the slider and substrate components, via the utilization of material systems featuring clean, atomically flat interfaces under ambient conditions. PMID:27350035

  18. Self-lubricating composite materials

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1980-01-01

    The mechanical properties of two types of self lubricating composites (polymer matrix composites and inorganic composites) are discussed. Specific emphasis is given to the applicability of these composites in the aerospace industry.

  19. Aviation-fuel lubricity evaluation

    SciTech Connect

    Not Available

    1988-07-01

    Fuel-system components have experienced problems with the slipperiness or lubricity of the fuel back to the early 1960's. As a consequence of the level of refinement necessary for the PWA 523 fuel (now designated MIL-T-38219 grade JP-7) to obtain its high-temperature stability, many of the polar compounds contributing to lubricity had been removed, resulting in abnormal hydraulic fuel-pump wear. A lubricity-enhancing compound was developed (PWA 536) to eliminate the wear problem. High-pressure piston-type fuel pumps were one of the first parts of the engine fuel system to exhibit problems related to fuel properties. One early problem manifested itself as corrosion of silver-plated slipper pads and was related to carryover of residual-chlorides fuel. Fuel controls were another part of the engine fuel system susceptible to fuel properties. Lack of lubricity agents caused fuel control sliding servo valves to stick.

  20. Structural lubricity under ambient conditions

    NASA Astrophysics Data System (ADS)

    Cihan, Ebru; Ipek, Semran; Durgun, Engin; Baykara, Mehmet Z.

    2016-06-01

    Despite its fundamental importance, physical mechanisms that govern friction are poorly understood. While a state of ultra-low friction, termed structural lubricity, is expected for any clean, atomically flat interface consisting of two different materials with incommensurate structures, some associated predictions could only be quantitatively confirmed under ultra-high vacuum (UHV) conditions so far. Here, we report structurally lubric sliding under ambient conditions at mesoscopic (~4,000-130,000 nm2) interfaces formed by gold islands on graphite. Ab initio calculations reveal that the gold-graphite interface is expected to remain largely free from contaminant molecules, leading to structurally lubric sliding. The experiments reported here demonstrate the potential for practical lubrication schemes for micro- and nano-electromechanical systems, which would mainly rely on an atomic-scale structural mismatch between the slider and substrate components, via the utilization of material systems featuring clean, atomically flat interfaces under ambient conditions.

  1. Structural lubricity under ambient conditions.

    PubMed

    Cihan, Ebru; İpek, Semran; Durgun, Engin; Baykara, Mehmet Z

    2016-01-01

    Despite its fundamental importance, physical mechanisms that govern friction are poorly understood. While a state of ultra-low friction, termed structural lubricity, is expected for any clean, atomically flat interface consisting of two different materials with incommensurate structures, some associated predictions could only be quantitatively confirmed under ultra-high vacuum (UHV) conditions so far. Here, we report structurally lubric sliding under ambient conditions at mesoscopic (∼4,000-130,000 nm(2)) interfaces formed by gold islands on graphite. Ab initio calculations reveal that the gold-graphite interface is expected to remain largely free from contaminant molecules, leading to structurally lubric sliding. The experiments reported here demonstrate the potential for practical lubrication schemes for micro- and nano-electromechanical systems, which would mainly rely on an atomic-scale structural mismatch between the slider and substrate components, via the utilization of material systems featuring clean, atomically flat interfaces under ambient conditions. PMID:27350035

  2. Method for lubricating contacting surfaces

    SciTech Connect

    Dugger, Michael T.; Ohlhausen, James A.; Asay, David B.; Kim, Seong H.

    2011-12-06

    A method is provided for tribological lubrication of sliding contact surfaces, where two surfaces are in contact and in motion relative to each other, operating in a vapor-phase environment containing at least one alcohol compound at a concentration sufficiently high to provide one monolayer of coverage on at least one of the surfaces, where the alcohol compound continuously reacts at the surface to provide lubrication.

  3. Frictional anisotropy under boundary lubrication: effect of surface texture.

    SciTech Connect

    Ajayi, O. O.; Erck, R. A.; Lorenzo-Martin, C.; Fenske, G. R.; Energy Systems

    2009-06-15

    The friction coefficient was measured under boundary lubrication with a ball-on-flat contact configuration in unidirectional sliding. The ball was smooth and hardened 52100 steel. Discs were made from case-carburized and hardened 4620, annealed 1080, and 1018 steels with directionally ground surfaces. A synthetic lubricant of stock polyalphaolefin was used for testing. During testing with each material, a frictional spike was observed whenever the ball slid parallel to the grinding ridge on the disc surface. The average friction coefficient for all tests was about 0.1, which is typical for the boundary lubrication regime. The magnitude of the frictional spikes, which reached as high as a friction coefficient of 0.25, and their persistence depended on the hardness of the disc surface. On the basis of elastohydrodynamic theory, coupled with the observation of severe plastic deformation on the ridges parallel to the sliding direction, the frictional spike could be due to localized plastic deformation on the disc surface at locations of minimal thickness for the lubricant fluid film. This hypothesis was further supported by lack of frictional spikes in tests using discs coated with a thin film of diamond-like carbon, in which plastic deformation is minimal.

  4. Combination Thermal Barrier And Wear Coatings For Engines

    NASA Technical Reports Server (NTRS)

    Weingart, Mike; Moller, Paul

    1995-01-01

    Thermal-barrier layers covered with self-lubricating surface layers. Zirconia thermal-barrier coat applied to surface of combustion chamber in engine by plasma-arc spraying. Then PS-200 plasma-arc sprayed onto zirconia. Self-lubricating coat prevents sliding contact between thermal barrier and piston ring, effectively preventing both wear and production of additional heat via friction. Other combinations of thermal-barrier and self-lubricating, wear-resistant coating materials used as long as two materials adhere to each other, applied by use of similar or compatible processes, have similar coefficients of thermal expansion, sufficiently strong at high temperatures, and affordable.

  5. Solid Lubrication Fundamentals and Applications. Chapter 1; Introduction and Background

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1996-01-01

    This chapter presents an introduction and historical background to the field of tribology, especially solid lubrication and lubricants and sets them in the perspective of techniques and materials in lubrication. Also, solid and liquid lubrication films are defined and described.

  6. Solid Lubrication Fundamentals and Applications: Introduction and Background. Revision 1

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1998-01-01

    This chapter presents an introduction and historical background to the field of tribology, especially solid lubrication and lubricants and sets them in the perspective of techniques and materials in lubrication. Also, solid and liquid lubrication films are defined and described.

  7. Tribological Behavior of Aqueous Copolymer Lubricant in Mixed Lubrication Regime.

    PubMed

    Ta, Thi D; Tieu, A Kiet; Zhu, Hongtao; Zhu, Qiang; Kosasih, Prabouno B; Zhang, Jie; Deng, Guanyu

    2016-03-01

    Although a number of experiments have been attempted to investigate the lubrication of aqueous copolymer lubricant, which is applied widely in metalworking operations, a comprehensive theoretical investigation at atomistic level is still lacking. This study addresses the influence of loading pressure and copolymer concentration on the structural properties and tribological performance of aqueous copolymer solution of poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) (PPO-PEO-PPO) at mixed lubrication using a molecular dynamic (MD) simulation. An effective interfacial potential, which has been derived from density functional theory (DFT) calculations, was employed for the interactions between the fluid's molecules and iron surface. The simulation results have indicated that the triblock copolymer is physisorption on iron surface. Under confinement by iron surfaces, the copolymer molecules form lamellar structure in aqueous solution and behave differently from its bulk state. The lubrication performance of aqueous copolymer lubricant increases with concentration, but the friction reduction is insignificant at high loading pressure. Additionally, the plastic deformation of asperity is dependent on both copolymer concentration and loading pressure, and the wear behavior shows a linear dependence of friction force on the number of transferred atoms between contacting asperities. PMID:26828119

  8. Mechanically Tunable Slippery Behavior on Soft Poly(dimethylsiloxane)-Based Anisotropic Wrinkles Infused with Lubricating Fluid.

    PubMed

    Roy, Pritam Kumar; Pant, Reeta; Nagarajan, Arun Kumar; Khare, Krishnacharya

    2016-06-14

    We demonstrate a novel technique to fabricate mechanically tunable slippery surfaces using one-dimensional (anisotropic) elastic wrinkles. Such wrinkles show tunable topography (amplitude) on the application of mechanical strain. Following Nepenthes pitcher plants, lubricating fluid infused solid surfaces show excellent slippery behavior for test liquid drops. Therefore, combining the above two, that is, infusing suitable lubricating fluid on elastic wrinkles, would enable us to fabricate mechanically tunable slippery surfaces. Completely stretched (flat) wrinkles have uniform coating of lubricating fluid, whereas completely relaxed (full amplitude) wrinkles have most of the lubricating oil in the wrinkle grooves. Therefore, water drops on completely stretched surface show excellent slippery behavior, whereas on completely relaxed surface they show reduced slippery behavior. Therefore, continuous variation of wrinkle stretching provides reversibly tunable slippery behavior on such a system. Because the wrinkles are one-dimensional, they show anisotropic tunability of slippery behavior depending upon whether test liquid drops slip parallel or perpendicular to the wrinkles. PMID:27221199

  9. High temperature solid lubricant materials for heavy duty and advanced heat engines

    SciTech Connect

    DellaCorte, C.; Wood, J.C.

    1994-10-01

    Advanced engine designs incorporate higher mechanical and thermal loading to achieve efficiency improvements. This approach often leads to higher operating temperatures of critical sliding elements (e.g. piston ring/cylinder wall contacts and valve guides) which compromise the use of conventional and even advanced synthetic liquid lubricants. For these applications solid lubricants must be considered. Several novel solid lubricant composites and coatings designated PS/PM200 have been employed to dry and marginally oil lubricated contacts in advanced heat engines. These applications include cylinder kits of heavy duty diesels, and high temperature sterling engines, sidewall seals of rotary engines and various exhaust valve and exhaust component applications. The following paper describes the tribological and thermophysical properties of these tribomaterials and reviews the results of applying them to engine applications. Other potential tribological materials and applications are also discussed with particular emphasis to heavy duty and advanced heat engines.

  10. Evaluation of replacement thread lubricants for red lead and graphite in mineral oil

    SciTech Connect

    Jungling, T.L.; Rauth, D.R.; Goldberg, D.

    1998-04-30

    Eight commercially available thread lubricants were evaluated to determine the best replacement for Red Lead and Graphite in Mineral Oil (RLGMO). The evaluation included coefficient of friction testing, high temperature anti-seizing testing, room temperature anti-galling testing, chemical analysis for detrimental impurities, corrosion testing, off-gas testing, and a review of health and environmental factors. The coefficient of friction testing covered a wide variety of factors including stud, nut, and washer materials, sizes, manufacturing methods, surface coatings, surface finishes, applied loads, run-in cycles, and relubrication. Only one lubricant, Dow Corning Molykote P37, met all the criteria established for a replacement lubricant. It has a coefficient of friction range similar to RLGMO. Therefore, it can be substituted directly for RLGMO without changing the currently specified fastener torque values for the sizes, materials and conditions evaluated. Other lubricants did not perform as well as Molykote P37 in one or more test or evaluation categories.

  11. High Temperature Solid Lubricant Materials for Heavy Duty and Advanced Heat Engines

    NASA Technical Reports Server (NTRS)

    Dellacorte, C.; Wood, J. C.

    1994-01-01

    Advanced engine designs incorporate higher mechanical and thermal loading to achieve efficiency improvements. This approach often leads to higher operating temperatures of critical sliding elements (e.g. piston ring/cylinder wall contacts and valve guides) which compromise the use of conventional and even advanced synthetic liquid lubricants. For these applications solid lubricants must be considered. Several novel solid lubricant composites and coatings designated PS/PM200 have been employed to dry and marginally oil lubricated contacts in advanced heat engines. These applications include cylinder kits of heavy duty diesels, and high temperature Stirling engines, sidewall seals of rotary engines, and various exhaust valve and exhaust component applications. This paper describes the tribological and thermophysical properties of these tribomaterials and reviews the results of applying them to engine applications. Other potential tribological materials and applications are also discussed with particular emphasis on heavy duty and advanced heat engines.

  12. Engine lubrication circuit including two pumps

    DOEpatents

    Lane, William H.

    2006-10-03

    A lubrication pump coupled to the engine is sized such that the it can supply the engine with a predetermined flow volume as soon as the engine reaches a peak torque engine speed. In engines that operate predominately at speeds above the peak torque engine speed, the lubrication pump is often producing lubrication fluid in excess of the predetermined flow volume that is bypassed back to a lubrication fluid source. This arguably results in wasted power. In order to more efficiently lubricate an engine, a lubrication circuit includes a lubrication pump and a variable delivery pump. The lubrication pump is operably coupled to the engine, and the variable delivery pump is in communication with a pump output controller that is operable to vary a lubrication fluid output from the variable delivery pump as a function of at least one of engine speed and lubrication flow volume or system pressure. Thus, the lubrication pump can be sized to produce the predetermined flow volume at a speed range at which the engine predominately operates while the variable delivery pump can supplement lubrication fluid delivery from the lubrication pump at engine speeds below the predominant engine speed range.

  13. Silica Lubrication in Faults (Invited)

    NASA Astrophysics Data System (ADS)

    Rowe, C. D.; Rempe, M.; Lamothe, K.; Kirkpatrick, J. D.; White, J. C.; Mitchell, T. M.; Andrews, M.; Di Toro, G.

    2013-12-01

    Silica-rich rocks are common in the crust, so silica lubrication may be important for causing fault weakening during earthquakes if the phenomenon occurs in nature. In laboratory friction experiments on chert, dramatic shear weakening has been attributed to amorphization and attraction of water from atmospheric humidity to form a 'silica gel'. Few observations of the slip surfaces have been reported, and the details of weakening mechanism(s) remain enigmatic. Therefore, no criteria exist on which to make comparisons of experimental materials to natural faults. We performed a series of friction experiments, characterized the materials formed on the sliding surface, and compared these to a geological fault in the same rock type. Experiments were performed in the presence of room humidity at 2.5 MPa normal stress with 3 and 30 m total displacement for a variety of slip rates (10-4 - 10-1 m/s). The friction coefficient (μ) reduced from >0.6 to ~0.2 at 10-1 m/s, but only fell to ~0.4 at 10-2 - 10-4 m/s. The slip surfaces and wear material were observed using laser confocal Raman microscopy, electron microprobe, X-ray diffraction, and transmission electron microscopy. Experiments at 10-1 m/s formed wear material consisting of ≤1 μm powder that is aggregated into irregular 5-20 μm clumps. Some material disaggregated during analysis with electron beams and lasers, suggesting hydrous and unstable components. Compressed powder forms smooth pavements on the surface in which grains are not visible (if present, they are <100 nm). Powder contains amorphous material and as yet unidentified crystalline and non-crystalline forms of silica (not quartz), while the worn chert surface underneath shows Raman spectra consistent with a mixture of quartz and amorphous material. If silica amorphization facilitates shear weakening in natural faults, similar wear materials should be formed, and we may be able to identify them through microstructural studies. However, the sub

  14. The experimental evaluation and application of high-temperature solid lubricants. Ph.D. Thesis - Case Western Reserve Univ., 1989 Final Report

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher

    1990-01-01

    A research program is described which developes an understanding of high-temperature solid lubrication and experimental techniques through the development of a composite lubricant coating system. The knowledge gained through this research was then applied to a specific engineering challenge, the tribology of a sliding seal for hypersonic flight vehicles. The solid lubricant coating is a chromium carbide based composite combined with silver, which acts as a low temperature lubricant, and barium fluoride/calcium fluoride eutectic, which acts as a high-temperature lubricant. This composite coating provides good wear resistance and low friction for sliding contacts from room temperature to over 900 C in reducing or oxidative environments. The specific research on this coating included a composition screening using a foil gas bearing test rig and the use of thin silver films to reduce initial wear using a pin-on-disk test rig. The chemical stability of the materials used was also addressed. This research indicated that soft metallic films and materials which become soft at elevated temperatures are potentially good lubricants. The general results from the experiments with the model solid lubricant coating were then applied to a sliding seal design concept. This seal design requires that a braided ceramic fabric slide against a variety of metal counterface materials at temperatures from 25 to 850 C in an oxidative environment. A pin-on-disk tribometer was used to evaluate the tribological properties of these materials and to develop lubrication techniques. The results indicate that these seal materials must be lubricated to prevent wear and reduce friction. Thin films of silver, gold and calcium fluoride provided lubrication to the sliding materials.

  15. Ionic Liquids as Novel Lubricants and /or Lubricant Additives

    SciTech Connect

    Qu, J.; Viola, M. B.

    2013-10-31

    This ORNL-GM CRADA developed ionic liquids (ILs) as novel lubricants or oil additives for engine lubrication. A new group of oil-miscible ILs have been designed and synthesized with high thermal stability, non-corrosiveness, excellent wettability, and most importantly effective anti-scuffing/anti-wear and friction reduction characteristics. Mechanistic analysis attributes the superior lubricating performance of IL additives to their physical and chemical interactions with metallic surfaces. Working with a leading lubricant formulation company, the team has successfully developed a prototype low-viscosity engine oil using a phosphonium-phosphate IL as an anti-wear additive. Tribological bench tests of the IL-additized formulated oil showed 20-33% lower friction in mixed and elastohydrodynamic lubrication and 38-92% lower wear in boundary lubrication when compared with commercial Mobil 1 and Mobil Clean 5W-30 engine oils. High-temperature, high load (HTHL) full-size engine tests confirmed the excellent anti-wear performance for the IL-additized engine oil. Sequence VID engine dynamometer tests demonstrated an improved fuel economy by >2% for this IL-additized engine oil benchmarked against the Mobil 1 5W-30 oil. In addition, accelerated catalyst aging tests suggest that the IL additive may potentially have less adverse impact on three-way catalysts compared to the conventional ZDDP. Follow-on research is needed for further development and optimization of IL chemistry and oil formulation to fully meet ILSAC GF-5 specifications and further enhance the automotive engine efficiency and durability.

  16. Top-of-Rail lubricant

    SciTech Connect

    Alzoubi, M. F.; Fenske, G. R.; Erck, R. A.; Boparai, A. S.

    2000-07-14

    Analysis of the volatile and semivolatile fractions collected after use of the TOR lubricant indicated that other than contaminants in the collection laboratory, no compounds on the EPA's Target Compound Lists (Tables 2 and 5) were detected in these fractions. The data of these qualitative analyses, given in the various tables in the text, indicate only the relative amounts of the tentatively identified compounds. The authors recommend that quantitative analysis be performed on the volatile and semivolatile fractions to allow confirmation of the tentatively identified compounds and to obtain absolute amounts of the detected compounds. Additionally, the semivolatile fraction should be analyzed by liquid chromatography/mass spectrometry to identify compounds that are not chromatographable under the temperature program used for determination of semivolatile compounds. Introducing the top-of-rail (TOR) lubricant into the wheel/rail interface results in a reduction of almost 60% of lateral friction force over the forces encountered under dry conditions. This reveals good potential for energy savings, as well as wear reduction, for railroad companies. In TOR lubrication, an increase in the angle of attack and axle load results in increased lateral friction and rate of lubricant consumption. The most efficient TOR lubricant quantity to be used in the wheel/rail interface must be calculated precisely according to the number of cars, axle loads, train speed, and angle of attack.

  17. Investigations of lubricant rheology as applied to elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Bair, S.; Winer, W. O.

    1978-01-01

    Measurements of lubricant shear rheological behavior in the amorphous solid region and near the liquid-solid transition are reported. Elastic, plastic and viscous behavior was observed. A shear rheological model based on primary laboratory data is proposed for concentrated contact lubrication. The model is a Maxwell model modified with a limiting shear stress. Three material properties are required: low shear stress viscosity, limiting elastic shear modulus, and the limiting shear stress the material can withstand. All three are functions of temperature and pressure. In applying the model to EHD contacts the predicted response possesses the characteristics expected from several experiments reported in the literature.

  18. Lubricant composition of improved friction reducing properties

    SciTech Connect

    Malec, R.E.

    1980-05-06

    Lubricating oil is disclosed for use as a crankcase lubricant in internal combustion engines containing a friction-reducing amount of a sulfurized fatty acid amide, ester or ester-amide of an oxyalkylated amine.

  19. Metalworking corrosion inhibition/drawing lubricant

    SciTech Connect

    Lipinski, H.F.; Wantling, S.J.

    1980-05-06

    A metalworking lubricant composition is disclosed which is effective as both a corrosion inhibitor and drawing lubricant and comprises a mineral oil and an additive combination of barium lanolate soap and barium sulfonate.

  20. Preliminary Results of Cleaning Process for Lubricant Contamination

    SciTech Connect

    Eisenmann, D.; Brasche, L.; Lopez, R.

    2006-03-06

    Fluorescent penetrant inspection (FPI) is widely used for aviation and other components for surface-breaking crack detection. As with all inspection methods, adherence to the process parameters is critical to the successful detection of defects. Prior to FPI, components are cleaned using a variety of cleaning methods which are selected based on the alloy and the soil types which must be removed. It is also important that the cleaning process not adversely affect the FPI process. There are a variety of lubricants and surface coatings used in the aviation industry which must be removed prior to FPI. To assess the effectiveness of typical cleaning processes on removal of these contaminants, a study was initiated at an airline overhaul facility. Initial results of the cleaning study for lubricant contamination in nickel, titanium and aluminum alloys will be presented.

  1. Engineering Lubrication in Articular Cartilage

    PubMed Central

    McNary, Sean M.; Athanasiou, Kyriacos A.

    2012-01-01

    Despite continuous progress toward tissue engineering of functional articular cartilage, significant challenges still remain. Advances in morphogens, stem cells, and scaffolds have resulted in enhancement of the bulk mechanical properties of engineered constructs, but little attention has been paid to the surface mechanical properties. In the near future, engineered tissues will be able to withstand and support the physiological compressive and tensile forces in weight-bearing synovial joints such as the knee. However, there is an increasing realization that these tissue-engineered cartilage constructs will fail without the optimal frictional and wear properties present in native articular cartilage. These characteristics are critical to smooth, pain-free joint articulation and a long-lasting, durable cartilage surface. To achieve optimal tribological properties, engineered cartilage therapies will need to incorporate approaches and methods for functional lubrication. Steady progress in cartilage lubrication in native tissues has pushed the pendulum and warranted a shift in the articular cartilage tissue-engineering paradigm. Engineered tissues should be designed and developed to possess both tribological and mechanical properties mirroring natural cartilage. In this article, an overview of the biology and engineering of articular cartilage structure and cartilage lubrication will be presented. Salient progress in lubrication treatments such as tribosupplementation, pharmacological, and cell-based therapies will be covered. Finally, frictional assays such as the pin-on-disk tribometer will be addressed. Knowledge related to the elements of cartilage lubrication has progressed and, thus, an opportune moment is provided to leverage these advances at a critical step in the development of mechanically and tribologically robust, biomimetic tissue-engineered cartilage. This article is intended to serve as the first stepping stone toward future studies in functional

  2. Engineering lubrication in articular cartilage.

    PubMed

    McNary, Sean M; Athanasiou, Kyriacos A; Reddi, A Hari

    2012-04-01

    Despite continuous progress toward tissue engineering of functional articular cartilage, significant challenges still remain. Advances in morphogens, stem cells, and scaffolds have resulted in enhancement of the bulk mechanical properties of engineered constructs, but little attention has been paid to the surface mechanical properties. In the near future, engineered tissues will be able to withstand and support the physiological compressive and tensile forces in weight-bearing synovial joints such as the knee. However, there is an increasing realization that these tissue-engineered cartilage constructs will fail without the optimal frictional and wear properties present in native articular cartilage. These characteristics are critical to smooth, pain-free joint articulation and a long-lasting, durable cartilage surface. To achieve optimal tribological properties, engineered cartilage therapies will need to incorporate approaches and methods for functional lubrication. Steady progress in cartilage lubrication in native tissues has pushed the pendulum and warranted a shift in the articular cartilage tissue-engineering paradigm. Engineered tissues should be designed and developed to possess both tribological and mechanical properties mirroring natural cartilage. In this article, an overview of the biology and engineering of articular cartilage structure and cartilage lubrication will be presented. Salient progress in lubrication treatments such as tribosupplementation, pharmacological, and cell-based therapies will be covered. Finally, frictional assays such as the pin-on-disk tribometer will be addressed. Knowledge related to the elements of cartilage lubrication has progressed and, thus, an opportune moment is provided to leverage these advances at a critical step in the development of mechanically and tribologically robust, biomimetic tissue-engineered cartilage. This article is intended to serve as the first stepping stone toward future studies in functional

  3. Lubrication of rolling-element bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.

    1980-01-01

    The lubrication of rolling element bearings is surveyed. Emphasis is on the critical design aspects related to speed, temperature, and ambient pressure environment. Types of lubrication including grease, jets, mist, wick, and through the race are discussed. The historical development, present state of technology, and the future problems of rolling element bearing lubrication are discussed.

  4. Research on Liquid Lubricants for Space Mechanisms

    NASA Technical Reports Server (NTRS)

    Jones, William R., Jr.; Shogrin, Bradley A.; Jansen, Mark J.

    1999-01-01

    Four research areas at the NASA Glenn Research Center involving the tribology of space mechanisms are highlighted. These areas include: soluble boundary lubrication additives for perfluoropolyether liquid lubricants, a Pennzane dewetting phenomenon, the effect of ODC-free bearing cleaning processes on bearing lifetimes and the development of a new class of liquid lubricants based on silahydrocarbons.

  5. Properties of dry film lubricants prepared by spray application of aqueous starch-oil composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aqueous dispersions of starch-soybean oil (SBO) and starch-jojoba oil (JO) composites, prepared by excess steam jet cooking, form effective dry film lubricants when applied as thick coatings to metal surfaces by doctor blade. This application method necessitates long drying times, is wasteful, requ...

  6. Coatings for high-temperature bearings and seals

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1987-01-01

    Criteria are discussed for predicting the probable lubricating ability of candidate solid materials from a consideration of their basic chemical and physical properties. The properties considered to be important in the model are thermochemical potential, adhesion, low hardness, plasticity, yield strength in shear, and brittle-to-ductile transition characteristics. A review of the selection and tribological testing of materials, which were selected for use in self-lubricating composite coatings by employing this model, is given. Two series of plasma-sprayed coatings with good tribological properties over a wide temperature spectrum are described. The PS 100 series of coatings contain oxidatively stable solid lubricants in a nichrome matrix. The PS 200 series contains the same solid lubricants in a very wear resistant metal-bonded chromium carbide matrix. Examples are given of applications of these coatings in high speed shaft seals, sliding contact bearings, and Stirling engine cylinder liners.

  7. Materials: A compilation. [considering metallurgy, polymers, insulation, and coatings

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Technical information is provided for the properties and fabrication of metals and alloys, as well as for polymeric materials, such as lubricants, coatings, and insulation. Available patent information is included in the compilation.

  8. Synthesis of new high performance lubricants and solid lubricants

    SciTech Connect

    Lagow, Richard J.

    1993-04-08

    In our second year of funding we began the testing phase of a number of new classes of lubricants. Three different testing collaborations have already begun and a fourth one is In the works with Dr. Stephen Hsu of the National Institute of Standards and Technology. Dr. Hsu also plans to test some of the same materials for us that Shell Development is studying. With Dr. Bill Jones of NASA, we are studying the effects of branching an high temperature lubricant properties in perfluoropolyethers, Initially Bill Jones is comparing the lubrication and physical properties of perfluorotetraglyme and the following two spherical perfluoropolyethers, Note that one contains a fluorocarbon chain and the other one contains a fluorocarbon ether chain. The synthesis of these was reported in the last progress report. With Professor Patricia Thiel of Iowa State University, we are working on studies of perfluoromethylene oxide ethers and have prepared a series of four of these polyethers to study in collaboration with her research group. These perfluoromethylene oxide ethers have the best low temperature properties of any known lubricants. Thiel's group is studying their interactions with metals under extreme conditions. Thirdly, we have also begun an Interaction with W. August Birke of Shell Development Company in Houston for whom we have already prepared samples of the chlorine-substituted fluorocarbon polyether lubricants whose structures appear on page 54 of our research proposal. Each of these four structures is thought to have potential as lubricant additives to motor oils. We also have underway syntheses of other fluorine-containing branched ether lubricants. These new materials which are also promising as antifriction additives for motor oils appear ahead of the perfluoro additives as Appendix I to the progress report. Additionally for Birke and Shell Development we have at their request prepared the novel compound perfluoro salicylic acid. This synthesis was suggested by the

  9. Compilation of diamond-like carbon properties for barriers and hard coatings

    SciTech Connect

    Outka, D.A.; Hsu, Wen L.; Boehme, D.R.; Yang, N.Y.C.; Ottesen, D.K.; Johnsen, H.A.; Clift, W.M.; Headley, T.J.

    1994-02-01

    Diamond-like carbon (DLC) is an amorphous form of carbon which resembles diamond in its hardness, lubricity, and interest for hardness, lubricity, and resistance to chemical attack. Such properties make DLC of use in barrier and hard coating technology. This report examines a variety of properties of DLC coatings which are relevant to its use as a protective coating. This includes examining substrates on which DLC coatings can be deposited; the resistance of DLC coatings to various chemical agents; adhesion of DLC coatings; and characterization of DLC coatings by electron microscopy, FTIR, sputter depth profiling, stress measurements, and nanoindentation.

  10. Experimental Analysis of Damping and Tribological Characteristics of Nano-CuO Particle Mixed Lubricant in Ball Bearings

    NASA Astrophysics Data System (ADS)

    Prakash, E.; Sivakumar, K.

    2015-12-01

    Experimental analysis of damping capacity and tribological characteristics of nano CuO added Servosystem 68 lubricant is attempted. CuO nano particles were synthesized by aqueous precipitation method and characterized. Prior to dispersion into lubricant, CuO nano particles were coated with 0.2 wt.% surfactant (Span-80) to stabilize the nano fluid. Tribological characteristics of particle added lubricant were tested in ASTM D 4172 four ball wear tester. Scanning electron microscopy test results of worn surfaces of nano CuO particle added lubricant were smoother than base lubricant. The particle added lubricant was applied in a new ball bearing and three defected ball bearings. When particle added lubricant was used, the ball defected bearing's vibration amplitude was reduced by 21.94% whereas it was 16.46% for new bearing and was ≤ 11% for other defected bearings. The formation of protection film of CuO over ball surface and regime of full film lubrication near the ball zone were observed to be reason for improved damping of vibrations.

  11. High-Temperature Solid Lubricants Developed by NASA Lewis Offer Virtually "Unlimited Life" for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Valco, Mark J.

    1999-01-01

    The NASA Lewis Research Center is capitalizing on breakthroughs in foil air bearing performance, tribological coatings, and computer analyses to formulate the Oil-free Turbomachinery Program. The program s long-term goal is to develop an innovative, yet practical, oil-free aeropropulsion gas turbine engine that floats on advanced air bearings. This type of engine would operate at higher speeds and temperatures with lower weight and friction than conventional oil-lubricated engines. During startup and shutdown, solid lubricant coatings are required to prevent wear in such engines before the self-generating air-lubrication film develops. NASA s Tribology Branch has created PS304, a chrome-oxide-based plasma spray coating specifically tailored for shafts run against foil bearings. PS304 contains silver and barium fluoride/calcium fluoride eutectic (BaF2/CaF2) lubricant additives that, together, provide lubrication from cold start temperatures to over 650 C, the maximum use temperature for foil bearings. Recent lab tests show that bearings lubricated with PS304 survive over 100 000 start-stop cycles without experiencing any degradation in performance due to wear. The accompanying photograph shows a test bearing after it was run at 650 C. The rubbing process created a "polished" surface that enhances bearing load capacity.

  12. Self lubrication of bitumen froth in pipelines

    SciTech Connect

    Joseph, D.D.

    1997-12-31

    In this paper I will review the main properties of water lubricated pipelines and explain some new features which have emerged from studies of self-lubrication of Syncrudes` bitumen froth. When heavy oils are lubricated with water, the water and oil are continuously injected into a pipeline and the water is stable when in a lubricating sheath around the oil core. In the case of bitumen froth obtained from the Alberta tar sands, the water is dispersed in the bitumen and it is liberated at the wall under shear; water injection is not necessary because the froth is self-lubricating.

  13. Tetrasulfide extreme pressure lubricant additives

    SciTech Connect

    Gast, L.E.; Kenney, H.E.; Schwab, A.W.

    1980-08-19

    A novel class of compounds has been prepared comprising the tetrasulfides of /sup 18/C hydrocarbons, /sup 18/C fatty acids, and /sup 18/C fatty and alkyl and triglyceride esters. These tetrasulfides are useful as extreme pressure lubricant additives and show potential as replacements for sulfurized sperm whale oil.

  14. Lubricant Selection Manual, Phase 3

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Lowry, J. A.; Dufrane, K. F.

    1991-01-01

    Future spacecraft must be designated to operate for very long time periods in space. For example, a target goal for the Space Station is 30 years of operation. Although the actual life may be significantly less than this optimistic goal, the life will certainly be a critical issue in design. The bearings on primary components such as the alpha and beta joints must obviously be designed and lubricated with the objective of optimum performance life. In addition to these joints, there will be numerous other tribological (rubbing or rolling) interfaced that will be required to function for the life of the spacecraft. A major key to adequate performance of tribological interface is proper lubrication. Lubricants can be divided into two basic classes: solid films and liquids. Both types have been used extensively in space applications. Both have advantages and disadvantages that must be carefully considered in their selection. The purpose here is to summarize selection criteria for liquid and solid lubricants applied to long-life spacecraft.

  15. Longevity Of Dry Film Lubricants

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Stockwell, R. D.

    1993-01-01

    Report describes evaluation of dry film lubricants candidate for use in rotary joints of proposed Space Station. Study included experiments and theoretical analyses focused on longevity of sputtered molybdenum disulfide films and ion-plated lead films under conditions partially simulating rolling contact.

  16. Tribology and coatings

    SciTech Connect

    1995-06-01

    The future use of fuel-efficient, low-emission, advanced transportation systems (for example, those using low-heat-rejection diesel engines or advanced gas turbines) presents new challenges to tribologists and materials scientists. High service temperatures, corrosive environments, and extreme contact pressures are among the concerns that make necessary new tribological designs, novel materials, and effective lubrication concepts. Argonne is working on methods to reduce friction, wear and corrosion, such as soft metal coatings on ceramics, layered compounds, diamond coatings, and hard surfaces.

  17. Lubricants and Additives Affect Spur-Gear Fatigue

    NASA Technical Reports Server (NTRS)

    Scibbe, H.; Townsend, D.; Aron, P.; Zaretsky, E.

    1986-01-01

    Surface-fatigue tests conducted with AISI 9310 steel spur gears show surface-fatigue life of AISI 9310 steel spur gears increased as much as 400 percent by addition of small amount of phosphorus-type extreme-pressure (EP) additive in lubricant. Antiwear or EP additives either absorbed onto surface or react with surface to form protective coating or surface film. Boundary film provides barrier that prevents contact of metal surfaces and provides low shear strength, which reduces friction coefficient below base metal.

  18. Applying robotic technology to the solid film lubricant burnishing operation

    SciTech Connect

    Fureigh, M.L.

    1984-02-01

    The PUMA 260, a programmable robot, has been used to burnish up to 22 different parts coated with solid film lubricant in the Painting Department. Some other parts also are potential candidates for robotic applications. Robot technology can reduce the burnishing operation standard hours and relieve workers' fatigue and strain as well as produce more uniform part-to-part quality. Using VAL, the versatile computer program language for PUMA 260, the process engineer can define the optimum robot burnishing actions and speeds for each part.

  19. Lubricant evaluation of the alpha and beta joints, phase 2

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Stockwell, R. D.

    1992-01-01

    A research study was conducted to evaluate dry film lubrication of long life space components such as the alpha and beta joints of the Space Station. The problem addressed in the report pertains to the longevity of sputtered MoS2 or ion plated lead films in a rolling contact environment. A special technique was devised for the experiments, which incorporated a coated ball cyclically loaded against a flat plate. At fixed intervals the surface of the coating was photographed at 100X magnification. By computer scanning the photographs, the rate of coating loss was determined. Experimental variables include load and surface finish of the plate. A theory was developed to analyze the state of stress between ball and flat. The stress condition in the ball apparatus was related to the state of stress under rolling contact conditions. Based on the experiments life appeared to decrease with increasing load and increasing surface roughness. An ion plated lead film gave better life than a sputtered MoS2 film. However, by keeping the interfacial shear stress at a low level, adequate coating life was achieved for either coating. For the lead film, the critical stress was about 0.19 GPa (28 ksi). The study dealt only with mechanical wear. Before a coating is selected for a critical space application, other factors such as reaction with atomic oxygen must also be considered.

  20. Investigations of lubricant rheology as applied to elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Kunz, R. K.; Nagaraj, H. S.; Sanborn, D. M.; Winer, W. O.

    1975-01-01

    Traction prediction in sliding elastohydrodynamic (EHD) contacts was examined along with an elastohydrodynamic lubrication simulation of the effects of load and speed on temperatures in the EHD contact. An existing shear stress theory and lubricant rheological model were studied and evaluated by applying them to traction prediction. Results obtained using measured film thickness and surface temperature data, were compared with measured traction values. The infrared technique for measuring temperatures in an EHD contact was further developed and ball surface and fluid temperatures are reported for sliding speeds of 0.35 to 5.08 m/s at 0.52 to 2.03 GN/sq m maximum pressure and surface roughnesses of .011 to .381 micrometers c.1.a. The relationship between asperity interaction, as measured by relocation surface profilimetry and high frequency temperature measurements, and the ratio of film thickness to surface roughness was also studied.

  1. Lubricant Supply from Crystal Boundaries of Perpendicular Magnetic Disk Evaluated by Lateral Modulation Friction Force Microscopy

    NASA Astrophysics Data System (ADS)

    Miyake, Shojiro; Takahashi, Yuuzi; Wang, Mei; Saitoh, Tadashi; Matsunuma, Satoshi

    2004-11-01

    The tribological behavior of perfluoropolyether (PFPE) films attached to perpendicular recording magnetic disks coated with diamondlike carbon (DLC) was studied in lateral vibration wear tests using lateral modulus friction force microscopy (LM-FFM). The viscoelastic and frictional properties of these PFPE films without heat cure were improved due to the lubricant supply by tip sliding. However, the PFPE films were easily removed with increasing load and lateral vibration amplitude following heat treatment since the free lubricants on the films solidified resulting in the lost of fluidity.

  2. Performance of two MOV lubricants

    SciTech Connect

    Gleeson, J.B.; Cline, T.

    1996-12-01

    Recent testing at Battelle has shown that a synthetic grease (Mobil 28) provides both improved friction coefficient and lower rate-of-loading (ROL) characteristics. Duke Power nuclear plants currently use an antiseize (N5000) as a motor operated valve (MOV) stem lubricant but they are considering changing to Mobil 28. However, it is not practical to completely remove all the residual antiseize from the steam threads when changing to a new lubricant. The testing performed during this study was to determine the friction coefficient and ROL effects for Mobil 28 when applied to a valve stem with residual N5000. This testing demonstrated how mixtures of Mobil 28 and N5000 perform under varying MOV conditions.

  3. Biofluid lubrication for artificial joints

    NASA Astrophysics Data System (ADS)

    Pendleton, Alice Mae

    This research investigated biofluid lubrication related to artificial joints using tribological and rheological approaches. Biofluids studied here represent two categories of fluids, base fluids and nanostructured biofluids. Base fluids were studied through comparison of synthetic fluids (simulated body fluid and hyaluronic acid) as well as natural biofluids (from dogs, horses, and humans) in terms of viscosity and fluid shear stress. The nano-structured biofluids were formed using molecules having well-defined shapes. Understanding nano-structured biofluids leads to new ways of design and synthesis of biofluids that are beneficial for artificial joint performance. Experimental approaches were utilized in the present research. This includes basic analysis of biofluids' property, such as viscosity, fluid shear stress, and shear rate using rheological experiments. Tribological investigation and surface characterization were conducted in order to understand effects of molecular and nanostructures on fluid lubrication. Workpiece surface structure and wear mechanisms were investigated using a scanning electron microscope and a transmission electron microscope. The surface topography was examined using a profilometer. The results demonstrated that with the adding of solid additives, such as crown ether or fullerene acted as rough as the other solids in the 3-body wear systems. In addition, the fullerene supplied low friction and low wear, which designates the lubrication purpose of this particular particle system. This dissertation is constructed of six chapters. The first chapter is an introduction to body fluids, as mentioned earlier. After Chapter II, it examines the motivation and approach of the present research, Chapter III discusses the experimental approaches, including materials, experimental setup, and conditions. In Chapter IV, lubrication properties of various fluids are discussed. The tribological properties and performance nanostructured biofluids are

  4. Powder-lubricated piston ring development

    NASA Astrophysics Data System (ADS)

    Heshmat, H.

    1991-06-01

    The overall objective of this program was to demonstrate the feasibility of a new particulate lubrication concept for reducing piston ring/cylinder liner wear in coal-water slurry-fueled diesels by replacing the present oil-lubricated system with powder lubrication that would utilize coal ash, either alone or in combination with another powder. The feasibility of this particular lubrication concept for reducing ring/liner wear was demonstrated in a series of experiments utilizing redesigned and properly selected components. Wear performance for suitable ring/liner materials lubricated with a powder that incorporates the abrasive ash particles was evaluated in terms of load capacity, friction, and rate of wear for the best combination of ring design, ring and liner materials, and powder constituents. In addition, the use of a powder-lubricated system in the upper portion of the cylinder isolated the particulates from the lower portions of the engine, thus further reducing engine wear.

  5. Powder-lubricated piston ring development

    SciTech Connect

    Heshmat, H.

    1991-06-01

    The overall objective of this program was to demonstrate the feasibility of a new particulate lubrication concept for reducing piston ring/cylinder liner wear in coal-water slurry-fueled diesels by replacing the present oil-lubricated system with powder lubrication that would utilize coal ash, either alone or in combination with another powder. The feasibility of this particular lubrication concept for reducing ring/liner wear was demonstrated in a series of experiments utilizing redesigned and properly selected components. Wear performance for suitable ring/liner materials lubricated with a powder that incorporates the abrasive ash particles was evaluated in terms of load capacity, friction, and rate of wear for the best combination of ring design, ring and liner materials, and powder constituents. In addition, the use of a powder-lubricated system in the upper portion of the cylinder isolated the particulates from the lower portions of the engine, thus further reducing engine wear. (VC)

  6. Elastohydrodynamic lubrication of elliptical contacts

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1982-01-01

    Fully flooded, elastohydrodynamically lubricated, elliptical contacts are discussed. The relevant equations used in the elastohydrodynamic lubrication (EHL) of elliptical contacts are briefly described. Film thickness equations are developed for materials of high elastic modulus, such as metal, and for materials of low elastic modulus, such as rubber. In addition to the film thickness equations that are developed, plots of pressure and film thickness are presented. A theoretical study of the influence of lubricant starvation on film thickness and pressure in hard and soft elliptical elastohydrodynamic contacts is presented. From the results for both hard and soft EHL contacts a simple and important dimensionless inlet boundary distance is specified. It is also found that the film thickness for a starved condition can be written in dimensionless terms as a function of the inlet distance parameter and the film thickness for a fully flooded condition. contour plots of pressure and film thickness in and around the contact are shown for fully flooded and starved conditions. The theoretical findings are compared directly with results obtained experimentally.

  7. Elastohydrodynamic lubrication of elliptical contacts

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1981-01-01

    The determination of the minimum film thickness within contact is considered for both fully flooded and starved conditions. A fully flooded conjunction is one in which the film thickness is not significantly changed when the amount of lubricant is increased. The fully flooded results presented show the influence of contact geometry on minimum film thickness as expressed by the ellipticity parameter and the dimensionless speed, load, and materials parameters. These results are applied to materials of high elastic modulus (hard EHL), such as metal, and to materials of low elastic modulus(soft EHL), such as rubber. In addition to the film thickness equations that are developed, contour plots of pressure and film thickness are given which show the essential features of elastohydrodynamically lubricated conjunctions. The crescent shaped region of minimum film thickness, with its side lobes in which the separation between the solids is a minimum, clearly emerges in the numerical solutions. In addition to the 3 presented for the fully flooded results, 15 more cases are used for hard EHL contacts and 18 cases are used for soft EHL contacts in a theoretical study of the influence of lubricant starvation on film thickness and pressure. From the starved results for both hard and soft EHL contacts, a simple and important dimensionless inlet boundary distance is specified. This inlet boundary distance defines whether a fully flooded or a starved condition exists in the contact. Contour plots of pressure and film thickness in and around the contact are shown for conditions.

  8. Optimum Me-DLC coatings and hard coatings for tribological performance[Diamond-Like Carbon

    SciTech Connect

    Su, Y.L.; Kao, W.H.

    2000-02-01

    In this study, hard coatings (TiN, TiCN, CrN, and CrCN) and Me-DLC coatings (Ti{sub x%}-C:H and Cr{sub x%}-C:H) were deposited on tungsten carbide (WC) substrate by multiarc physical vapor deposition (MAPVD) and unbalanced magnetron (UBM) sputtering, respectively. Counterbodies of the AISI 1045 steel cylinder and the AA7075T65l aluminum cylinder were used in the cylinder-on-disk, line-contact wear mode under dry condition; a counterbody of the AISI 51200 steel ball was used in the ball-on-disk, point-contact wear mode, under both dry and lubricated conditions. All wear tests were conducted with a reciprocating machine. After the tests, the most suitable coating for various counterbodies and test environments was selected. For the coating/1045 steel cylinder, the Ti{sub 10%}-C:H coating possesses excellent tribological characteristics. For the coating/7075T651 aluminum cylinder, hard coatings display excellent wear resistance. For the coating/steel ball, CrCN and CrN coatings display very little wear under both dry and lubricated conditions. On TiN and TiCN coatings, special wear mechanisms of material transfer, adhesion wear, and fatigue fracture occurred during initial tests under kerosene lubrication.

  9. Lubricating oil compositions containing organometallic additives

    SciTech Connect

    Landry, J.F.; Croudance, M.C.; On, H.P.; Shen, S.Y.

    1987-04-07

    This invention provides novel lubricating oil compositions comprising an organometallic additive, including a metal selected from Groups I, Ib, and VIII of the Periodic System of Elements, e.g. Na, K, Cu, Co, Ni or Fe, chelated with the reaction product of formaldehyde, an amino acid and a phenol, dissolved in a lubricating oil. Depending on the choice of the metal, the above organometallic additive imparts rust inhibition, sludge dispersant, wear reduction and anti-oxidant properties to the lubricating oil compositions.

  10. Lubrication from mixture of boric acid with oils and greases

    SciTech Connect

    Erdemir, A.

    1995-07-11

    Lubricating compositions are disclosed including crystalline boric acid and a base lubricant selected from oils, greases and the like. The lubricity of conventional oils and greases can also be improved by adding concentrates of boric acid.

  11. Lubrication from mixture of boric acid with oils and greases

    SciTech Connect

    Erdemir, Ali

    1995-01-01

    Lubricating compositions including crystalline boric acid and a base lubricant selected from oils, greases and the like. The lubricity of conventional oils and greases can also be improved by adding concentrates of boric acid.

  12. Lubrication System with Tolerance for Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Portlock, Lawrence E. (Inventor); McCune, Michael E. (Inventor); Dobek, Louis J. (Inventor)

    2013-01-01

    A lubrication system includes an auxiliary lubricant tank 48, a supply conduit 58 extending from a source of lubricant 26 to the auxiliary lubricant tank. A reduced-G bypass line 108 branches from the conduit and enters the auxiliary tank at a first elevation E.sub.1. The system also includes an auxiliary tank discharge conduit 116, a portion of which resides within the tank. The resident portion has an opening 122 at least partially at a second elevation E.sub.2 higher than the first elevation.

  13. High-temperature seals and lubricants for geothermal rock bits. Final report

    SciTech Connect

    Hendrickson, R.R.; Winzenried, R.W.; Jones A.H.

    1981-04-01

    High temperature seals (elastomeric and mechanical) and lubricants were developed specifically for journal-type rock bits to be used in geothermal well drilling. Results at simulated downhole conditions indicate that five selected elastomeric seals (L'Garde No. 267, Utex Nos. 227, 231 and HTCR, and Sandia Glow Discharge Coated Viton) are capable of 288/sup 0/C (500/sup 0/F) service. Two prototype mechanical seals did not achieve the life determined for the elastomeric seals. Six lubricants (Pacer PLX-024 oil, PLX-043 oil, PLX-045 oil, Geobond Oil, and Geobond Grease) demonstrated 316/sup 0/C (600/sup 0/F) capability. Recommendation is made for full-scale simulated geothermal drilling tests utilizing the improved elastomeric seals and lubricants.

  14. Design of biomimetic super-lubricants by hydrogel-biopolymer aggregates

    NASA Astrophysics Data System (ADS)

    Seekell, Raymond; Dever, Rachel; Zhu, Yingxi

    2013-03-01

    Inspired by the superb lubricity of natural synovial fluids for moving articular cartilage joints, we investigate a biomimetic artificial lubricant based on a hydrogel-biopolymer mixture with optimized rheological properties at a microscopic level. Specifically, we examine the structure and rheological relationship of stimuli-responsive poly (N-isopropylacrylamide) (PNIPAM) hydrogel added with hyaluronic acid (HA) to simulate the complexes of HA with a globule protein, lubricin, which are credited as the two key lubricious constituents in natural synovial fluids. By combined microscopic structural characterization and rheology measurement, we tune the rheological and frictional behaviors of HA solutions by optimizing the content of added micron-sized PNIPAM hydrogel particles to form stable PNIPAM-HA network. In a recent work on using zwitterionic hydrogel particles instead of negatively charged PNIPAM, comparable structure and rheological properties of hydrogel-HA aggregates are observed, which may give insight to design new biocompatible lubricants and lubricious coatings for medical ramification.

  15. Evidence of a molecular boundary lubricant at snakeskin surfaces.

    PubMed

    Baio, Joe E; Spinner, Marlene; Jaye, Cherno; Fischer, Daniel A; Gorb, Stanislav N; Weidner, Tobias

    2015-12-01

    During slithering locomotion the ventral scales at a snake's belly are in direct mechanical interaction with the environment, while the dorsal scales provide optical camouflage and thermoregulation. Recent work has demonstrated that compared to dorsal scales, ventral scales provide improved lubrication and wear protection. While biomechanic adaption of snake motion is of growing interest in the fields of material science and robotics, the mechanism for how ventral scales influence the friction between the snake and substrate, at the molecular level, is unknown. In this study, we characterize the outermost surface of snake scales using sum frequency generation (SFG) spectra and near-edge X-ray absorption fine structure (NEXAFS) images collected from recently shed California kingsnake (Lampropeltis californiae) epidermis. SFG's nonlinear optical selection rules provide information about the outermost surface of materials; NEXAFS takes advantage of the shallow escape depth of the electrons to probe the molecular structure of surfaces. Our analysis of the data revealed the existence of a previously unknown lipid coating on both the ventral and dorsal scales. Additionally, the molecular structure of this lipid coating closely aligns to the biological function: lipids on ventral scales form a highly ordered layer which provides both lubrication and wear protection at the snake's ventral surface. PMID:26655468

  16. QCM Studies of Alcohols as Vapor Phase Lubricants for MEMS

    NASA Astrophysics Data System (ADS)

    Nemetz, Heather; Jones, Jon; Coffey, Tonya

    2006-11-01

    The future of nanotechnology depends in part upon the development of successful lubrication for micromachines (MEMS). Atomic Force Microscopy (AFM) research at Pennsylvania State University* has suggested alcohols such as propanol, ethanol, butanol, and pentanol to be potential vapor phase lubricants for MEMS; propanol at its vapor pressure can greatly reduce the friction on silicon dioxide surfaces. Due to the relatively high vapor pressure of these alcohols, all surfaces of a MEMS, including buried interfaces not easily reached by solid coatings, should become coated in thin layers of the alcohol upon exposure. We are testing the ability of the alcohols to migrate to buried interfaces in the MEMS. The mass uptake of the alcohols will be measured using the quartz crystal microbalance (QCM) in a vacuum chamber. The resonant frequency of the QCM drops as alcohols adsorb on its face. The uptake of the alcohols is measured as the pressure increases using different geometries of the cans, allowing us to simulate a buried interface. The aforementioned alcohols are first thermally distilled, then leaked into the chamber until vapor pressure of the alcohol is reached. We see significant mass uptake even in extreme geometries, where the entire QCM face is only accessible through a tiny hole in the can encasing the QCM, 0.0006'' in diameter. *K. Strawhecker et al., Trib. Lett. 19, 17 (2005).

  17. A Review of Tribological Coatings for Control Drive Mechanisms in Space Reactors

    SciTech Connect

    CJ Larkin; JD Edington; BJ Close

    2006-02-21

    Tribological coatings must provide lubrication for moving components of the control drive mechanism for a space reactor and prevent seizing due to friction or diffusion welding to provide highly reliable and precise control of reflector position over the mission lifetime. Several coatings were evaluated based on tribological performance at elevated temperatures and in ultrahigh vacuum environments. Candidates with proven performance in the anticipated environment are limited primarily to disulfide materials. Irradiation data for these coatings is nonexistent. Compatibility issues between coating materials and structural components may require the use of barrier layers between the solid lubricant and structural components to prevent deleterious interactions. It would be advisable to consider possible lubricant interactions prior to down-selection of structural materials. A battery of tests was proposed to provide the necessary data for eventual solid lubricant/coating selection.

  18. Influence of liquid lubricant properties on their performance

    NASA Technical Reports Server (NTRS)

    Wedeven, V.

    1972-01-01

    The influence of lubricant properties on performance is considered in connection with various mechanisms of lubrication. The effects of temperature and pressure on viscosity, which is important in hydrodynamic and elastohydrodynamic lubrication, is presented using a correlation postulated by Roelands. Under elastohydrodynamic conditions it is important to distinguish between the influence of lubricant properties within the inlet region and the Hertz region since each performs different functions. The role of lubricant transport properties such as surface tension is considered in connection with lubricant starvation. Since the lubrication of practical surfaces usually involves boundary as well as hydrodynamic mechanisms, both the chemical and physical properties significantly influence the lubricant's performance.

  19. Self-lubricating polymer composites and polymer transfer film lubrication for space applications

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1990-01-01

    The use of self-lubricating polymers and polymer composites in space is somewhat limited today. In general, they are only used when other methods are inadequate. There is potential, however, for these materials to make a significant impact on future space missions if properly utilized. Some of the different polymers and fillers used to make self-lubricating composites are surveyed. The mechanisms of composite lubrication and wear, the theory behind transfer film lubricating mechanisms, and some factors which affect polymer composite wear and transfer are examined. In addition, some of the current space tribology application areas for self-lubricating polymer composites and polymer transfer are mentioned.

  20. Surface functionalization by fine ultraviolet-patterning of nanometer-thick liquid lubricant films

    NASA Astrophysics Data System (ADS)

    Lu, Renguo; Zhang, Hedong; Komada, Suguru; Mitsuya, Yasunaga; Fukuzawa, Kenji; Itoh, Shintaro

    2014-11-01

    For micro/nanoscale devices, surface functionalization is essential to achieve function and performance superior to those that originate from the inherent bulk material properties. As a method of surface functionalization, we dip-coated nanometer-thick liquid lubricant films onto solid surfaces and then patterned the lubricant films with ultraviolet (UV) irradiation through a photomask. Surface topography, adhesion, and friction measurements demonstrated that the patterned films feature a concave-convex thickness distribution with thicker lubricant in the irradiated regions and a functional distribution with lower adhesion and friction in the irradiated convex regions. The pattern linewidth ranged from 100 to as fine as 0.5 μm. The surface functionalization effect of UV-patterning was investigated by measuring the water contact angles, surface energies, friction forces, and depletion of the patterned, as-dipped, and full UV-irradiated lubricant films. The full UV-irradiated lubricant film was hydrophobic with a water contact angle of 102.1°, and had lower surface energy, friction, and depletion than the as-dipped film, which was hydrophilic with a water contact angle of 80.7°. This demonstrates that UV irradiation substantially improves the surface and tribological properties of the nanometer-thick liquid lubricant films. The UV-patterned lubricant films exhibited superior surface and tribological properties than the as-dipped film. The water contact angle increased and the surface energy, friction, and depletion decreased as the pattern linewidth decreased. In particular, the 0.5-μm patterned lubricant film even showed a larger water contact angle and lower friction and depletion than the full UV-irradiated film. These indicate that UV-patterning of nanometer-thick lubricant films with a minimized linewidth has a better surface functionalization effect than full UV irradiation. Enhancement of the surface functionalization effect may be attributed to a

  1. Role of uppermost superficial surface layer of articular cartilage in the lubrication mechanism of joints

    PubMed Central

    KUMAR, P.; OKA, M.; TOGUCHIDA, J.; KOBAYASHI, M.; UCHIDA, E.; NAKAMURA, T.; TANAKA, K.

    2001-01-01

    The uppermost superficial surface layer of articular cartilage, the ‘lamina splendens’ which provides a very low friction lubrication surface in articular joints, was investigated using atomic force microscopy (AFM). Complementary specimens were also observed under SEM at −10 °C without dehydration or sputter ion coating. Fresh adult pig osteochondral specimens were prepared from the patellas of pig knee joints and digested with the enzymes, hyaluronidase, chondroitinase ABC and alkaline protease. Friction coefficients between a pyrex glass plate and the osteochondral specimens digested by enzymes as well as natural (undigested) specimens were measured, using a thrust collar apparatus. Normal saline, hyaluronic acid (HA) and a mixture of albumin, globulin, HA (AGH) were used as lubrication media. The surface irregularities usually observed in SEM studies were not apparent under AFM. The articular cartilage surface was resistant to hyaluronidase and also to chondroitinase ABC, but a fibrous structure was exhibited in alkaline protease enzymes-digested specimens. AFM analysis revealed that the thickness of the uppermost superficial surface layer of articular cartilage was between 800 nm and 2 μm in adult pig articular cartilage. The coefficient of friction (c.f.) was significantly higher in chondroitinase ABC and alkaline protease enzymes digested specimens. Generally, in normal saline lubrication medium, c.f. was higher in comparison to HA and AGH lubrication media. The role of the uppermost, superficial surface layer of articular cartilage in the lubrication mechanism of joints is discussed. PMID:11554503

  2. Role of uppermost superficial surface layer of articular cartilage in the lubrication mechanism of joints.

    PubMed

    Kumar, P; Oka, M; Toguchida, J; Kobayashi, M; Uchida, E; Nakamura, T; Tanaka, K

    2001-09-01

    The uppermost superficial surface layer of articular cartilage, the 'lamina splendens' which provides a very low friction lubrication surface in articular joints, was investigated using atomic force microscopy (AFM). Complementary specimens were also observed under SEM at -10 degrees C without dehydration or sputter ion coating. Fresh adult pig osteochondral specimens were prepared from the patellas of pig knee joints and digested with the enzymes, hyaluronidase, chondroitinase ABC and alkaline protease. Friction coefficients between a pyrex glass plate and the osteochondral specimens digested by enzymes as well as natural (undigested) specimens were measured, using a thrust collar apparatus. Normal saline, hyaluronic acid (HA) and a mixture of albumin, globulin, HA (AGH) were used as lubrication media. The surface irregularities usually observed in SEM studies were not apparent under AFM. The articular cartilage surface was resistant to hyaluronidase and also to chondroitinase ABC, but a fibrous structure was exhibited in alkaline protease enzymes-digested specimens. AFM analysis revealed that the thickness of the uppermost superficial surface layer of articular cartilage was between 800 nm and 2 microm in adult pig articular cartilage. The coefficient of friction (c.f.) was significantly higher in chondroitinase ABC and alkaline protease enzymes digested specimens. Generally, in normal saline lubrication medium, c.f. was higher in comparison to HA and AGH lubrication media. The role of the uppermost, superficial surface layer of articular cartilage in the lubrication mechanism of joints is discussed. PMID:11554503

  3. LUBRICATED TRANSPORT OF VISCOUS FLUIDS

    SciTech Connect

    JOSEPH, DANIEL D

    2004-06-21

    We became the acknowledged world leaders in the science fundamentals of the technology of water lubricated pipelines focusing on stability, numerical and experimental studies. We completed the first direct numerical simulation of axisymmetric core flow. We showed that the pressure at the front of the wave is large (the fluid enters a converging region) and it pushes the interface in, steepening the wave at its front. At the backside of the wave, behind the crest, the pressure is low (diverging flow) and it pulls the interface to the wall, smoothing the backside of the wave. The steepening of the wave can be regarded as a shock up by inertia and it shows that dynamics works against the formation of long waves which are often assumed but not justified in the analysis of such problems. We showed that the steep wave persists even as the gap between the core and the wall decreases to zero. The wave length also decreases in proportion, so that the wave shape is preserved in this limit. This leads to the first mathematical solution giving rise sharkskin. The analysis also showed that there is a threshold Reynolds number below which the total force reckoned relative to a zero at the wave crest is negative, positive above, and we conjectured, therefore that inertia is required to center a density matched core and to levitate the core off the wall when the density is not matched. Other work relates to self-lubricated transport of bitumen froth and self-lubricated transport of bitumen froth.

  4. 14 CFR 33.39 - Lubrication system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.39 Lubrication system. (a) The lubrication system of the engine must be designed and constructed so that it...

  5. Glass molding process with mold lubrication

    DOEpatents

    Davey, Richard G.

    1978-06-27

    Improvements are provided in glass forming processes of the type wherein hot metal blank molds are employed by using the complementary action of a solid film lubricant layer, of graphite dispersed in a cured thermoset organopolysiloxane, along with an overspray of a lubricating oil.

  6. Positive commandable oiler for satellite bearing lubrication

    NASA Technical Reports Server (NTRS)

    James, G. E.

    1977-01-01

    On-orbit commandable lubrication of ball bearings accomplished by direct oil application to the moving ball surfaces was studied. Test results for the lubricant applicator portion of the system are presented in conjunction with a design approach for the reservoir and metering components.

  7. Pressure-viscosity coefficient of biobased lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Film thickness is an important tribological property that is dependent on the combined effect of lubricant properties, material property of friction surfaces, and the operating conditions of the tribological process. Pressure-viscosity coefficient (PVC) is one of the lubricant properties that influe...

  8. 30 CFR 56.14204 - Machinery lubrication.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Machinery lubrication. 56.14204 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Machinery and Equipment Safety Practices and Operational Procedures § 56.14204 Machinery lubrication. Machinery...

  9. 30 CFR 57.14204 - Machinery lubrication.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Machinery lubrication. 57.14204 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Machinery and Equipment Safety Practices and Operational Procedures § 57.14204 Machinery lubrication. Machinery...

  10. 40 CFR 1065.740 - Lubricants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Fluids, Test Fuels, Analytical Gases and Other Calibration Standards § 1065.740 Lubricants... engine in use. (b) You may use lubrication additives, up to the levels that the additive...

  11. Biobased, environmentally friendly lubricants for processing plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetable oil based lubricants have excellent lubricity, biodegradability, good viscosity temperature characteristics and low evaporation loss, but poor thermos-oxidative stability and cold flow properties. This paper presents a systematic approach to improve the oxidative and cold flow behavior of...

  12. Control Methods of Operational Properties of Lubricants

    NASA Astrophysics Data System (ADS)

    Lysyannikova, N.; Kovalski, B.; Bezborodov, Yu; Lysyannikov, A.; Kravtsova, Ye; Shram, V.; Kovaleva, M.

    2016-06-01

    Some results of thermal-oxidation and temperature stability testing of motor oils are presented. The catalytic influence of metals on oxidizing processes in lubricants with use of steel 45 was determined. The parameters for identification of oils by groups of operational properties and quantity indicators of the influence of metals on oxidizing processes of lubricants are offered.

  13. Bearing, gearing, and lubrication technology

    NASA Technical Reports Server (NTRS)

    Anderson, W. J.

    1978-01-01

    Results of selected NASA research programs on rolling-element and fluid-film bearings, gears, and elastohydrodynamic lubrication are reported. Advances in rolling-element bearing material technology, which have resulted in a significant improvement in fatigue life, and which make possible new applications for rolling bearings, are discussed. Research on whirl-resistant, fluid-film bearings, suitable for very high-speed applications, is discussed. An improved method for predicting gear pitting life is reported. An improved formula for calculating the thickness of elastohydrodynamic films (the existence of which help to define the operating regime of concentrated contact mechanisms such as bearings, gears, and cams) is described.

  14. A High Temperature Vapor Phase Lubrication Study Utilizing a Thioether Liquid Lubricant

    NASA Technical Reports Server (NTRS)

    Morales, Wilfredo; Graham, E. Earl; Galvin, Thomas

    1997-01-01

    Much of the experimental work on vapor phase lubrication has employed certain organo phosphorous compounds as the vapor phase lubricant. Graham and Klaus, for instance, used tricresyl phosphate (TCP) and tributyl phosphate to vapor phase lubricate a four-ball wear tester using M50 steel balls at 370 C. Makki and Graham were able to vapor phase lubricate a reciprocating pin on plate tribometer using 1018 steel at 280 C with TCP vapor. Although a few organo phosphorous compounds, such as TCP, have been successfully used as vapor phase lubricants in many laboratory experiments, many problems remain unsolved. Two areas of concern relate to the 'durability' of phosphate deposited films and to the ability of the lubricating system to "self-recover" when vapor phase lubricated with an organo phosphorous compound. Durability refers to the ability of the deposited film to provide effective lubrication, for a period of time, after the vapor flow to the lubricating surfaces has been interrupted. Vapor phase lubrication tests, conducted at Cleveland State University with their high temperature tribometer, revealed that when TCP vapor flow to the lubricating surfaces was interrupted the frictional coefficient of the system rapidly increased from a value less than 0.1 to a value of 0.3 which was selected as our failure point. Self-recovery means the ability of the vapor phase lubricant to reduce the frictional coefficient of the lubricating system back down to value less than 0.1 after startup of the interrupted vapor flow. Lubrication tests conducted at Cleveland State University revealed that the high temperature tribometer could not self-recover after startup of the interrupted TCP vapor flow.

  15. Tribological challenges in MEMS and their mitigation via vapor phase lubrication

    NASA Astrophysics Data System (ADS)

    Dugger, Michael T.

    2011-06-01

    MicroElectroMechanical Systems (MEMS) have become commercially successful in a number of niche applications. However, commercial success has only been possible where design, operating conditions, and materials result in devices that are not very sensitive to tribological effects. The use of MEMS in defense and national security applications will typically involve more challenging environments, with higher reliability and more complex functionality than required of commercial applications. This in turn will necessitate solutions to the challenges that have plagued MEMS since their inception - namely, adhesion, friction and wear. Adhesion during fabrication and immediately post-release has largely been resolved using hydrophobic coatings, but these coatings are not mechanically durable and do not inhibit surface degradation during extended operation. Tribological challenges in MEMS and approaches to mitigate the effects of adhesion, friction and wear are discussed. A new concept for lubrication of silicon MEMS using gas phase species is introduced. This "vapor phase lubrication" process has resulted in remarkable operating life of devices that rely on mechanical contact. VPL is also an effective lubrication approach for materials other than silicon, where traditional lubrication approaches are not feasible. The current status and remaining challenges for maturation of VPL are highlighted.

  16. Solid/liquid lubrication of ceramics at elevated temperatures

    SciTech Connect

    Erdemir, A.; Erck, R.A.; Fenske, G.R.; Hong, H.

    1996-04-01

    This study investigates the effect of solid and liquid lubrication on friction and wear performance of silicon nitride (Si{sub 3}N{sub 4}) and cast iron. The solid lubricant was a thin silver film ({approx}2 {mu}m thick) produced on Si{sub 3}N{sub 4} by ion-beam-assisted deposition. A high-temperature polyol-ester-base synthetic oil served as the liquid lubricant. Friction and wear tests were performed with pin-on-disk and oscillating-slider wear test machines at temperatures up to 300{degrees}C. Without the silver films, the friction coefficients of Si{sub 3}N{sub 4}/Si{sub 3}N{sub 4} test pairs were 0.05 to 0.14, and the average wear rates of Si{sub 3}N{sub 4} pins were {approx}5 x 10{sup -8} mm{sup 3} N{sup -1}. The friction coefficients of Si{sub 3}N{sub 4}/cast iron test pairs ranged from 0.08 to 0.11, depending on test temperature. The average specific wear rates of cast iron pins were {approx}3 x 10{sup -7} mm{sup 3} N{sup -1} m{sup -1}. However, simultaneous use of the solid-lubricant silver and synthetic oil on the sliding surfaces reduced friction coefficients to 0.02 to 0.08. Moreover, the wear of Si{sub 3}N{sub 4} pins and silver-coated Si{sub 3}N{sub 4} disks was so low that it was difficult to assess by a surface profilometer. The wear rates of cast iron pins were {approx}7 x 10{sup -9} mm{sup 3} N{sup -1} m{sup -1} up to 250{degrees}C, but showed a tendency to increase slightly at much higher temperatures. In general, the test results demonstrated that the solid/liquid lubrication of ceramic and/or metallic components is both feasible and effective in controlling friction and wear.

  17. Asperity lubrication and cavitation in face seals

    NASA Technical Reports Server (NTRS)

    Walowitt, J. A.

    1974-01-01

    The basic aspect of parallel-surface lubrication that distinguishes it from other areas of lubrication technology is that classical lubrication theory does not predict the existence of a stable hydrodynamic film for steady-state, isothermal, incompressible flow between smooth, parallel surfaces. Hydrodynamic films between apparently parallel surfaces have been observed in practice and are often essential for the reliable performance of thrust bearings and seals. In order to account for this fortunate discrepancy between classical theory and experiment, load-support mechanisms relating to accidential features characteristic of seal performance, which relax one or more of the assumptions in the classical theory and permit the theoretical prediction of load support are proposed. Some of the features that have been analyzed are vibratory effects such as wobble and bounce, surface waviness, nonsymmetric rotation resulting from various types of misalignment, lubricant density change, non-Newtonian lubricant effects, and surface roughness.

  18. Evaluation of outer race tilt and lubrication on ball wear and SSME bearing life reductions

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Merriman, T. L.; Stockwell, R. D.; Dufrane, K. F.

    1983-01-01

    Several aspects of the SSME bearing operation were evaluated. The possibility of elastohydrodynamics (EHD) lubrication with a cryogenic fluid was analyzed. Films as thick as .61 microns were predicted with one theory which may be thick enough to provide hydrodynamic support. The film formation, however, is heavily dependent on good surface finish and a low bulk bearing temperature. Bearing dynamics to determine if the radial stiffness of a bearing which are dependent on bearing misalignment were analyzed. Four ball tests were conducted at several environmental conditions from an LN2 bath to 426 C in air. Surface coatings and ball materials are evaluated. Severe wear and high friction are measured for all ball materials except when the balls have surface lubricant coatings.

  19. The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.; DellaCorte, Christopher

    2001-01-01

    Foil air bearing load capacity tests were conducted to investigate if a solid lubricant coating applied to the surface of the bearing's top foil can function as a break-in coating. Two foil coating materials, a conventional soft polymer film (polyimide) and a hard ceramic (alumina), were independently evaluated against as-ground and worn (run-in) journals coated with NASA PS304, a high-temperature solid lubricant composite coating. The foil coatings were evaluated at journal rotational speeds of 30,000 rpm and at 25 C. Tests were also performed on a foil bearing with a bare (uncoated) nickel-based superalloy top foil to establish a baseline for comparison. The test results indicate that the presence of a top foil solid lubricant coating is effective at increasing the load capacity performance of the foil bearing. Compared to the uncoated baseline, the addition of the soft polymer coating on the top foil increased the bearing load coefficient by 120% when operating against an as-ground journal surface and 85 percent against a run-in journal surface. The alumina coating increased the load coefficient by 40% against the as-ground journal but did not have any affect when the bearing was operated with the run-in journal. The results suggest that the addition of solid lubricant films provide added lubrication when the air film is marginal indicating that as the load capacity is approached foil air bearings transition from hydrodynamic to mixed and boundary lubrication.

  20. Brush seal shaft wear resistant coatings

    NASA Astrophysics Data System (ADS)

    Howe, Harold

    1995-03-01

    Brush seals suffer from high wear, which reduces their effectiveness. This work sought to reduce brush seal wear by identifying and testing several industry standard coatings. One of the coatings was developed for this work. It was a co-sprayed PSZ with boron-nitride added for a high temperature dry lubricant. Other coatings tested were a PSZ, chrome carbide and a bare rotor. Testing of these coatings included thermal shocking, tensile testing and wear/coefficient of friction testing. Wear testing consisted of applying a coating to a rotor and then running a sample tuft of SiC ceramic fiber against the coating. Surface speeds at point of contact were slightly over 1000 ft/sec. Rotor wear was noted, as well as coefficient of friction data. Results from the testing indicates that the oxide ceramic coatings cannot withstand the given set of conditions. Carbide coatings will not work because of the need for a metallic binder, which oxidizes in the high heat produced by friction. All work indicated a need for a coating that has a lubricant contained within itself and the coating must be resistant to an oxidizing environment.

  1. Double angle seal forming lubricant film

    DOEpatents

    Ernst, William D.

    1984-01-01

    A lubricated piston rod seal which inhibits gas leaking from a high pressure chamber on one side of the seal to a low pressure chamber on the other side of the seal. A liquid is supplied to the surface of the piston rod on the low pressure side of the seal. This liquid acts as lubricant for the seal and provides cooling for the rod. The seal, which can be a plastic, elastomer or other material with low elastic modulus, is designed to positively pump lubricant through the piston rod/seal interface in both directions when the piston rod is reciprocating. The capacity of the seal to pump lubricant from the low pressure side to the high pressure side is less than its capacity to pump lubricant from the high pressure side to the low pressure side which ensures that there is zero net flow of lubricant to the high pressure side of the seal. The film of lubricant between the seal and the rod minimizes any sliding contact and prevents the leakage of gas. Under static conditions gas leakage is prevented by direct contact between the seal and the rod.

  2. Mechanism of lubrication by tricresylphosphate (TCP)

    NASA Technical Reports Server (NTRS)

    Faut, O. D.; Wheeler, D. R.

    1983-01-01

    A pin-on-disk tribometer equipped with an induction heater was used to study the coefficient of friction as a function of temperature for tricresylphosphate (TCP) on continuous vacuum melted (CVM) M-50 tool steel when the TCP was present in a liquid reservoir (bulk lubrication), and when it was applied as a liquid layer directly to the disk (limited lubrication). Under limited lubrication conditions, experiments were performed in dry ( 100 ppm H2O) air, dry ( 20 ppm H2O) nitrogen, dry nitrogen with the disks heated to 700 C then cooled to room temperature before the TCP was applied and the measurements made (preheated disks), and moist nitrogen using preheated disks. When the coefficient of friction was plotted as a function of the disk temperature, the friction decreased at a characteristic temperature, T sub r whose observed values were 265 C for bulk lubrication conditions in dry air, 225 C for limited lubrication conditions in dry air, and 215 C for limited lubrication conditions in dry nitrogen. No decrease in friction was observed with preheated disks; instead a sharp failure temperature was observed at 218 C, which was taken as the temperature about which the behavior of TCP should be judged, X-ray photoelectron spectroscopy confirmed the presence of phosphate on the surface of the iron pins used in the tribometer under TCP lubrication. Depth profile studies support the idea that a chemical reaction occurs between the TCP and the metal surface at T sub r.

  3. Modelling of heavily loaded lubricated contacts

    NASA Astrophysics Data System (ADS)

    Sadeghi, Farshid; McClug, William D., Jr.; Kim, Kyung-Hoon; Osborn, Kevin; Lance, Brian

    1992-02-01

    Thermal elastohydrodynamic (EHD) lubrication of rolling/sliding line contacts is investigated to develop an interactive computer program for prediction of lubrication system performance. The user inputs lubricant and mechanical system physical properties as well as operating conditions of load and speed for calculation of contact zone pressure, temperature, traction, and stresses. This program is one of the first to include thermal effects in calculations and, therefore, can more accurately assess the critical tribological performance parameters at high load and speed conditions than previous prediction models. The program is written in the FORTRAN language and utilizes a UNIX operating system for high quality graphic output allowing easy visualization of results.

  4. NASA PS304 Lubricant Tested in World's First Commercial Oil-Free Gas Turbine

    NASA Technical Reports Server (NTRS)

    Weaver, Harold F.

    2003-01-01

    In a marriage of research and commercial technology, a 30-kW Oil-Free Capstone microturbine electrical generator unit has been installed and is serving as a test bed for long-term life-cycle testing of NASA-developed PS304 shaft coatings. The coatings are used to reduce friction and wear of the turbine engine s foil air bearings during startup and shut down when sliding occurs, prior to the formation of a lubricating air film. This testing supports NASA Glenn Research Center s effort to develop Oil-Free gas turbine aircraft propulsion systems, which will employ advanced foil air bearings and NASA s PS304 high temperature solid lubricant to replace the ball bearings and lubricating oil found in conventional engines. Glenn s Oil-Free Turbomachinery team s current project is the demonstration of an Oil-Free business jet engine. In anticipation of future flight certification of Oil-Free aircraft engines, long-term endurance and durability tests are being conducted in a relevant gas turbine environment using the Capstone microturbine engine. By operating the engine now, valuable performance data for PS304 shaft coatings and for industry s foil air bearings are being accumulated.

  5. Elastohydrodynamic Lubrication with Polyolester Lubricants and HFC Refrigerants, Final Report, Volume 2

    SciTech Connect

    Gunsel, Selda; Pozebanchuk, Michael

    1999-04-01

    Lubrication properties of refrigeration lubricants were investigated in high pressure nonconforming contacts under different conditions of temperature, rolling speed, and refrigerant concentration. The program was based upon the recognition that the lubrication regime in refrigeration compressors is generally elastohydrodynamic or hydrodynamic, as determined by the operating conditions of the compressor and the properties of the lubricant. Depending on the compressor design, elastohydrodynamic lubrication conditions exist in many rolling and sliding elements of refrigeration compressors such as roller element bearings, gears, and rotors. The formation of an elastohydrodynamic film separating rubbing surfaces is important in preventing the wear and failure of compressor elements. It is, therefore, important to predict the elastohydrodynamic (EHD) performance of lubricants under realistic tribocontact renditions. This is, however, difficult as the lubricant properties that control film formation are critically dependent upon pressure and shear, and cannot be evaluated using conventional laboratory instruments. In this study, the elastohydrodynamic behavior of refrigeration lubricants with and without the presence of refrigerants was investigated using the ultrathin film EHD interferometry technique. This technique enables very thin films, down to less than 5 nm, to be measured accurately within an EHD contact under realistic conditions of temperature, shear, and pressure. The technique was adapted to the study of lubricant refrigerant mixtures. Film thickness measurements were obtained on refrigeration lubricants as a function of speed, temperature, and refrigerant concentration. The effects of lubricant viscosity, temperature, rolling speed, and refrigerant concentration on EHD film formation were investigated. From the film thickness measurements, effective pressure-viscosity coefficients were calculated. The lubricants studied in this project included two

  6. Starved elastohydrodynamic lubricated elliptical contacts

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1980-01-01

    A theoretical study of the influence of lubricant starvation on film thickness and pressure in hard and soft elliptical elastohydrodynamic contacts is presented. From the results for both hard and soft EHL contacts a simple and important dimensionless inlet boundary distance is specified. This inlet boundary defines whether a fully flooded or a starved condition exists in the contact. Furthermore it is found that the film thickness for a starved condition could be written in dimensionless terms as a function of the inlet distance parameter and the film thickness for a fully flooded condition. Contour plots of pressure and film thickness in and around the contact are shown for fully flooded and starved conditions. The theoretical findings are compared directly with results obtained experimentally.

  7. Solvent dewaxing of lubricating oils

    SciTech Connect

    Sequeira, A. Jr.

    1991-04-09

    This paper describes improvement in a process for producing a dewaxed lubricating oil from a wax-bearing mineral oil by the steps comprising; mixing the oil with a dewaxing solvent thereby forming an oil-solvent mixture, chilling the oil-solvent mixture to a dewaxing temperature thereby crystallizing the wax and forming an oil-solvent crystalline wax mixture, separating the oil-solvent-crystalline wax mixture to form a dewaxed oil-solvent mixture and crystalline wax, steam stripping the dewaxed oil-solvent mixture at a temperature of 300{degrees}F to 600{degrees}F and pressure of 1 atm to 3 atm, to yield a solvent free dewaxed oil.

  8. The basics of powder lubrication in high-temperature powder-lubricated dampers

    SciTech Connect

    Heshmat, H.; Walton, J.F. )

    1993-04-01

    The objective of this investigation is to develop a novel powder-lubricated rotor bearing system damper concept for use in high-temperature, high-speed rotating machinery such as advanced aircraft gas turbine engines. The approach discussed herein consists of replacing a conventional oil lubrication or frictional damper system with a powder lubrication system that uses the process particulates or externally fed powder lubricant. Unlike previous work in this field, this approach is based on the postulate of the quasi-hydrodynamic nature of powder lubrication. This postulate is deduced from past observation and present verification that there are a number of basic features of powder flow in narrow interfaces that have the characteristic behavior of fluid film lubrication. In addition to corroborating the basic mechanism of powder lubrication, the conceptual and experimental work performed in this program provides guidelines for selection of the proper geometries, materials, and powders suitable for this tribological process. The present investigation describes the fundamentals of quasi-hydrodynamic powder lubrication and defines the rationale underlying the design of the test facility. The performance and the results of the experimental program present conclusions reached regarding design requirements as well as the formulation of a proper model of quasi-hydrodynamic powder lubrication.

  9. Lubrication theory of drag on a scanning probe in structured water, near a hydrophilic surface.

    PubMed

    Feibelman, Peter J

    2006-02-28

    The drag is evaluated, in lubrication theory, on a parabolic-cylindrical tip moving parallel to a flat sample, in water, close enough that the presumed nanometer-thick, structured-water, "interphase" coatings of both it and the sample overlap. Assuming coatings of width, w, and of viscosity, eta, much larger than bulk water's, the friction force is predicted to equal -2pietacRphi(D/2w), where R is the tip's radius of curvature, c is its speed, D is the tip-sample separation, and Phi is a universal function whose value only differs noticeably from ln(2w/D) for D < w.

  10. Lubrication flow between a cavity and a flexible wall

    NASA Astrophysics Data System (ADS)

    Yin, Xiuyan; Kumar, Satish

    2005-06-01

    Lubrication flows near deformable solid boundaries occur in a diverse range of settings including coating and printing processes, biological systems, and suspensions. In order to examine the effect of surface topography on the elastohydrodynamic interactions that arise in these flows, the flow between a rigid cavity and a flexible wall is studied. Reynolds equation for the fluid is coupled to a model for the wall which is backed by a series of springs and/or held by a uniform tension force. The resulting nonlinear ordinary differential equations are then solved numerically to obtain pressure profiles and wall positions. When the wall modulus or tension is large relative to viscous forces, the wall hardly deforms and both a pressure mountain and valley are observed due to the gap change produced by the cavity topography. When the wall modulus and tension are small relative to viscous forces, the wall easily deforms and assumes a shape similar to that of the cavity. The pressure profiles are also dramatically altered and in some cases show only a valley without a mountain. Cavity shape is found to have a significant influence on both the pressure profiles and the wall deformation. The results suggest that surface topography may significantly modify the elastohydrodynamic interactions that arise in lubrication flows near deformable solid boundaries.

  11. Materials and lubrication for gear and bearing surfaces in uhv

    SciTech Connect

    Kirby, R.E.; Collet, G.J.; Garwin, E.L.

    1980-06-01

    During design and construction of the SLAC polarized LEED (PLEED) system, a search was made for a dependable gear, bearing, and lubrication system for the computer-controlled Faraday cup used to measure diffracted beams. Components must be nonmagnetic, bakeable to 250/sup 0/C, and at room temperature must operate at pressures in the 10/sup -9/ to 10/sup -10/ Pa range. A test system was constructed which incorporated a meshed pair of dissimilar pitch diameter spur gears, one of which was confined to (by bushings) and rotated on a fixed shaft, while the other gear was driven by a commercial rotary motion feedthrough which was rotated by a servo motor driven in sine fashion with a direction reversal every six turns and peak speeds of 50 rpm. The criterion for a successful pair was approx. 10/sup 5/ turns, the life rating for the feedthrough. Pairs had actual turn counts from less than 1 to 91,000. Materials for gears included stainless steel, beryllium copper, and aluminum alloys. Lubricants used singly and in concert were MoS/sub 2/, WS/sub 2/, Ag, hard chrome, and a MoS/sub 2/-graphite-sodium silicate mixture. The successful gear pair was Ag-plated Al alloy and MoS/sub 2/-graphite-sodium silicate-coated Be-Cu. Subsequent performance in the PLEED system after repeated bakeouts will also be discussed.

  12. Anti-wear properties of Cr C and Ni Co alloy coatings as substitutes for conventional nanocrystalline Cr coatings

    NASA Astrophysics Data System (ADS)

    Zeng, Zhixiang; Zhang, Junyan

    2008-09-01

    Nanocrystalline Ni-Co, amorphous Cr-C alloy and nanocrystalline Cr-C coatings were electrodeposited from 'environmentally acceptable' electrolytes as potential substitutes for conventional nanocrystalline Cr coatings electrodeposited from noxious hexavalent chromium. The structure, morphology and hardness of coatings are investigated using a transmission electron microscope, a scanning electronic microscope and a Vickers hardness tester, respectively. Anti-wear properties are tested on a pin-on-plate vibrant wear tester. The correlation between the wear resistance, hardness, brittleness and the lubricated state is investigated. The results show that the wear behaviour of specimens significantly depends on their lubricated state, hardness and brittleness. Under the lubricated sliding condition, abrasive wear is the primary wear mechanism for all specimens. With respect to the abrasive wear mechanism, both the elastic and plastic deformations play important roles during the lubricated sliding process. Thus, the amorphous and nanocrystalline Cr-C alloy coatings, with both high brittleness and high hardness, exhibit a lower wear rate than the conventional Cr and Ni-Co coatings. On the other hand, under the dry sliding condition, the annealed Ni-Co coating, with an excellent compromise between high hardness and toughness, exhibits an abrasive wear mechanism and a relatively low wear rate; in contrast, the brittle Cr-matrix coatings exhibit a severe fatigue/delamination wear mechanism and high wear rate.

  13. Anti-ice coating inspired by ice skating.

    PubMed

    Chen, Jing; Luo, Zhiqiang; Fan, Qinrui; Lv, Jianyong; Wang, Jianjun

    2014-11-01

    Accumulation of ice to surfaces brings dangerous and costly problems to our daily life. In this paper, an anti-ice coating inspired by ice skating is reported. Hyaluronic acid is used in the anti-ice coating to form aqueous lubricating layer benefitting from its high water absorbing property. Dopamine, the main component of the mussel adhesive protein, is introduced to anchor the hyaluronic acid to the solid surfaces to render the coating applicable to all types of solid surfaces. At the same time it serves as the crosslinking agent for hyaluronic acid, thus the thickness of the water collecting film could be easily varied. Ice adhesion strength on surfaces coated with such kind of coating could be more than one order of magnitude lower than that of uncoated ones. The results indicate that this anti-ice coating with the aqueous lubricating layer has great potential for fighting against icing problems.

  14. Compatibility of refrigerants and lubricants with elastomers

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.

    1992-07-01

    Information contained in this reporters designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. Swell measurements have been made on approximately 50% of the proposed elastomers (94 total)in both the lubricant (7 total) and refrigerant (10 total) materials. Swell behavior in the these fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  15. Microfog lubrication for aircraft engine bearings

    NASA Technical Reports Server (NTRS)

    Rosenlieb, J. W.

    1976-01-01

    An analysis and system study was performed to provide design information regarding lubricant and coolant flow rates and flow paths for effective utilization of the lubricant and coolant in a once through bearing oil mist (microfog) and coolant air system. Both static and dynamic tests were performed. Static tests were executed to evaluate and calibrate the mist supply system. A total of thirteen dynamic step speed bearing tests were performed using four different lubricants and several different mist and air supply configurations. The most effective configuration consisted of supplying the mist and the major portion of the cooling air axially through the bearing. The results of these tests have shown the feasibility of using a once through oil mist and cooling air system to lubricate and cool a high speed, high temperature aircraft engine mainshaft bearing.

  16. Liquid lubricants for advanced aircraft engines

    NASA Technical Reports Server (NTRS)

    Loomis, William R.; Fusaro, Robert L.

    1992-01-01

    An overview of liquid lubricants for use in current and projected high performance turbojet engines is discussed. Chemical and physical properties are reviewed with special emphasis placed on the oxidation and thermal stability requirements imposed upon the lubrication system. A brief history is given of the development of turbine engine lubricants which led to the present day synthetic oils with their inherent modification advantages. The status and state of development of some eleven candidate classes of fluids for use in advanced turbine engines are discussed. Published examples of fundamental studies to obtain a better understanding of the chemistry involved in fluid degradation are reviewed. Alternatives to high temperature fluid development are described. The importance of continuing work on improving current high temperature lubricant candidates and encouraging development of new and improved fluid base stocks are discussed.

  17. Fundamental considerations for future solid lubricants

    NASA Technical Reports Server (NTRS)

    Johnson, R. L.; Sliney, H. E.

    1969-01-01

    Properties important to the performance of solid lubricants are discussed. Those properties include shear characteristics, coherence between particles, resistance to cold flow, adherence to the substrate, applicable chemical thermodynamics and kinetics of materials and environments, polymorphism, and rheology. The following generalizations are made: (1) chemical thermodynamics and kinetics are powerful tools for use in determining the useful environments and methods of application for solid film lubricants; (2) the primary requirement for a solid lubricant is low shear strength; (3) the rheology of solid film constituents and formulations is likely to be of vital importance to performance and life; and (4) adherence and mobility of surface films is another primary requirement for long lived solid lubricants.

  18. Dry lubricant films for aluminum forming.

    SciTech Connect

    Wei, J.; Erdemir, A.; Fenske, G. R.

    1999-03-30

    During metal forming process, lubricants are crucial to prevent direct contact, adhesion, transfer and scuffing of workpiece materials and tools. Boric acid films can be firmly adhered to the clean aluminum surfaces by spraying their methanol solutions and provide extremely low friction coefficient (about 0.04). The cohesion strengths of the bonded films vary with the types of aluminum alloys (6061, 6111 and 5754). The sheet metal forming tests indicate that boric acid films and the combined films of boric acid and mineral oil can create larger strains than the commercial liquid and solid lubricants, showing that they possess excellent lubricities for aluminum forming. SEM analyses indicate that boric acid dry films separate the workpiece and die materials, and prevent their direct contact and preserve their surface qualities. Since boric acid is non-toxic and easily removed by water, it can be expected that boric acid films are environmentally friendly, cost effective and very efficient lubricants for sheet aluminum cold forming.

  19. Lubrication and cooling for high speed gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.

    1985-01-01

    The problems and failures occurring with the operation of high speed gears are discussed. The gearing losses associated with high speed gearing such as tooth mesh friction, bearing friction, churning, and windage are discussed with various ways shown to help reduce these losses and thereby improve efficiency. Several different methods of oil jet lubrication for high speed gearing are given such as into mesh, out of mesh, and radial jet lubrication. The experiments and analytical results for the various methods of oil jet lubrication are shown with the strengths and weaknesses of each method discussed. The analytical and experimental results of gear lubrication and cooling at various test conditions are presented. These results show the very definite need of improved methods of gear cooling at high speed and high load conditions.

  20. Potential of vegetable oils for lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetable oils offer significant advantages in terms of resource renewability, biodegradability, and comparable performance properties to petroleum-based products. The petroleum-based lubricants render unfavorable impact on the environment. With the growing environmental concerns, seed oils are find...

  1. Overview of liquid lubricants for advanced aircraft

    NASA Technical Reports Server (NTRS)

    Loomis, W. R.

    1982-01-01

    An overall status report on liquid lubricants for use in high-performance turbojet engines is presented. Emphasis is placed on the oxidation and thermal stability requirements imposed upon the lubrication system. A brief history is iven of the development of turbine engine lubricants which led to synthetic oils with their inherent modification advantages. The status and state of development of some nine candidate classes of fluids for use in advanced turbine engines are discussed. Published examples of fundamental studies to obtain a better understanding of the chemistry involved in fluid degradation are reviewed. Also, alternatives to high temperature fluid development are described. The importance of of continuing work on improving high temperature lubricant candidates and encouraging development of fluid base stocks is discussed.

  2. Tribometer for Lubrication Studies in Vacuum

    NASA Technical Reports Server (NTRS)

    Pepper, Stephen V.

    1998-01-01

    The NASA Lewis Research Center has developed a new way to evaluate the liquid lubricants used in ball bearings in space mechanisms. For this evaluation, a liquid lubricant is exercised in the rolling contact vacuum tribometer shown in the photo. This tribometer, which is essentially a thrust bearing with three balls and flat races, has contact stresses similar to those in a typical preloaded, angular contact ball bearing. The rotating top plate drives the balls in an outward-winding spiral orbit instead of a circular path. Upon contact with the "guide plate," the balls are forced back to their initial smaller orbit radius; they then repeat this spiral orbit thousands of times. The orbit rate of the balls is low enough, 2 to 5 rpm, to allow the system to operate in the boundary lubrication regime that is most stressful to the liquid lubricant. This system can determine the friction coefficient, lubricant lifetime, and species evolved from the liquid lubricant by tribodegradation. The lifetime of the lubricant charge is only few micrograms, which is "used up" by degradation during rolling. The friction increases when the lubricant is exhausted. The species evolved by the degrading lubricant are determined by a quadrupole residual gas analyzer that directly views the rotating elements. The flat races (plates) and 0.5-in.-diameter balls are of a configuration and size that permit easy post-test examination by optical and electron microscopy and the full suite of modern surface and thin-film chemical analytical techniques, including infrared and Raman microspectroscopy and x-ray photoelectron spectroscopy. In addition, the simple sphere-on-a-flat-plate geometry allows an easy analysis of the contact stresses at all parts of the ball orbit and an understanding of the frictional energy losses to the lubricant. The analysis showed that when the ball contacts the guide plate, gross sliding occurs between the ball and rotating upper plate as the ball forced back to a smaller

  3. New Lubricants Protect Machines and the Environment

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In 1994, NASA and Lockheed Martin Space Operations commissioned Sun Coast Chemicals of Daytona Inc to develop a new type of lubricant that would be safe for the environment and help "grease the wheels" of the shuttle-bearing launcher platform. Founded in 1989, Sun Coast Chemicals is known amongst the racing circuit for effective lubricants that help overcome engine and transmission problems related to heat and wear damage. In a matter of weeks, Sun Coast Chemical produced the biodegradable, high-performance X-1R Crawler Track Lube. In 1996, Sun Coast Chemical determined there was a market for this new development, and introduced three derivative products, Train Track Lubricant, Penetrating Spray Lubricant, and Biodegradable Hydraulic Fluid, and then quickly followed with a gun lubricant/cleaner and a fishing rod and reel lubricant. Just recently, Sun Coast introduced the X-1R Corporation, which folds the high-performance, environmentally safe benefits into a full line of standard automotive and specially formulated racing products. The entire X-1R automotive product line has stood up to rigorous testing by groups such as the American Society of Mechanical Engineers, the Swedish National Testing and Research Institute, the Department of Mechanical Engineering at Oakland University (Rochester, Michigan), and Morgan-McClure Motorsports (Abingdon, Virginia). The X-1R Corporation also markets "handy packs" for simple jobs around the house, consisting of a multi-purpose, multi-use lubricant and grease. In 2003, The X-1R Corporation teamed up with Philadelphia-based Penn Tackle Manufacturing Co., a leading manufacturer of fishing tackle since 1932, to jointly develop and market a line of advanced lubrication products for saltwater and freshwater anglers

  4. Advanced lubrication systems and materials. Final report

    SciTech Connect

    Hsu, S.

    1998-05-07

    This report described the work conducted at the National Institute of Standards and Technology under an interagency agreement signed in September 1992 between DOE and NIST for 5 years. The interagency agreement envisions continual funding from DOE to support the development of fuel efficient, low emission engine technologies in terms of lubrication, friction, and wear control encountered in the development of advanced transportation technologies. However, in 1994, the DOE office of transportation technologies was reorganized and the tribology program was dissolved. The work at NIST therefore continued at a low level without further funding from DOE. The work continued to support transportation technologies in the development of fuel efficient, low emission engine development. Under this program, significant progress has been made in advancing the state of the art of lubrication technology for advanced engine research and development. Some of the highlights are: (1) developed an advanced high temperature liquid lubricant capable of sustaining high temperatures in a prototype heat engine; (2) developed a novel liquid lubricant which potentially could lower the emission of heavy duty diesel engines; (3) developed lubricant chemistries for ceramics used in the heat engines; (4) developed application maps for ceramic lubricant chemistry combinations for design purpose; and (5) developed novel test methods to screen lubricant chemistries for automotive air-conditioning compressors lubricated by R-134a (Freon substitute). Most of these findings have been reported to the DOE program office through Argonne National Laboratory who manages the overall program. A list of those reports and a copy of the report submitted to the Argonne National Laboratory is attached in Appendix A. Additional reports have also been submitted separately to DOE program managers. These are attached in Appendix B.

  5. Polymer Lubricants For Use In Vacuum

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1989-01-01

    Report describes tests of lubricating properties of 10 polymer-based materials - in particular, polyimides - in vacuum. Commercially available materials, in forms of solid bodies and films on metals, were tested on pin-on-disk apparatus in vacuum. Best low-wear, low-friction material was 80 PMDA/20 BTDA solid-body polyimide. Friction and wear properties of most polyimides so good in vacuum that solid-lubricant additives not necessary.

  6. Anti-friction additives for lubricating oils

    SciTech Connect

    Karol, T.J.; Magaha, H.S.; Schlicht, R.C.

    1987-03-03

    A lubricating oil composition is described comprising (i) a major portion of lubricant oil; and (ii) from about 0.05 to about 10.0 wt.% of, as an additive, a product prepared by reacting a natural oil selected from the group consisting of coconut, babassu, palm, palm kernel, olive, castor, peanut, beef tallow and lard, with a (C/sub 2/-C/sub 10/) hydroxy acid and a polyamine.

  7. Materials as additives for advanced lubrication

    DOEpatents

    Pol, Vilas G.; Thackeray, Michael M.; Mistry, Kuldeep; Erdemir, Ali

    2016-09-13

    This invention relates to carbon-based materials as anti-friction and anti-wear additives for advanced lubrication purposes. The materials comprise carbon nanotubes suspended in a liquid hydrocarbon carrier. Optionally, the compositions further comprise a surfactant (e.g., to aid in dispersion of the carbon particles). Specifically, the novel lubricants have the ability to significantly lower friction and wear, which translates into improved fuel economies and longer durability of mechanical devices and engines.

  8. Tribology experiment. [journal bearings and liquid lubricants

    NASA Technical Reports Server (NTRS)

    Wall, W. A.

    1981-01-01

    A two-dimensional concept for Spacelab rack 7 was developed to study the interaction of liquid lubricants and surfaces under static and dynamic conditions in a low-gravity environment fluid wetting and spreading experiments of a journal bearing experiments, and means to accurately measure and record the low-gravity environment during experimentation are planned. The wetting and spreading process of selected commercial lubricants on representative surface are to the observes in a near-zero gravity environment.

  9. Composite coating for low friction and wear applications and method thereof

    DOEpatents

    Besmann, T.M.; Blau, P.J.; Lee, W.Y.; Bae, Y.W.

    1998-01-20

    An article having a multiphase composite lubricant coating of a hard refractory matrix phase of titanium nitride dispersed with particles of a solid lubricating phase of molybdenum disulfide is prepared by heating the article to temperatures between 350 and 850 C in a reaction vessel at a reduced pressure and passing a gaseous mixture of Ti((CH{sub 3}){sub 2}N){sub 4}, MoF{sub 6}, H{sub 2}S and NH{sub 3} over the heated article forming a multiphase composite lubricant coating on the article. 1 fig.

  10. Composite coating for low friction and wear applications and method thereof

    DOEpatents

    Besmann, Theodore M.; Blau, Peter J.; Lee, Woo Y.; Bae, Yong W.

    1998-01-01

    An article having a multiphase composite lubricant coating of a hard refractory matrix phase of titanium nitride dispersed with particles of a solid lubricating phase of molybdenum disulfide is prepared by heating the article to temperatures between 350.degree. and 850.degree. C. in a reaction vessel at a reduced pressure and passing a gaseous mixture of Ti((CH.sub.3).sub.2 N).sub.4, MoF.sub.6, H.sub.2 S and NH.sub.3 over the heated article forming a multiphase composite lubricant coating on the article.

  11. Foaming characteristics of refigerant/lubricant mixtures

    SciTech Connect

    Goswami, D.Y.; Shah, D.O.; Jotshi, C.K.; Bhagwat, S.; Leung, M.; Gregory, A.

    1997-04-01

    The air-conditioning and refrigeration industry has moved to HFC refrigerants which have zero ozone depletion and low global warming potential due to regulations on CFC and HCFC refrigerants and concerns for the environment. The change in refrigerants has prompted the switch from mineral oil and alkylbenzene lubricants to polyolester-based lubricants. This change has also brought about a desire for lubricant, refrigerant and compressor manufacturers to understand the foaming properties of alternative refrigerant/ lubricant mixtures, as well as the mechanisms which affect these properties. The objectives of this investigation are to experimentally determine the foaming absorption and desorption rates of HFC and blended refrigerants in polyolester lubricant and to define the characteristics of the foam formed when the refrigerant leaves the refrigerant/ lubricant mixture after being exposed to a pressure drop. The refrigerants being examined include baseline refrigerants: CFC-12 (R-12) and HCFC-22 (R-22); alternative refrigerants: HFC-32 (R-32), R-125, R-134a, and R-143a; and blended refrigerants: R-404A, R-407C, and R-410A. The baseline refrigerants are tested with ISO 32 (Witco 3GS) and ISO 68 (4GS) mineral oils while the alternative and blended refrigerants are tested with two ISO 68 polyolesters (Witco SL68 and ICI RL68H).

  12. Lubricating system for thermal medium delivery parts in a gas turbine

    DOEpatents

    Mashey, Thomas Charles

    2002-01-01

    Cooling steam delivery tubes extend axially along the outer rim of a gas turbine rotor for supplying cooling steam to and returning spent cooling steam from the turbine buckets. Because of the high friction forces at the interface of the tubes and supporting elements due to rotor rotation, a low coefficient of friction coating is provided at the interface of the tubes and support elements. On each surface, a first coating of a cobalt-based alloy is sprayed onto the surface at high temperature. A portion of the first coating is machined off to provide a smooth, hard surface. A second ceramic-based solid film lubricant is sprayed onto the first coating. By reducing the resistance to axial displacement of the tubes relative to the supporting elements due to thermal expansion, the service life of the tubes is substantially extended.

  13. Based Adaptive Nanocomposite Coatings

    NASA Astrophysics Data System (ADS)

    Ramazani, M.; Ashrafizadeh, F.; Mozaffarinia, R.

    2014-08-01

    A promising Ni(Al)-Cr2O3-Ag-CNT-WS2 self-lubricating wear-resistant coating was deposited via atmospheric plasma spray of Ni(Al), nano Cr2O3, nano silver and nano WS2 powders, and CNTs. Feedstock powders with various compositions prepared by spray drying were plasma sprayed onto carbon steel substrates. The tribological properties of coatings were tested by a high temperature tribometer in a dry environment from room temperature to 400 °C, and in a natural humid environment at room temperature. It was found that all nanocomposite coatings have better frictional behavior compared with pure Ni(Al) and Ni(Al)-Cr2O3 coatings; the specimen containing aproximately 7 vol.% Ag, CNT, and WS2 had the best frictional performance. The average room temperature friction coefficient of this coating was 0.36 in humid atmosphere, 0.32 in dry atmosphere, and about 0.3 at high temperature.

  14. Intermetallic Nickel-Titanium Alloys for Oil-Lubricated Bearing Applications

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Pepper, S. V.; Noebe, R.; Hull, D. R.; Glennon, G.

    2009-01-01

    An intermetallic nickel-titanium alloy, NITINOL 60 (60NiTi), containing 60 wt% nickel and 40 wt% titanium, is shown to be a promising candidate material for oil-lubricated rolling and sliding contact applications such as bearings and gears. NiTi alloys are well known and normally exploited for their shape memory behavior. When properly processed, however, NITINOL 60 exhibits excellent dimensional stability and useful structural properties. Processed via high temperature, high-pressure powder metallurgy techniques or other means, NITINOL 60 offers a broad combination of physical properties that make it unique among bearing materials. NITINOL 60 is hard, electrically conductive, highly corrosion resistant, less dense than steel, readily machined prior to final heat treatment, nongalling and nonmagnetic. No other bearing alloy, metallic or ceramic encompasses all of these attributes. Further, NITINOL 60 has shown remarkable tribological performance when compared to other aerospace bearing alloys under oil-lubricated conditions. Spiral orbit tribometer (SOT) tests were conducted in vacuum using NITINOL 60 balls loaded between rotating 440C stainless steel disks, lubricated with synthetic hydrocarbon oil. Under conditions considered representative of precision bearings, the performance (life and friction) equaled or exceeded that observed with silicon nitride or titanium carbide coated 440C bearing balls. Based upon this preliminary data, it appears that NITINOL 60, despite its high titanium content, is a promising candidate alloy for advanced mechanical systems requiring superior and intrinsic corrosion resistance, electrical conductivity and nonmagnetic behavior under lubricated contacting conditions.

  15. Krytox Lubrication Tape Study. [fluorinated lubricating oil for video tape recorders

    NASA Technical Reports Server (NTRS)

    Lee, F.

    1978-01-01

    The use of Krytox, a fluorinated oil, as a tape surface lubricant was studied for a wideband video tape recorder. In spite of the 5 to 1 head wear reduction credited to the surface lubricant, the resultant head life fell short of the 1500 hour goal.

  16. 41 CFR 101-26.602-1 - Procurement of lubricating oils, greases, and gear lubricants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-26.602-1 Procurement of lubricating oils, greases, and gear lubricants. (a) The Defense Fuel Supply... submit requests to: Commander, Defense Fuel Supply Center, Attn: DFSC:PG, Cameron Station, Alexandria, VA 22314, on or before the requirement due dates specified in § 101-26.602-1(a). Submission of...

  17. Reduced Need of Lubricity Additives in Soybean Oil Blends Under Boundary Lubrication Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Converging prices of vegetable oils and petroleum, along with increased focus on renewable resources, gave more momentum to vegetable oil lubricants. Boundary lubrication properties of four Extreme Pressure (EP) additive blends in conventional Soy Bean Oil (SBO) and Paraffinic Mineral Oil (PMO) of ...

  18. Compatibility of lubricant additives with HFC refrigerants and synthetic lubricants. Final report, Part 1

    SciTech Connect

    Cavestri, R.C.

    1997-07-01

    Part one of this research provides manufacturers of components of air-conditioning and refrigeration equipment with a useful list of lubricant additives, sources, functional properties and chemical species. The list in part one is comprised of domestic lubricant additive suppliers and the results of a literature search that was specifically targeted for additives reported to be useful in polyolester chemistry.

  19. Evaluation of the lubrication mechanism at various rotation speeds and granule filling levels in a container mixer using a thermal effusivity sensor.

    PubMed

    Uchiyama, Jumpei; Aoki, Shigeru

    2015-01-01

    To research the detailed mechanism of the lubrication process using the thermal effusivity sensor, the relationships of the lubrication progress with the pattern of powder flow, the rotation speed and the filling level were investigated. The thermal effusivity profile was studied as a function of the number of rotations at various rotation speeds. It was observed that at lower rotation speeds, the profiles of the lubrication progress were almost the same, regardless of the rotation speed. In this region, the highest speed was defined as the critical rotation speed (CRS), which was found to be one of the important factors. The CRS had close relations with avalanche flow in the blender. The first and the second phases were observed in the lubrication process. The first phase was influenced by the CRS and the filling level in the blender. The second phase was influenced by the rotation speed. The mechanism of two-phase process was proposed as a macro progression of the dispersion of the lubricant (first phase) and micro progression of the coating of the powder particles with lubricant (second phase). The accurate monitoring by the thermal effusivity sensor was able to help a better understanding in the lubrication process.

  20. Evaluation of the lubrication mechanism at various rotation speeds and granule filling levels in a container mixer using a thermal effusivity sensor.

    PubMed

    Uchiyama, Jumpei; Aoki, Shigeru

    2015-01-01

    To research the detailed mechanism of the lubrication process using the thermal effusivity sensor, the relationships of the lubrication progress with the pattern of powder flow, the rotation speed and the filling level were investigated. The thermal effusivity profile was studied as a function of the number of rotations at various rotation speeds. It was observed that at lower rotation speeds, the profiles of the lubrication progress were almost the same, regardless of the rotation speed. In this region, the highest speed was defined as the critical rotation speed (CRS), which was found to be one of the important factors. The CRS had close relations with avalanche flow in the blender. The first and the second phases were observed in the lubrication process. The first phase was influenced by the CRS and the filling level in the blender. The second phase was influenced by the rotation speed. The mechanism of two-phase process was proposed as a macro progression of the dispersion of the lubricant (first phase) and micro progression of the coating of the powder particles with lubricant (second phase). The accurate monitoring by the thermal effusivity sensor was able to help a better understanding in the lubrication process. PMID:25000482

  1. Surface roughness effects with solid lubricants dispersed in mineral oils

    NASA Technical Reports Server (NTRS)

    Cusano, C.; Goglia, P. R.; Sliney, H. E.

    1983-01-01

    The lubricating effectiveness of solid-lubricant dispersions are investigated in both point and line contacts using surfaces with both random and directional roughness characteristics. Friction and wear data obtained at relatively low speeds and at room temperature, indicate that the existence of solid lubricants such as graphite, MoS2, and PTFE in a plain mineral oil generally will not improve the effectiveness of the oil as a lubricant for such surfaces. Under boundary lubrication conditions, the friction force, as a function of time, initially depends upon the directional roughness properties of the contacting surfaces irrespective of whether the base oil or dispersions are used as lubricants.

  2. Lubrication study for Single Point Incremental Forming of Copper

    NASA Astrophysics Data System (ADS)

    Jawale, Kishore; Ferreira Duarte, José; Reis, Ana; Silva, M. B.

    2016-08-01

    In conventional machining and sheet metal forming processes, in general, lubrication assists to increase the quality of the final product. Similarly it is observed that there is a positive effect of the use of lubrication in Single point incremental forming, namely in the surface roughness. This study is focused on the investigation of the most appropriate lubricant for incremental forming of copper sheet. The study involves the selection of the best lubricant from a range of several lubricants that provides the best surface finishing. The influence of the lubrication on other parameters such as the maximum forming angle, the fracture strains and the deformed profile are also studied for Copper.

  3. Influence of liquid lubricant properties on their performance.

    NASA Technical Reports Server (NTRS)

    Wedeven, V.

    1972-01-01

    The influence of lubricant properties on performance is considered in connection with various mechanisms of lubrication. The effects of temperature and pressure on viscosity, which is important in hydrodynamic and elastohydrodynamic lubrication, is presented using a correlation postulated by Roelands. Under elastohydrodynamic conditions it is important to distinguish between the influence of lubricant properties within the inlet region and the Hertz region since each performs different functions. The role of lubricant transport properties such as surface tension is considered in connection with lubricant starvation.

  4. Mechanisms of lubrication and wear of a bonded solid lubricant film

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1980-01-01

    To obtain a better understanding of how bonded solid lubricant films lubricate and wear (in general), the tribological properties of polyimide-bonded graphite fluoride films were studied (in specific). A pin-on-disk type of testing apparatus was used; but in addition to sliding a hemispherically tipped rider, a rider with a 0.95 mm diameter flat area was slid against the film. This was done so that a lower, less variable contact stress could be achieved. Two stages of lubrication occurred. In the first, the film supported the load. The lubricating mechanism consisted of the shear of a thin surface layer (of the film) between the rider and the bulk of the film. The second occurred after the bonded film had worn to the substrate, and consisted of the shear of very thin lubricant films between the rider and flat plateaus generated on the metallic substrate asperities. The film wear mechanism was strongly dependent on contact stress.

  5. Experimental investigations of elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1983-01-01

    Various experimental studies of elastohydrodynamic lubrication have been reviewed. The various types of machines used in these investigations, such as the disc, two and four ball, crossed-cylinders, and crossed-axes rolling disc machine, are described. The measurement of the most important parameters, such as film shape, film thickness, pressure, temperature, and traction, is considered. Determination of the film thickness is generally the most important of these effects since it dictates the extent to which the asperities on opposing surfaces can come into contact and thus has a direct bearing on wear and fatigue failure of the contacting surfaces. Several different techniques for measuring film thickness have been described, including electrical resistance, capacitance, X-ray, optical interferometry, laser beam diffraction, strain gage, and spring dynamometer methods. An attempt has been made to describe the basic concepts and limitations of each of these techniques. These various methods have been used by individual researchers, but there is no universally acceptable technique for measuring elastohydrodynamic film thickness. Capacitance methods have provided most of the reliable data for nominal line or rectangular conjunctions, but optical interferometry has proved to be the most effective procedure for elliptical contacts. Optical interferometry has the great advantage that it reveals not only the film thickness, but also details of the film shape over the complete area of the conjunction.

  6. Tribology and Microstructure of PS212 with a Cr2O3 Seal Coat

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Benoy, Patricia A.; Korenyi-Both, Andras; Dellacorte, Christopher

    1994-01-01

    PS212 is a plasma sprayed metal bonding chrome carbide coating with solid lubricant additives which has lubricating properties at temperatures up to about 900 deg C. The coating is diamond ground to achieve an acceptable tribological surface. But, as with many plasma spray coatings, PS212 is not fully-dense. In this study, a chromium oxide base seal coating is used in an attempt to seal any porosity that is open to the surface of the PS212 coating, and to study the effect of the sealant on the tribological properties of PS212. The results indicate that the seal coating reduces friction and wear when it is applied and then diamond ground leaving a thin layer of seal coating which fills in the surface pits of the PS212 coating.

  7. Transparency and damage tolerance of patternable omniphobic lubricated surfaces based on inverse colloidal monolayers

    NASA Astrophysics Data System (ADS)

    Vogel, Nicolas; Belisle, Rebecca A.; Hatton, Benjamin; Wong, Tak-Sing; Aizenberg, Joanna

    2013-07-01

    A transparent coating that repels a wide variety of liquids, prevents staining, is capable of self-repair and is robust towards mechanical damage can have a broad technological impact, from solar cell coatings to self-cleaning optical devices. Here we employ colloidal templating to design transparent, nanoporous surface structures. A lubricant can be firmly locked into the structures and, owing to its fluidic nature, forms a defect-free, self-healing interface that eliminates the pinning of a second liquid applied to its surface, leading to efficient liquid repellency, prevention of adsorption of liquid-borne contaminants, and reduction of ice adhesion strength. We further show how this method can be applied to locally pattern the repellent character of the substrate, thus opening opportunities to spatially confine any simple or complex fluids. The coating is highly defect-tolerant due to its interconnected, honeycomb wall structure, and repellency prevails after the application of strong shear forces and mechanical damage. The regularity of the coating allows us to understand and predict the stability or failure of repellency as a function of lubricant layer thickness and defect distribution based on a simple geometric model.

  8. Transparency and damage tolerance of patternable omniphobic lubricated surfaces based on inverse colloidal monolayers

    SciTech Connect

    Vogel, Nicolas; Belisle, Rebecca A.; Hatton, Benjamin; Wong, Tak-Sing; Aizenberg, Joanna

    2013-07-31

    A transparent coating that repels a wide variety of liquids, prevents staining, is capable of self-repair and is robust towards mechanical damage can have a broad technological impact, from solar cell coatings to self-cleaning optical devices. Here we employ colloidal templating to design transparent, nanoporous surface structures. A lubricant can be firmly locked into the structures and, owing to its fluidic nature, forms a defect-free, self-healing interface that eliminates the pinning of a second liquid applied to its surface, leading to efficient liquid repellency, prevention of adsorption of liquid-borne contaminants, and reduction of ice adhesion strength. We further show how this method can be applied to locally pattern the repellent character of the substrate, thus opening opportunities to spatially confine any simple or complex fluids. The coating is highly defect-tolerant due to its interconnected, honeycomb wall structure, and repellency prevails after the application of strong shear forces and mechanical damage. The regularity of the coating allows us to understand and predict the stability or failure of repellency as a function of lubricant layer thickness and defect distribution based on a simple geometric model.

  9. Transparency and damage tolerance of patternable omniphobic lubricated surfaces based on inverse colloidal monolayers

    DOE PAGESBeta

    Vogel, Nicolas; Belisle, Rebecca A.; Hatton, Benjamin; Wong, Tak-Sing; Aizenberg, Joanna

    2013-07-31

    A transparent coating that repels a wide variety of liquids, prevents staining, is capable of self-repair and is robust towards mechanical damage can have a broad technological impact, from solar cell coatings to self-cleaning optical devices. Here we employ colloidal templating to design transparent, nanoporous surface structures. A lubricant can be firmly locked into the structures and, owing to its fluidic nature, forms a defect-free, self-healing interface that eliminates the pinning of a second liquid applied to its surface, leading to efficient liquid repellency, prevention of adsorption of liquid-borne contaminants, and reduction of ice adhesion strength. We further show howmore » this method can be applied to locally pattern the repellent character of the substrate, thus opening opportunities to spatially confine any simple or complex fluids. The coating is highly defect-tolerant due to its interconnected, honeycomb wall structure, and repellency prevails after the application of strong shear forces and mechanical damage. The regularity of the coating allows us to understand and predict the stability or failure of repellency as a function of lubricant layer thickness and defect distribution based on a simple geometric model.« less

  10. Lubrication regimes in lumbar total disc arthroplasty.

    PubMed

    Shaheen, A; Shepherd, D E T

    2007-08-01

    A number of total disc arthroplasty devices have been developed. Some concern has been expressed that wear may be a potential failure mode for these devices, as has been seen with hip arthroplasty. The aim of this paper was to investigate the lubrication regimes that occur in lumbar total disc arthroplasty devices. The disc arthroplasty was modelled as a ball-and-socket joint. Elastohydrodynamic lubrication theory was used to calculate the minimum film thickness of the fluid between the bearing surfaces. The lubrication regime was then determined for different material combinations, size of implant, and trunk velocity. Disc arthroplasties with a metal-polymer or metal-metal material combination operate with a boundary lubrication regime. A ceramic-ceramic material combination has the potential to operate with fluid-film lubrication. Disc arthroplasties with a metal-polymer or metal-metal material combination are likely to generate wear debris. In future, it is worth considering a ceramic-ceramic material combination as this is likely to reduce wear.

  11. Solid Lubrication Fundamentals and Applications. Chapter 6

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2000-01-01

    This chapter focuses attention on the friction and wear properties of selected solid lubricating films to aid users in choosing the best lubricant, deposition conditions, and operational variables. For simplicity, discussion of the tribological properties of concern is separated into two parts. The first part of the chapter discusses the different solid lubricating films selected for study including commercially developed solid film lubricants: (1) bonded molybdenum disulfide (MoS2), (2) magnetron-sputtered MoS2, (3) ion-plated silver, (4) ion-plated lead, (5) magnetron-sputtered diamondlike carbon (MS DLC), and (6) plasma-assisted, chemical-vapor-deposited diamondlike carbon (PACVD DEC) films. Marked differences in the friction and wear properties of the different films resulted from the different environmental conditions (ultrahigh vacuum, humid air, and dry nitrogen) and the solid film lubricant materials. The second part of the chapter discusses the physical and chemical characteristics, friction behavior, and endurance life of the magnetron-sputtered MoS2 films. The role of interface species and the effects of applied load, film thickness, oxygen pressure, environment, and temperature on the friction and wear properties are considered.

  12. Processing and Formulation of Lithium Lubricating Greases

    NASA Astrophysics Data System (ADS)

    Delgado, M. A.; Franco, J. M.; Valencia, C.; Moreno, G.; Gallegos, C.

    2006-05-01

    The effects that soap concentration, base oil viscosity and additives exert on the rheology of lubricating greases have been studied. Also, changes in both microstructure and rheology of lithium lubricating greases during their manufacturing process have been evaluated. With this aim, different lithium lubricating grease formulations were manufactured by modifying the concentration of lithium 12-hydroxystearate, base oil viscosity and processing conditions or using different polymeric additives. The manufacturing process was followed through the mixing rheometry technique by measuring the evolution of torque with processing time, and samples of incipient and finished greases were taken from the stirred tank at different processing times. Rheological (small-amplitude oscillatory shear (SAOS)) and scanning electronic microscopy (SEM) observations were carried out on each sample. The experimental results obtained demonstrate that the values of the linear viscoelasticity functions and the mechanical behaviour of lubricating grease strongly depend on the processing variables and grease composition. Also, it has been found that the structural skeleton (size and shape of the disperse phase particles) is highly influenced by the base oil viscosity. These results have been explained taking into account the balance between the solvency of the thickener in the base oil and the level of entanglements formed by soap fibres, which influence the lubricating grease network.

  13. Effect of fullerene containing lubricants on wear resistance of machine components in boundary lubrication

    NASA Astrophysics Data System (ADS)

    Titov, Andriy

    Fullerenes, a new form of carbon nanomaterials, possess unique physical and mechanical properties that make their use as additives to liquid lubricants potentially beneficial. The goal of this study was to investigate the effect of fullerene containing lubricants on wear resistance of steel-bronze couples operating under boundary lubrication conditions. A mathematical model of deformed asperity contact was built to calculate real contact area and real contact pressure. Computer controlled wear friction testing methodology and equipment were designed, developed and implemented for obtaining reliable and objective experimental data. In addition, optical and scanning electron microscopy and standard surface texture analysis were employed. Heavy duty motor oil SAE 10 was modified by admixing fullerenes C60, a fullerene mixture of C60 and C70, fullerene containing soot, and graphite powder. The experiments showed that all of the selected fullerene additives dissolved in liquid lubricants reduce wear of the tested materials. In addition, it was found that despite improvements in wear resistance, the selected modified lubricants did not significantly change friction characteristics. Improvement of wear resistance of contact surfaces operating with fullerene modified lubricants can be explained by the presence of fullerenes in real contact while the liquid lubricant is squeezed out. Fullerenes are considered to function as minute hard particles that do not break down under applied normal force, and tend to separate direct contact of functional surfaces of selected materials.

  14. Mechanics of a gaseous film barrier to lubricant wetting of elastohydrodynamically lubricated conjunctions

    NASA Technical Reports Server (NTRS)

    Prahl, J. M.; Hamrock, B. J.

    1985-01-01

    Two analytical models, one based on simple hydrodynamic lubrication and the other on soft elastohydrodynamic lubrication, are presented and compared to delineate the dominant physical parameters that govern the mechanics of a gaseous film between a small droplet of lubricant and the outer race of a ball bearing. Both models are based on the balance of gravity forces, air drag forces, and air film lubrication forces and incorporate a drag coefficient C sub D and a lubrication coefficient C sub L to be determined from experiment. The soft elastohydrodynamic lubrication (EHL) model considers the effects of droplet deformation and solid-surface geometry; the simpler hydrodynamic lubrication (HL) model assumes that the droplet remains essentially spherical. The droplet's angular position depended primarily on the ratio of gas inertia to droplet gravity forces and on the gas Reynolds number and weakly on the ratio of droplet gravity forces to surface tension forces (Bond number) and geometric ratios for the soft EHL. An experimental configuration in which an oil droplet is supported by an air film on the rotating outer race of a ball bearing within a pressure-controlled chamber produced measurements of droplet angular position as a function of outer-race velocity droplet size and type, and chamber pressure.

  15. Effects of nanoscale surface texture and lubricant molecular structure on boundary lubrication in liquid.

    PubMed

    Al-Azizi, Ala' A; Eryilmaz, Osman; Erdemir, Ali; Kim, Seong H

    2013-11-01

    Nanoconfinement effects of boundary lubricants can significantly affect the friction behavior of textured solid interfaces. These effects were studied with nanotextured diamond-like carbon (DLC) surfaces using a reciprocating ball-on-flat tribometer in liquid lubricants with different molecular structures: n-hexadecane and n-pentanol for linear molecular structure and poly(α-olefin) and heptamethylnonane for branched molecular structure. It is well-known that liquid lubricants with linear molecular structures can readily form a long-range ordered structure upon nanoconfinement between flat solid surfaces. This long-range ordering, often called solidification, causes high friction in the boundary lubrication regime. When the solid surface deforms elastically due to the contact pressure and this deformation depth is larger than the surface roughness, even rough surfaces can exhibit the nanoconfinement effects. However, the liquid entrapped in the depressed region of the nanotextured surface would not solidify, which effectively reduces the solidified lubricant area in the contact region and decreases friction. When liquid lubricants are branched, the nanoconfinement-induced solidification does not occur because the molecular structure is not suitable for the long-range ordering. Surface texture, therefore, has an insignificant effect on the boundary lubrication of branched molecules.

  16. Effects of nanoscale surface texture and lubricant molecular structure on boundary lubrication in liquid.

    PubMed

    Al-Azizi, Ala' A; Eryilmaz, Osman; Erdemir, Ali; Kim, Seong H

    2013-11-01

    Nanoconfinement effects of boundary lubricants can significantly affect the friction behavior of textured solid interfaces. These effects were studied with nanotextured diamond-like carbon (DLC) surfaces using a reciprocating ball-on-flat tribometer in liquid lubricants with different molecular structures: n-hexadecane and n-pentanol for linear molecular structure and poly(α-olefin) and heptamethylnonane for branched molecular structure. It is well-known that liquid lubricants with linear molecular structures can readily form a long-range ordered structure upon nanoconfinement between flat solid surfaces. This long-range ordering, often called solidification, causes high friction in the boundary lubrication regime. When the solid surface deforms elastically due to the contact pressure and this deformation depth is larger than the surface roughness, even rough surfaces can exhibit the nanoconfinement effects. However, the liquid entrapped in the depressed region of the nanotextured surface would not solidify, which effectively reduces the solidified lubricant area in the contact region and decreases friction. When liquid lubricants are branched, the nanoconfinement-induced solidification does not occur because the molecular structure is not suitable for the long-range ordering. Surface texture, therefore, has an insignificant effect on the boundary lubrication of branched molecules. PMID:24156745

  17. Candidate Coatings and Dry Traction Drives for Planetary Vehicles

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert; Oswald, Fred B.

    2002-01-01

    Robert Fusaro and Fred Oswald of the Mechanical Components Branch discussed 'Candidate Coatings and Dry Traction Drives for Planetary Vehicles'. Vehicles to be designed for exploration of planets and moons of the solar system will require reliable mechanical drives to operate efficiently. Long-term operation of these drives will be challenging because of extreme operating conditions. These extreme conditions include: very high and/or very cold temperatures, wide temperature ranges, dust, vacuum or low-pressure atmospheres, and corrosive environments. Most drives used on Earth involve oil-lubricated gears. However, due to the extreme conditions on planetary surfaces, it may not be advisable or even possible to use oil lubrication. Unfortunately, solid lubricants do not work well when applied to gears because of the high contact stress conditions and large sliding motion between the teeth, which cause wear and limit life. We believe traction drives will provide an attractive alternative to gear drives. Traction drives are composed of rollers that provide geometry more conducive to solid lubrication. Minimal slip occurs in this contact geometry and thus there is very low wear to the solid lubricant. The challenge for these solid-lubricated drives is finding materials or coatings that provide the required long-life while also providing high traction. We seek materials that provide low wear with high friction.

  18. Practical Applications and Uses of Solid Lubricant Films

    NASA Technical Reports Server (NTRS)

    Stupp, B. C.

    1984-01-01

    Practical applications are illustrated with discussions covering the reasons for use of solid lubricants, required performance, lubricant selection, and results obtained for the various examples shown. The applications described cover a broad range of solid lubricants. Included are soft lamellar compounds, organic polymers, soft elemental metals, oxides and compounds for high temperature use. The illustrations selected cover a broad range of lubricant application techniques delineating the reasons for the different processing procedures which include bonded films, plasma spraying, sputtering, ion plating and electrodeposition.

  19. Dynamic friction and wear of a solid film lubricant during radiation exposure in a nuclear reactor

    NASA Technical Reports Server (NTRS)

    Jacobson, T. P.

    1972-01-01

    The effect of nuclear reactor radiation on the performance of a solid film lubricant was studied. The film consisted of molybdenum disulfide and graphite in a sodium silicate binder. Radiation levels of fast neutrons (E or = 1 MeV) were fluxed up to 3.5 times 10 to the 12th power n/sq cm-sec (intensity) and fluences up to 2 times 10 to the 18th power n/sq cm (total exposure). Coating wear lives were much shorter and friction coefficients higher in a high flux region of the reactor than in a low flux region. The amount of total exposure did not affect lubrication behavior as severely as the radiation intensity during sliding.

  20. Characterization of full-length recombinant human Proteoglycan 4 as an ocular surface boundary lubricant.

    PubMed

    Samsom, Michael L; Morrison, Sheila; Masala, Nemanja; Sullivan, Benjamin D; Sullivan, David A; Sheardown, Heather; Schmidt, Tannin A

    2014-10-01

    Proteoglycan 4 (PRG4, or lubricin) is a lubricating mucin-like glycoprotein recently discovered at the ocular surface, where it functions as a boundary lubricant and appears to play a protective role. Recent technological advances have enabled abundant expression of full-length recombinant human PRG4 (rhPRG4). The objectives of this study were to 1) biochemically characterize the gross structure and glycosylations of full-length rhPRG4, and 2) assess the ocular surface boundary lubricating ability of rhPRG4 at both human cornea-eyelid and human cornea-polydimethylsiloxane (PDMS) biointerfaces. rhPRG4 expressed by a Chinese hamster ovary cell line was characterized and compared to native bovine PRG4 by SDS-PAGE western blotting, and protein identity was assessed by tandem mass spectrometry (MS/MS). Human corneas were articulated against PDMS or human eyelids, at effective sliding velocities of 0.3-30 mm/s under physiological loads of ∼15 kPa, to assess and compare the ocular lubricating ability of rhPRG4 to PRG4. Samples were tested serially in PRG4, rhPRG4 (both 300 μg/ml), then saline. Western blotting indicated that rhPRG4 had immunoreactivity at the appropriate apparent molecular weight, and possessed O-linked glycosylation consistent with that of PRG4. rhPRG4 protein identity was confirmed by MS/MS. Both PRG4 and rhPRG4 significantly, and similarly, reduced friction compared to saline at both human cornea - PDMS and human cornea-eyelid biointerfaces. In conclusion, the rhPRG4 studied here demonstrated appropriate higher order structure, O-linked glycosylations, and ocular surface boundary lubricating. Purified rhPRG4 may have clinical utility as a topical treatment of dry eye disease or contact lens biomaterial coating to promote more comfortable wear. PMID:24997456

  1. Rheological effects on friction in elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Trachman, E. G.; Cheng, H. S.

    1973-01-01

    An analytical and experimental investigation is presented of the friction in a rolling and sliding elastohydrodynamic lubricated contact. The rheological behavior of the lubricant is described in terms of two viscoelastic models. These models represent the separate effects of non-Newtonian behavior and the transient response of the fluid. A unified description of the non-Newtonian shear rate dependence of the viscosity is presented as a new hyperbolic liquid model. The transient response of viscosity, following the rapid pressure rise encountered in the contact, is described by a compressional viscoelastic model of the volume response of a liquid to an applied pressure step. The resulting momentum and energy equations are solved by an iterative numerical technique, and a friction coefficient is calculated. The experimental study was performed, with two synthetic paraffinic lubricants, to verify the friction predictions of the analysis. The values of friction coefficient from theory and experiment are in close agreement.

  2. Compatibility of refrigerants and lubricants with elastomers

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.

    1993-01-01

    The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on availability of additional R-32. Swell behavior in the fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  3. Sputtering technology in solid film lubrication

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1978-01-01

    Potential and present sputtering technology is discussed as it applies to the deposition of solid film lubricants particularly MoS2, WS2, and PTFE. Since the sputtered films are very thin, the selection of the sputtering parameters and substrate condition is very critical as reflected by the lubricating properties. It was shown with sputtered MoS2 films that the lubricating characteristics are directly affected by the selected sputtering parameters (power density, pressure, sputter etching, dc-biasing, etc.) and the substrate temperature, chemistry, topography and the environmental conditions during the friction tests. Electron microscopy and other surface sensitive analytical techniques illustrate the resulting changes in sputtered MoS2 film morphology and chemistry which directly influence the film adherence and frictional properties.

  4. NASA Lessons Learned from Space Lubricated Mechanisms

    NASA Technical Reports Server (NTRS)

    Predmore, Roamer E.

    2000-01-01

    This document reviews the lessons learned from short-life and long life lubricated space mechanisms. A short-life lubricated mechanisms complete their life test qualification requirements after a few cycles. The mechanisms include the hinges, motors and bearings for deployment, release mechanisms, latches, release springs and support shops. Performance testing can be difficult and expensive but must be accomplished. A long-life lubricated mechanisms requires up to 5 years of life testing, or 10 to 100 years of successful flight. The long-life mechanisms include reaction wheels, momentum wheels, antenna gimbals, solar array drives, gyros and despin mechanisms. Several instances of how a mechanisms failed either in test, or in space use, and the lessons learned from these failures are reviewed. The effect of the movement away from CFC-113 cleaning solvent to ODC (Ozone-Depleting Chemical) -free is reviewed, and some of the alternatives are discussed.

  5. Miscibility of lubricants with refrigerants, Phase 1

    SciTech Connect

    Pate, M.B.; Zoz, S.C.; Berkenbosch, L.J. . Dept. of Agricultural Engineering)

    1992-10-01

    Miscibility data have been obtained for a variety of non-CFC refrigerants and their potential lubricants. Ten different refrigerants and seven different lubricants were investigated. Experiments are being performed in two phases: Phase I, reported herein, focuses on performing screening tests for miscibility and Phase II consists of developing miscibility plots. The miscibility tests are being performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The bath temperature can be precisely controlled over a temperature range of -50 C to 90C(-58 F to 194 F). The test cells are constructed to allow for complete visibility of lubricant-refrigerant mixtures under all test conditions.

  6. Used lubricating oil recycling using hydrocarbon solvents.

    PubMed

    Hamad, Ahmad; Al-Zubaidy, Essam; Fayed, Muhammad E

    2005-01-01

    A solvent extraction process using new hydrocarbon solvents was employed to treat used lubricant oil. The solvents used were liquefied petroleum gas (LPG) condensate and stabilized condensate. A demulsifier was used to enhance the treatment process. The extraction process using stabilized condensate demonstrated characteristics that make it competitive with existing used oil treatment technologies. The process is able to reduce the asphaltene content of the treated lubricating oil to 0.106% (w/w), the ash content to 0.108%, and the carbon residue to 0.315% with very low levels of contaminant metals. The overall yield of oil is 79%. The treated used oil can be recycled as base lubricating oil. The major disadvantage of this work is the high temperature of solvent recovery. Experimental work and results are presented in detail. PMID:15627468

  7. Compatibility of refrigerants and lubricants with elastomers

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.

    1992-10-01

    Information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on the availability of additional quantities of R-32. Swell behavior in the fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  8. Additives for high-temperature liquid lubricants

    NASA Technical Reports Server (NTRS)

    Lawton, Emil A.; Yavrouian, Andre H.; Repar, John

    1988-01-01

    A preliminary research program was conducted to demonstrate a new concept for additives to liquid lubricants. It was demonstrated that suspensions of o-phthalonitrile and a substituted 1,2-maleonitrile in mineral oil and dilute solutions of o-phthalonitrile and tetrafluoro-o-phthalonitrile extended the lifetime of bearings under boundary lubricating conditions. The solutions exhibited coefficients of friction under high loads of 0.02-0.03. These results were consistent with the hypothesis that these compounds react with the hot metal surface to form a planar lubricating film by means of a metal or metal oxide template reaction. Also, the adherence was very strong due to the chelating action of the planar macrocycles postulated to form under the experimental conditions.

  9. Wormgear geometry adopted for implementing hydrostatic lubrication and formulation of the lubrication problem

    NASA Technical Reports Server (NTRS)

    Sun, D. C.; Yuan, Qin

    1995-01-01

    The geometrical parameters for a wormgear intended to be used as the transmission in advanced helicopters are finalized. The resulting contact pattern of the meshing tooth surfaces is suitable for the implementation of hydrostatic lubrication Fluid film lubrication of the contact is formulated considering external pressurization as well as hydrodynamic wedge and squeeze actions. The lubrication analysis is aimed at obtaining the oil supply pressure needed to separate the worm and gear surfaces by a prescribed minimum film thickness. The procedure of solving the mathematical problem is outlined.

  10. Materials compatibility and lubricants research on CFC-refrigerant substitute: Miscibility of lubricants with refrigerants

    SciTech Connect

    Pate, M.B.; Zoz, S.; Berkenbosch, L. . Dept. of Mechanical Engineering)

    1992-04-01

    During this reporting period, modifications were made to the experimental apparatus in preparation for performing the experiments required in this project. In addition, new procedures for charging the lubricant and refrigerant into the cells for high temperature tests have been adopted. All of the refrigerants (10 different types) and lubricants (seven different types) have been ordered from the manufacturers. To date, the data obtained includes that for R-134a and four lubricants, namely, two esters and two polypropylene glycols (PAGs). Methods for quantifying immiscibility based on observation by different lab workers have been developed.

  11. FY2013 Progress Report for Fuel & Lubricant Technologies

    SciTech Connect

    none,

    2014-02-01

    Annual progress report for Fuel & Lubricant Technologies. The Fuel & Lubricant Technologies Program supports fuels and lubricants research and development (R&D) to provide vehicle manufacturers and users with cost-competitive options that enable high fuel economy with low emissions, and contribute to petroleum displacement.

  12. 7 CFR 2902.43 - Chain and cable lubricants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Chain and cable lubricants. 2902.43 Section 2902.43... Items § 2902.43 Chain and cable lubricants. (a) Definition. Products designed to provide lubrication in such applications as bar and roller chains, sprockets, and wire ropes and cables. Products may...

  13. [Identification of automotive lubricants and other heavy oils by isotachophoresis].

    PubMed

    Ishizawa, F; Misawa, S

    1989-06-01

    Automotive lubricants were analysed by isotachophoresis for the purpose of identification of lubricants and suspected stains adhered to victims in traffic accidents. As the results, it was found that each lubricant showed a characteristic isotachophreogram even if they were manufactured by the same maker, and that the isotachopherogram of the lubricant changed in proportion to the running distance of an automobile. Each lubricant had its own changing rate. Moreover, A, B, C heavy oils, asphalt, soy sauce and sauce, which apparently resembled lubricants when they adhered to victims, were analysed with this method. They were found to be clearly different from lubricants in isotachopherogram and they could be discriminated from lubricants. Therefore, it was found that lubricants could be easily identified or discriminated from other lubricants such as engine oils, gear oils and other oils by comparing their isotachopherograms obtained with this method in a short time. It was, however, difficult to suggest the maker of a lubricant from isotachopherogram. We conclude from these observations that isotachophoresis method is useful for the analysis of lubricants in case of traffic accidents.

  14. Friction of self-lubricating surfaces by ion beam techniques. Final technical report

    SciTech Connect

    Bhattacharya, R.S.; Rai, A.K.

    1992-05-01

    UES, Inc. conducted a research and development program designed to establish conditions for ion implantation/mixing of suitable additives into the surfaces of bulk ceramics and metals for obtaining self-lubricating low friction and wear characteristics. The substrates considered were ZrO{sub 2}, Al{sub 2}O{sub 3}, Si{sub 3}N{sub 4}, steel and Ni-base superalloy. The lubricant additives chosen were BaF{sub 2}/CaF{sub 2}Ag, MoS{sub 2}, WS{sub 2}and B{sub 2}O{sub 3}. The initial tasks of the program were to synthesis these lubricant compounds by co-implantation of constituent elements if sufficient beams of desired elements were obtained. The final tasks were to investigate high energy (MeV) ion mixing of deposited coatings as well as to investigate ion beam assisted deposition using low energy ion beams. It was shown that MoS{sub 2} can be synthesized by co-implantation of Mo{sup +} and S{sup +} in ceramic materials with appropriate choice of energies to obtain nearly overlapping depth profiles. The sliding life of DC magnetron sputtered MoS{sub 2} films of thicknesses {approximately}7500{Angstrom} on ceramic materials such as sapphire, Si{sub 3}N{sub 4} and ZrO{sub 3} were improved by ten to thousand fold after 2 Mev Ag{sup +} ion mixing. Ion beam assisted deposition (IBAD) and ion beam mixing were utilized to fabricate self-lubricating coatings of CaF{sub 2}/Ag and BaF/CaF{sub 2}/Ag composites.

  15. Rotor self-lubricating axial stop

    NASA Technical Reports Server (NTRS)

    Blount, Dale H.

    1988-01-01

    A series of lubricating plugs is located in the stationary backup face adjacent to the axial stop face of a rotating impeller mounted in a turbopump for pumping liquid oxygen or liquid hydrogen. The stop face and the backup face are those surfaces which engage when the axial load on the impeller exceeds the load balancing capability. The plugs have a truncated conical configuration so as to be trapped in the backup face, and are placed at varying radii on the face to provide complete surface lubrication. The plugs may be formed from Teflon, Kel-F or bronze filled Teflon.

  16. Rotor self-lubricating axial stop

    NASA Technical Reports Server (NTRS)

    Blount, Dale H. (Inventor)

    1989-01-01

    A plurality of lubricating plugs are disposed in the stationary backup face adjacent to the axial stop face of a rotating impeller mounted in a turbopump for pumping liquid oxygen or liquid hydrogen. The stop face and the backup face are those surfaces which engage when the axial load on the impeller exceeds the load balancing capability. The plugs have a truncated conical configuration so as to be trapped in the backup face, and are disposed at varying radii on the face to provide complete surface lubrication. The plugs may be formed from Teflon, Kel-F or bronze filled Teflon.

  17. Ionic liquid lubrication at electrified interfaces

    NASA Astrophysics Data System (ADS)

    Kong, Lingling; Huang, Wei; Wang, Xiaolei

    2016-06-01

    The lubrication performances of ionic liquids at electrified interfaces have been investigated by using a reciprocating sliding tribometer. Experimental results indicated that the lubricity of the confined ionic liquids was markedly affected by the application of external electric field and strong interface electric field strength could result in high friction. The influence was more pronounced for the ionic liquid with a shorter alkyl side chain in particular. The main reason of the friction increment might be ascribed to the electrically influenced surface adsorption where the charged ions were structured to form robust and ordered layers.

  18. Method for reclaiming waste lubricating oils

    DOEpatents

    Whisman, Marvin L.; Goetzinger, John W.; Cotton, Faye O.

    1978-01-01

    A method for purifying and reclaiming used lubricating oils containing additives such as detergents, antioxidants, corrosion inhibitors, extreme pressure agents and the like and other solid and liquid contaminants by preferably first vacuum distilling the used oil to remove water and low-boiling contaminants, and treating the dried oil with a solvent mixture of butanol, isopropanol and methylethyl ketone which causes the separation of a layer of sludge containing contaminants, unspent additives and oxidation products. After solvent recovery, the desludged oil is then subjected to conventional lubricating oil refining steps such as distillation followed by decolorization and deodorization.

  19. Sputtering technology in solid film lubrication

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1978-01-01

    Current and potential sputtering technology is reviewed as it applies primarily to the deposition of MoS2, though such lubricants as WS2 and PTFE are also considered. It is shown by electron microscopy and surface sensitive analytical techniques that the lubricating properties of sputtered MoS2 films are directly influenced by the sputtering parameters selected (i.e., power density, pressure, sputter etching, dc-biasing, etc.), substrate temperature, chemistry, topography, and environmental conditions during the friction test. Electron micrographs and diffractograms of sputtered MoS2 films clearly show the resultant changes in film morphology which affect film adherence and frictional properties.

  20. Comparison of friction and lubrication of different hip prostheses.

    PubMed

    Scholes, S C; Unsworth, A

    2000-01-01

    It is well documented that an important cause of osteolysis and subsequent loosening of replacement hip joints is polyethylene wear debris. To avoid this, interest has been renewed in metal-on-metal and ceramic-on-ceramic prostheses. Various workers have assessed the lubrication modes of different joints by measuring the friction at the bearing surfaces, using different lubricants. Measurements of friction factors of a series of hip prostheses were undertaken using carboxymethyl cellulose (CMC) fluids, silicone fluids, synovial fluid and different concentrations of bovine serum as the lubricant. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing CMC fluids or silicone fluids as the lubricant. Mixed lubrication was found to occur in the metal-on-metal (CoCrMo/CoCrMo) joints with all lubricants at a viscosity within the physiological range. This was also the case for the metal-on-plastic (CoCrMo/ultra-high molecular weight polyethylene) joints. The ceramic-on-ceramic (Al2O3/Al2O3) joints, however, exhibited full fluid film lubrication with the synthetic lubricants but mixed lubrication with the biological lubricants. Employing a biological fluid as the lubricant affected the friction to varying degrees when compared with the synthetic lubricants. In the case of the ceramic-on-ceramic joints it acted to increase the friction factor tenfold; however, for the metal-on-metal joints, biological fluids gave slightly lower friction than the synthetic lubricants did. This suggests that, when measuring friction and wear of artificial joints, a standard lubricant should be used.

  1. Lubricants or lubricant additives composed of ionic liquids containing ammonium cations

    DOEpatents

    Qu, Jun [Knoxville, TN; Truhan, Jr; John, J [Cookeville, TN; Dai, Sheng [Knoxville, TN; Luo, Huimin [Knoxville, TN; Blau, Peter J [Knoxville, TN

    2010-07-13

    A lubricant or lubricant additive is an ionic liquid alkylammonium salt. The alkylammonium salt has the structure R.sub.xNH.sub.(4-x).sup.+,[F.sub.3C(CF.sub.2).sub.yS(O).sub.2].sub.2N.sup- .- where x is 1 to 3, R is independently C.sub.1 to C.sub.12 straight chain alkyl, branched chain alkyl, cycloalkyl, alkyl substituted cycloalkyl, cycloalkyl substituted alkyl, or, optionally, when x is greater than 1, two R groups comprise a cyclic structure including the nitrogen atom and 4 to 12 carbon atoms, and y is independently 0 to 11. The lubricant is effective for the lubrication of many surfaces including aluminum and ceramics surfaces.

  2. Investigation of metallurgical coatings for automotive applications

    NASA Astrophysics Data System (ADS)

    Su, Jun Feng

    Metallurgical coatings have been widely used in the automotive industry from component machining, engine daily running to body decoration due to their high hardness, wear resistance, corrosion resistance and low friction coefficient. With high demands in energy saving, weight reduction and limiting environmental impact, the use of new materials such as light Aluminum/magnesium alloys with high strength-weight ratio for engine block and advanced high-strength steel (AHSS) with better performance in crash energy management for die stamping, are increasing. However, challenges are emerging when these new materials are applied such as the wear of the relative soft light alloys and machining tools for hard AHSS. The protective metallurgical coatings are the best option to profit from these new materials' advantages without altering largely in mass production equipments, machinery, tools and human labor. In this dissertation, a plasma electrolytic oxidation (PEO) coating processing on aluminum alloys was introduced in engine cylinder bores to resist wear and corrosion. The tribological behavior of the PEO coatings under boundary and starve lubrication conditions was studied experimentally and numerically for the first time. Experimental results of the PEO coating demonstrated prominent wear resistance and low friction, taking into account the extreme working conditions. The numerical elastohydrodynamic lubrication (EHL) and asperity contact based tribological study also showed a promising approach on designing low friction and high wear resistant PEO coatings. Other than the fabrication of the new coatings, a novel coating evaluation methodology, namely, inclined impact sliding tester was presented in the second part of this dissertation. This methodology has been developed and applied in testing and analyzing physical vapor deposition (PVD)/ chemical vapor deposition (CVD)/PEO coatings. Failure mechanisms of these common metallurgical hard coatings were systematically

  3. Vapor/Mist Used to Lubricate Gears After Loss of Primary Lubrication System

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Morales, Wilfredo

    2001-01-01

    Loss of lubrication in rotorcraft drive systems is a demanding requirement placed on drive system manufacturers. The drive system must operate for at least 30 minutes once the primary lubrication system has failed. This test is a military requirement that must be passed prior to certification of the aircraft. As new aircraft engines, operating at higher speeds, are fielded, the requirements for the drive system become increasingly more difficult. Also, the drive system must be lightweight, which minimizes the opportunity to use the gear bodies to absorb the tremendous amount of heating that takes place. In many cases, the amount of heat generated because of the high speed and load requires an emergency lubrication system that negatively impacts the aircraft's weight, complexity, and cost. A single mesh spur gear test rig is being used at the NASA Glenn Research Center to investigate possible emergency lubrication system improvements that will minimize the impact of having these systems onboard rotorcraft. A technique currently being investigated uses a vapor/mist system to lubricate the contacting surfaces after the primary lubrication system has been shut down. A number of tests were conducted in which the vapor/mist used the same lubricant as the primary system, but at a greatly reduced flow rate. Each test was initiated with the primary lubrication system operational and at steady-state conditions for a given speed and load. Then the primary lubrication system was shut down, and the vapor/mist lubrication system was initiated. An example of the tests conducted is shown in the figures. These preliminary tests have uncovered a mechanism that provides a lubricious, carbonaceous solid on the surface that actually reduces the surface temperature of the meshing gear teeth during operation. Surface analysis of the carbonaceous solid revealed it was graphitic. This mechanism is the synthetic lubricant "coking" on the active profile of the gears, which reduces the

  4. The use of screening tests in spacecraft lubricant evaluation

    NASA Technical Reports Server (NTRS)

    Kalogeras, Chris; Hilton, Mike; Carre, David; Didziulis, Stephen; Fleischauer, Paul

    1993-01-01

    A lubricant screening test fixture has been devised in order to satisfy the need to obtain lubricant performance data in a timely manner. This fixture has been used to perform short-term tests on potential lubricants for several spacecraft applications. The results of these tests have saved time by producing qualitative performance rankings of lubricant selections prior to life testing. To date, this test fixture has been used to test lubricants for 3 particular applications. The qualitative results from these tests have been verified by life test results and have provided insight into the function of various anti-wear additives.

  5. Elastohydrodynamic Lubrication with Polyolester Lubricants and HFC Refrigerants, Final Report, Volume 1

    SciTech Connect

    Gunsel, Selda; Pozebanchuk, Michael

    1999-04-01

    The objective of this study was to investigate the film formation properties of refrigeration lubricants using the ultrathin film elastohydrodynamic (EHD) interferometry technique and to study the effects of refrigerants on film formation. Film thickness measurements were conducted as a function of lubricant viscosity, speed, temperature, and refrigerant concentration. Based on the EHD film thickness data, effective pressure-viscosity coefficients were calculated for the test fluids at different temperatures and the effects of refrigerants on pressure-viscosity properties were investigated.

  6. 7 CFR 3201.14 - Penetrating lubricants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the product as a percent of the weight (mass) of the total organic carbon in the finished product. (c... re-refined lubricating oil products. Under the Resource Conservation and Recovery Act of 1976.... The designation can be found in the Comprehensive Procurement Guideline, 40 CFR 247.11....

  7. 7 CFR 3201.14 - Penetrating lubricants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the product as a percent of the weight (mass) of the total organic carbon in the finished product. (c... re-refined lubricating oil products. Under the Resource Conservation and Recovery Act of 1976.... The designation can be found in the Comprehensive Procurement Guideline, 40 CFR 247.11....

  8. 7 CFR 3201.14 - Penetrating lubricants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the product as a percent of the weight (mass) of the total organic carbon in the finished product. (c... re-refined lubricating oil products. Under the Resource Conservation and Recovery Act of 1976.... The designation can be found in the Comprehensive Procurement Guideline, 40 CFR 247.11....

  9. Piezoviscous effects in nonconformal contacts lubricated hydrodynamically

    NASA Technical Reports Server (NTRS)

    Jeng, Y. R.; Hamrock, B. J.; Brewe, D. E.

    1985-01-01

    The analysis is concerned with the piezoviscous-rigid regime of lubrication for the general case of elliptical contacts. In this regime several formulas of the lubricant film thickness have been proposed by Hamrock and Dowson, by Dowson et al., and more recently by Houpert. However, either they do not include the load parameter W, which has a strong effect on film thickness, or they overestimate the film thickness by using the Barus formula for pressure-viscosity characteristics. The Roelands formula was used for the pressure-viscosity relationship. The effects of the dimensionless load, speed, and materials parameters, the radius ratio, and the lubricant entrainment direction were investigated. The dimensionless load parameter was varied over a range of one order of magnitude. The dimensionless speed parameter was varied by 5.6 times the lowest value. Conditions corresponding to the use of solid materials of steel, bronze, and silicon nitride and lubricants of paraffinic and naphthenic mineral oil were considered in obtaining the exponent in the dimensionless materials parameter. The radius ratio was varied from 0.2 to 64 (a configuration approaching a line contact). Forty-one cases were used in obtaining a minimum film thickness formula. Contour plots indicate in detail the pressure developed between the contacting solids.

  10. Fully flooded elastohydrodynamic lubricated elliptical contacts

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1980-01-01

    Emphasis is on fully flooded, elastohydrodynamic lubricated, elliptical contacts. A fully flooded conjunction is one in which the film thickness is not significantly changed when the amount of lubricant is increased. A brief description of the relevant equations used in the elastohydrodynamic lubrication of elliptical contacts is given. The most important practical aspect of the elastohydrodynamic theory is the determination of the minimum film thickness within the contact. The maintenance of a fluid film of adequate magnitude is an essential feature of the correct operation of lubricated machine elements. The results presented show the influence of contact geometry on minimum film thickness as expressed by the ellipticity parameter and the dimensionless speed, load, and materials parameters. Film thickness equations are developed for materials of high elastic modulus, such as metal, and for materials of low elastic modulus, such as rubber. In addition to the film thickness equations that are developed, plots of pressure and film thickness are presented. These theoretical solutions for film thickness have all the essential features of previously reported experimental observations based on optical interferometry. Correlation between theory and experiments is also presented.

  11. Aqueous rust-inhibiting and lubricating compositions

    SciTech Connect

    Brandolese, E.

    1983-06-14

    Rust-inhibiting compounds, especially for aqueous systems such as tool-lubricating emulsions for machine tools and which consist of amine salts of a number of monoaminoalkylene dicarboxylic acids are disclosed. These rust-inhibitors are used in combination with water and an alkanolamine. Examples and test results are given.

  12. Improvement of lubricant materials using ruthenium isomerization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production of an effective industrial lubricant additive from vegetable oils is a high profile and difficult undertaking. One candidate is alkyl 9(10)-dibutylphosphonostearate, which has been made through a radical transformation of alkyl 9-cis-octadecanoate. It is effective, but still suffers from ...

  13. Parched elastohydrodynamic lubrication: Instrumentation and procedure

    NASA Technical Reports Server (NTRS)

    Schritz, Bryan; Jones, William R., Jr.; Prahl, Joseph; Jansen, Ralph

    1991-01-01

    A counter rotating bearing rig was designed and constructed to study transient elastohydrodynamic lubrication phenomena. New instrumentation is described and test procedures are documented. Ball and race speed measurement systems and the capacitance (film thickness) measurement system were upgraded. Methods for measuring bearing torque and race temperatures were implemented.

  14. Tribology: Friction, lubrication, and wear technology

    NASA Technical Reports Server (NTRS)

    Blau, Peter J.

    1993-01-01

    The topics are presented in viewgraph form and include the following: introduction and definitions of terms; friction concepts; lubrication technology concepts; wear technology concepts; and tribological transitions. This document is designed for educators who seek to teach these concepts to their students.

  15. Considerations on the lubrication of spacecraft mechanisms

    NASA Technical Reports Server (NTRS)

    Briscoe, M.; Todd, M. J.

    1983-01-01

    Space tribology and a number of precepts to guide designers in its application are discussed. Of the many techniques available all, without exception, have limitations in performance. Two processes are discussed in more detail and their limitations identified. Some performance results on a liquid space lubricant are given.

  16. Protein-mediated boundary lubrication in arthroplasty.

    PubMed

    Heuberger, M P; Widmer, M R; Zobeley, E; Glockshuber, R; Spencer, N D

    2005-04-01

    Wear of articulated surfaces can be a major lifetime-limiting factor in arthroplasty. In the natural joint, lubrication is effected by the body's natural synovial fluid. Following arthroplasty, and the subsequent reformation of the synovial membrane, a fluid of similar composition surrounds the artificial joint. Synovial fluid contains, among many other constituents, a substantial concentration of the readily adsorbing protein albumin. The ability of human serum albumin to act as a boundary lubricant in joint prostheses has been investigated using a pin-on-disc tribometer. Circular dichroism spectroscopy was employed to follow the temperature- and time-dependent conformational changes of human serum albumin in the model lubricant solution. Effects of protein conformation and polymer surface hydrophilicity on protein adsorption and the resulting friction in the boundary lubrication regime have been investigated. Unfolded proteins preferentially adsorb onto hydrophobic polymer surfaces, where they form a compact, passivating layer and increase sliding friction-an effect that can be largely suppressed by rendering the substrate more hydrophilic. A molecular model for protein-mediated boundary friction is proposed to consolidate the observations. The relevance of the results for in vivo performance and ex vivo hip-joint testing are discussed.

  17. Mechanism of lubrication by tricresylphosphate (TCP)

    NASA Technical Reports Server (NTRS)

    Faut, O. D.; Buckley, D. H.

    1984-01-01

    The coefficient of friction was measured as a function of temperature on a pin-on-disk tribometer. Pins and disks of 440C and 52100 steels were lubricated with tricresylphosphate (TCP), 3.45 percent TCP in squalene, and pure squalene. The M-50 pins and disks were lubricated with 3.45 percent TCP in squalene and pure squalene. Experiments were conducted under limited lubrication conditions in dry ( 100 ppm H2O) air and dry ( pp H2O) nitrogen at 50 rpm (equivalent to a sliding velocity of 13 cm sec) and a constant load of 9.8 N (1 kg). Characteristic temperatures T sub r were identified for TCP on 52100 steel and for squalene on M-50 and 52100 steels, where the friction decreased because of a chemical reaction between the lubricant and the metal surface. The behavior of squalene obscured the influence of 3.45 percent TCP solute on the friction of the system. Wear volume measurements demonstrated that wear was lowest at temperatures just above T sub r. Comparing the behavior of TCP on M-50, 440C, and 52100 steels revealed that the TCP either reacted to give T sub r behavior or produced initial failure in the temperature range 223 + or - 5 C.

  18. Freon 21 bearing lubrication and coolant system

    NASA Technical Reports Server (NTRS)

    Bodensieck, E. J.; Gustafson, M. J.

    1972-01-01

    Lubrication and cooling of turbopump rotor bearings by liquid Freon 21 is reported. Freon expands in rotor bearing and acts as heat sink by removing heat during warming and evaporation. Gaseous Freon is removed by vacuum pump controlling rotor chamber operation.

  19. Exploring Low Emission Lubricants for Diesel Engines

    SciTech Connect

    Perez, J. M.

    2000-07-06

    A workshop to explore the technological issues involved with the removal of sulfur from lubricants and the development of low emission diesel engine oils was held in Scottsdale, Arizona, January 30 through February 1, 2000. It presented an overview of the current technology by means of panel discussions and technical presentations from industry, government, and academia.

  20. Lubricant effect of rate-of-loading

    SciTech Connect

    Gleeson, J.B.

    1995-11-01

    A series of tests were conducted to establish the performance of a motor operated valve (MOV) stem lubricant. Battelle has assembled a MOV test stand to provide a means to test valve actuators and stems with representative valve load profiles and to accurately measure the actuator performance. The facility duplicates an actual MOV except that the stem thrust loads are generated hydraulically and seating loads are generated by mechanical stops. These tests were conducted at a high torque switch setting on a Limitorque SMB-0. Stem-stemnut pairs with known rate-of-loading (ROL) effects ranging from approximately zero to 30% were tested. The stems were lubricated with Mobil 28; a nuclear-grade synthetic grease. A test with a slow, linearly increasing load profile with torque switch trip occurring prior to seating (ramp test), was used to establish the magnitude of the ROL effect for a particular stem-stemnut. Data from these experiments were compared with results of similar EPRI tests which used different stem lubricants. Results with Mobil 28 yielded unexpected, consistent reduced ROL effects. In addition, the thread pressure threshold for limiting ROL effects was significantly reduced. A model of the squeeze film phenomena was developed to explain the experimental results. The model shows that the basic rheological properties of the lubricant, the thread composite surface roughness, and the thread type all have a significant influence on the magnitude of ROL effects.

  1. Friction, wear, and lubrication in vacuum

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1971-01-01

    A review of studies and observations on the friction, wear, and lubrication behavior of materials in a vacuum environment is presented. The factors that determine and influence friction and wear are discussed. They include topographical, physical, mechanical, and the chemical nature of the surface. The effects of bulk properties such as deformation characteristics, fracture behavior, and structure are included.

  2. Fuels and Lubricants. Selecting and Storing.

    ERIC Educational Resources Information Center

    Parady, W. Harold; Colvin, Thomas S.

    The manual presents basic information for the person who plans to operate or service tractors, trucks, industrial engines, and automobiles. It tells how to select the proper fuels and lubricants and how to store them properly. Although there are no prerequisites to the study of the text, a general knowledge of engines and mobile-type vehicles is…

  3. Self-lubricating fluorine shaft seal material

    NASA Technical Reports Server (NTRS)

    Munk, W. R.

    1970-01-01

    Lubricating film is produced by a reaction of fluorine with a composite of aluminum oxide and nickel powder. The rate of nickel fluoride generation is proportional to the rate at which the fluoride is rubbed off the surface, allowing the seal to operate with the lowest possible heating.

  4. Synergistic effects of silver films and synthetic lubricants on boundary-lubrication behavior of ceramics

    SciTech Connect

    Erdemir, A.; Ajayi, O.O.; Erck, R.A.; Fenske, G.R.; Nichols, F.A. . Materials and Components Technology Div.); Ockers, J.M. ); Kar, K.K.; Morgan, T.A. )

    1992-11-01

    In a study seeking to achieve low friction and low wear on ceramic materials, we investigated a new lubrication concept that explores the synergistic effect of a silver film and a recently developed synthetic oil on the boundary lubrication behavior of silicon nitride (Si[sub 3]N[sub 4]) ceramics. Friction and wear tests were performed on a wear test machine at temperatures up to 380[degree]C. Under the test conditions explored, we found that the friction coefficients of Si[sub 3]N[sub 4]/Si[sub 3]N[sub 4] test pairs during oil-lubricated sliding tests ranged from 0.1 to 0.35, and the average wear rates of ceramic pins were between 3 [times] 10[sup [minus]7] and 10[sup [minus]6] mm[sup 3] N[sup [minus]1] m[sup [minus]1], depending on test temperature. Concurrent use of lubricant oil with a silver film had a synergistic effect on both friction and wear. When silver films are used at oil-lubricated sliding interfaces, wear rates of both pins and flats were reduced to unmeasurable levels and the friction coefficients were reduced by factors of two to ten below those of the test pairs without silver films. Beneficial synergistic effects of silver films and synthetic oil on the boundary-lubrication behavior of ceramics were more pronounced at elevated test temperatures than at room temperature.

  5. Synergistic effects of silver films and synthetic lubricants on boundary-lubrication behavior of ceramics

    SciTech Connect

    Erdemir, A.; Ajayi, O.O.; Erck, R.A.; Fenske, G.R.; Nichols, F.A.; Ockers, J.M.; Kar, K.K.; Morgan, T.A.

    1992-11-01

    In a study seeking to achieve low friction and low wear on ceramic materials, we investigated a new lubrication concept that explores the synergistic effect of a silver film and a recently developed synthetic oil on the boundary lubrication behavior of silicon nitride (Si{sub 3}N{sub 4}) ceramics. Friction and wear tests were performed on a wear test machine at temperatures up to 380{degree}C. Under the test conditions explored, we found that the friction coefficients of Si{sub 3}N{sub 4}/Si{sub 3}N{sub 4} test pairs during oil-lubricated sliding tests ranged from 0.1 to 0.35, and the average wear rates of ceramic pins were between 3 {times} 10{sup {minus}7} and 10{sup {minus}6} mm{sup 3} N{sup {minus}1} m{sup {minus}1}, depending on test temperature. Concurrent use of lubricant oil with a silver film had a synergistic effect on both friction and wear. When silver films are used at oil-lubricated sliding interfaces, wear rates of both pins and flats were reduced to unmeasurable levels and the friction coefficients were reduced by factors of two to ten below those of the test pairs without silver films. Beneficial synergistic effects of silver films and synthetic oil on the boundary-lubrication behavior of ceramics were more pronounced at elevated test temperatures than at room temperature.

  6. Black Molecular Adsorber Coatings for Spaceflight Applications

    NASA Technical Reports Server (NTRS)

    Abraham, Nithin Susan; Hasegawa, Mark Makoto; Straka, Sharon A.

    2014-01-01

    The molecular adsorber coating is a new technology that was developed to mitigate the risk of on-orbit molecular contamination on spaceflight missions. The application of this coating would be ideal near highly sensitive, interior surfaces and instruments that are negatively impacted by outgassed molecules from materials, such as plastics, adhesives, lubricants, epoxies, and other similar compounds. This current, sprayable paint technology is comprised of inorganic white materials made from highly porous zeolite. In addition to good adhesion performance, thermal stability, and adsorptive capability, the molecular adsorber coating offers favorable thermal control characteristics. However, low reflectivity properties, which are typically offered by black thermal control coatings, are desired for some spaceflight applications. For example, black coatings are used on interior surfaces, in particular, on instrument baffles for optical stray light control. Similarly, they are also used within light paths between optical systems, such as telescopes, to absorb light. Recent efforts have been made to transform the white molecular adsorber coating into a black coating with similar adsorptive properties. This result is achieved by optimizing the current formulation with black pigments, while still maintaining its adsorption capability for outgassing control. Different binder to pigment ratios, coating thicknesses, and spray application techniques were explored to develop a black version of the molecular adsorber coating. During the development process, coating performance and adsorption characteristics were studied. The preliminary work performed on black molecular adsorber coatings thus far is very promising. Continued development and testing is necessary for its use on future contamination sensitive spaceflight missions.

  7. Black molecular adsorber coatings for spaceflight applications

    NASA Astrophysics Data System (ADS)

    Abraham, Nithin S.; Hasegawa, Mark M.; Straka, Sharon A.

    2014-09-01

    The molecular adsorber coating is a new technology that was developed to mitigate the risk of on-orbit molecular contamination on spaceflight missions. The application of this coating would be ideal near highly sensitive, interior surfaces and instruments that are negatively impacted by outgassed molecules from materials, such as plastics, adhesives, lubricants, epoxies, and other similar compounds. This current, sprayable paint technology is comprised of inorganic white materials made from highly porous zeolite. In addition to good adhesion performance, thermal stability, and adsorptive capability, the molecular adsorber coating offers favorable thermal control characteristics. However, low reflectivity properties, which are typically offered by black thermal control coatings, are desired for some spaceflight applications. For example, black coatings are used on interior surfaces, in particular, on instrument baffles for optical stray light control. Similarly, they are also used within light paths between optical systems, such as telescopes, to absorb light. Recent efforts have been made to transform the white molecular adsorber coating into a black coating with similar adsorptive properties. This result is achieved by optimizing the current formulation with black pigments, while still maintaining its adsorption capability for outgassing control. Different binder to pigment ratios, coating thicknesses, and spray application techniques were explored to develop a black version of the molecular adsorber coating. During the development process, coating performance and adsorption characteristics were studied. The preliminary work performed on black molecular adsorber coatings thus far is very promising. Continued development and testing is necessary for its use on future contamination sensitive spaceflight missions.

  8. Lubricant and additive effects on spur gear fatigue life

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Zaretsky, E. V.; Scibbe, H. W.

    1985-01-01

    Spur gear endurance tests were conducted with six lubricants using a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The sixth lubricant was divided into four batches each of which had a different additive content. Lubricants tested with a phosphorus-type load carrying additive showed a statistically significant improvement in life over lubricants without this type of additive. The presence of sulfur type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears. No statistical difference in life was produced with those lubricants of different base stocks but with similar viscosity, pressure-viscosity coefficients and antiwear additives. Gears tested with a 0.1 wt % sulfur and 0.1 wt % phosphorus EP additives in the lubricant had reactive films that were 200 to 400 (0.8 to 1.6 microns) thick.

  9. Lubricant and additive effects on spur gear fatigue life

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Zaretsky, E. V.; Scibbe, H. W.

    1986-01-01

    Spur gear endurance tests were conducted with six lubricants using a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The sixth lubricants was divided into four batches each of which had a different additive content. Lubricant tested with a phosphorus-type load carrying additive showed a statistically significant improvement in life over lubricants without this type of additive. The presence of sulfur type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears. No statistical difference in life was produced with those lubricants of different base stocks but with similar viscosity, pressure-viscosity coefficients and antiwar additives. Gears tested with a 0.1 wt pct sulfur and 0.1 wt pct phosphorus EP additives in the lubricant had reactive films that were 200 to 400 (0.8 to 1.6 microns) thick.

  10. Intermediate coating layer for high temperature rubbing seals for rotary regenerators

    DOEpatents

    Schienle, James L.; Strangman, Thomas E.

    1995-01-01

    A metallic regenerator seal is provided having multi-layer coating comprising a NiCrAlY bond layer, a yttria stabilized zirconia (YSZ) intermediate layer, and a ceramic high temperature solid lubricant surface layer comprising zinc oxide, calcium fluoride, and tin oxide. Because of the YSZ intermediate layer, the coating is thermodynamically stable and resists swelling at high temperatures.

  11. Microfog lubricant application system for advanced turbine engine components, phase 3. [wetting characteristics and deposit forming tendencies of lubricants

    NASA Technical Reports Server (NTRS)

    Petrucco, R. J.; Leonardi, S. J.

    1973-01-01

    The wetting characteristics and deposit forming tendencies of a series of lubricants were evaluated using a microfog jet delivery system to wet a flat heated rotating disc. The performances of the nine lubricants are discussed in terms of the various testing parameters which include temperature, disc speed and lubricant gas flow rates. Also discussed are the heat transfer characteristics of two of the lubricants on that same plane disc specimen. The wetting characteristics and heat transfer characteristics of one of the lubricants on a complex disc simulating bearing geometry are also discussed.

  12. Superhard self-lubricating AlMgB14 films for microelectromechanical devices

    NASA Astrophysics Data System (ADS)

    Tian, Y.; Bastawros, A. F.; Lo, C. C. H.; Constant, A. P.; Russell, A. M.; Cook, B. A.

    2003-10-01

    Performance and reliability of microelectromechanical system (MEMS) components can be enhanced dramatically through the incorporation of protective thin-film coatings. Current-generation MEMS devices prepared by the lithographie-galvanoformung-abformung (LIGA) technique employ transition metals such as Ni, Cu, Fe, or alloys thereof, and hence lack stability in oxidizing, corrosive, and/or high-temperature environments. Fabrication of a superhard self-lubricating coating based on a ternary boride compound AlMgB14 described in this letter has great potential in protective coating technology for LIGA microdevices. Nanoindentation tests show that the hardness of AlMgB14 films prepared by pulsed laser deposition ranges from 45 GPa to 51 GPa, when deposited at room temperature and 573 K, respectively. Extremely low friction coefficients of 0.04-0.05, which are thought to result from a self-lubricating effect, have also been confirmed by nanoscratch tests on the AlMgB14 films. Transmission electron microscopy studies show that the as-deposited films are amorphous, regardless of substrate temperature; however, analysis of Fourier transform infrared spectra suggests that the higher substrate temperature facilitates the formation of the B12 icosahedral framework, therefore leading to the higher hardness.

  13. A dynamic rheological model for thin-film lubrication

    NASA Astrophysics Data System (ADS)

    Zhang, Xiang-Jun; Huang, Ying; Guo, Yan-Bao; Tian, Yu; Meng, Yong-Gang

    2013-01-01

    In this study, the effects of the non-Newtonian rheological properties of the lubricant in a thin-film lubrication regime between smooth surfaces were investigated. The thin-film lubrication regime typically appears in Stribeck curves with a clearly observable minimum coefficient of friction (COF) and a low-COF region, which is desired for its lower energy dissipation. A dynamic rheology of the lubricant from the hydrodynamic lubrication regime to the thin-film lubrication regime was proposed based on the convected Maxwell constitutive equation. This rheology model includes the increased relaxation time and the yield stress of the confined lubricant thin film, as well as their dependences on the lubricant film thickness. The Deborah number (De number) was adopted to describe the liquid-solid transition of the confined lubricant thin film under shearing. Then a series of Stribeck curves were calculated based on Tichy's extended lubrication equations with a perturbation of the De number. The results show that the minimum COF points in the Stribeck curve correspond to a critical De number of 1.0, indicating a liquid-to-solid transition of the confined lubricant film. Furthermore, the two proposed parameters in the dynamic rheological model, namely negative slipping length b (indicating the lubricant interfacial effect) and the characteristic relaxation time λ0, were found to determine the minimum COF and the width of the low-COF region, both of which were required to optimize the shape of the Stribeck curve. The developed dynamic rheological model interprets the correlation between the rheological and interfacial properties of lubricant and its lubrication behavior in the thin-film regime.

  14. Design and fundamental understanding of Minimum Quantity Lubrication (MQL) assisted grinding using advanced nanolubricants

    NASA Astrophysics Data System (ADS)

    Kalita, Parash

    of ductile iron and alloy steel. An extensive investigation on MQL-assisted grinding using vitrified aluminum oxide wheel under varied infeed and lubrication condition was carried out with the scope of documenting the process efficiency and lubrication mechanisms of the nanolubricants. Experimental results showed that MQL grinding with nanolubricants minimized the non-productive outputs of the grinding process by reducing frictional losses at the abrasive grain-workpiece interfaces, energy consumption, wheel wear, grinding zone temperatures, and friction-induced heat generation. Use of nanolubricants in MQL yielded superior productivity by producing surface roughness as low as 0.35 μm and grinding efficiencies that were four times higher as compared to those obtained from flood grinding. Repeatable formation of tribochemical films of antifriction, antiwear, and extreme pressure chemical species in between the contact asperities of abrasive crystals and work material was identified with nanolubricants. The tribological behavior was characterized by this synergistic effect of the antiwear, antifriction, and load carrying chemical species that endured grain-workpiece seizures and reduced adhesion friction between the contact surfaces. Delivery of organic coated Molybdenum Disulphide nanoparticles by anchoring on the natural porosity of the abrasive wheel and eventually, sliding-induced interfacial deformation into tribolayers and alignment at the grinding zone were established as the lubrication mechanisms of the nanolubricants. These mechanisms were further validated from tribological evaluations of lubricated cubic boron nitride (cBN) superabrasives-1045 steel sliding pairs on a reciprocating tribotest rig resembling the tool-lubricant-workpiece interactions of MQL-assisted grinding.

  15. Design of nanocomposite polymer coatings for MEMS applications

    NASA Astrophysics Data System (ADS)

    Julthongpiput, Duangrut

    The recent evolution in microelectronics of combining electrical and mechanical functions has brought about the exciting field of microelectromechanical system (MEMS). As the dimensions of the components shrink, adhesion, stiction, friction, and wear become a significant technological barrier for the successful development of durable microdevices. In this thesis, we investigate wear-resistant, nanocomposite, molecular coatings from advanced polymers with controlled nanomechanical and nanotribological properties from the prospective of long-term applications for MEMS. We discuss fundamentals governing the mechanical and tribological properties on a micro scale associated with the morphology and microstructure of these molecular coatings. In order to fabricate wear-resistant and superelastic molecular coatings, several types of the molecular designs are proposed and tested in this work. All designs are based on chemical attachment of the polymer layers onto a functionalized silicon surface. We focus on developing two different kinds of molecular coatings: reinforced elastomeric layers from grafted block-copolymers and polymer brush layers grown by the "grafted to" technique. A more complicated design included bilayered nanocomposite coatings consisting of a hard polymer layer placed on the top of an elastomeric layer to regulate surface adhesion and to increase surface stiffness of nanocomposite bilayers. Another design incorporates a paraffinic oil component to assure the presence of highly mobile molecules inside of the elastomeric phase. This oily fraction can be a source of an instant supply of mobile lubricant to a deformed contact area, thus providing potential self-lubrication and self-healing mechanisms for surface areas affected by excessive deformation. We observed that the interfacial assemblies, as presented in this paper, exhibited very low friction coefficient, low stiction, and better wear stability as compared to other, non-structured, non

  16. Urinary catheter with polyurethane coating modified by ion implantation

    NASA Astrophysics Data System (ADS)

    Kondyurina, I.; Nechitailo, G. S.; Svistkov, A. L.; Kondyurin, A.; Bilek, M.

    2015-01-01

    A low friction urinary catheter that could be used without a lubricant is proposed in this work. A polyurethane coating was synthesised on the surface of a metal guide wire catheter. Ion implantation was applied to surface modify the polyurethane coating. FTIR ATR, wetting angle, AFM and friction tests were used for analysis. Low friction was found to be provided by the formation of a hard carbonised layer on the polyurethane surface.

  17. Tribological evaluation of piston skirt/cylinder liner contact interfaces under boundary lubrication conditions.

    SciTech Connect

    Demas, N. G.; Erck, R. A.; Fenske, G. R.; Energy Systems

    2010-03-01

    The friction and wear between the piston and cylinder liner significantly affects the performance of internal combustion engines. In this paper, segments from a commercial piston/cylinder system were tribologically tested using reciprocating motion. The tribological contact consisted of aluminium alloy piston segments, either uncoated, coated with a graphite/resin coating, or an amorphous hydrogenated carbon (a-C : H) coating, in contact with gray cast iron liner segments. Tests were conducted in commercial synthetic motor oils and base stocks at temperatures up to 120 C with a 2 cm stroke length at reciprocating speeds up to 0.15 m s{sup -1}. The friction dependence of these piston skirt and cylinder liner materials was studied as a function of load, sliding speed and temperature. Specifically, an increase in the sliding speed led to a decrease in the friction coefficient below approximately 70 C, while above this temperature, an increase in sliding speed led to an increase in the friction coefficient. The presence of a coating played an important role. It was found that the graphite/resin coating wore quickly, preventing the formation of a beneficial tribochemical film, while the a-C : H coating exhibited a low friction coefficient and provided significant improvement over the uncoated samples. The effect of additives in the oils was also studied. The tribological behaviour of the interface was explained based on viscosity effects and subsequent changes in the lubrication regime, formation of chemical and tribochemical films.

  18. The effect of lubricant constituents on lubrication mechanisms in hip joint replacements.

    PubMed

    Nečas, David; Vrbka, Martin; Urban, Filip; Křupka, Ivan; Hartl, Martin

    2015-03-01

    The aim of the present paper is to provide a novel experimental approach enabling to assess the thickness of lubricant film within hip prostheses in meaning of the contribution of particular proteins. Thin film colorimetric interferometry was combined with fluorescent microscopy finding that a combination of optical methods can help to better understand the interfacial lubrication processes in hip replacements. The contact of metal femoral head against a glass disc was investigated under various operating conditions. As a test lubricant, the saline solution containing the albumin and γ-globulin in a concentration 2:1 was employed. Two different mean speeds were applied, 5.7 and 22mm/s, respectively. The measurements were carried out under pure rolling, partial negative and partial positive sliding conditions showing that kinematic conditions substantially affects the formation of protein film. Under pure rolling conditions, an increasing tendency of lubricant film independently on rolling speed was detected, while the total thickness of lubricant film can be attributed mainly to albumin. When the ball was faster than the disc (negative sliding), a very thin lubricant film was observed for lower speed with no significant effect of particular proteins. The increase in sliding speed led to the increase of film thickness mainly caused due to the presence of γ-globulin. On the contrary, when the disc was faster than the ball (positive sliding), the film formation was very complex and time dependent while both of the studied proteins have shown any qualitative change during the test, however the effect of albumin seems to be much more important. Since a very good agreement of the results was obtained, it can be concluded that the approach consisting of two optical methods can provide the fundamental information about the lubricant film formation in meaning of particular proteins while the simultaneous presence of other constituents in model synovial fluid. PMID

  19. Compilation of diamond-like carbon properties for barriers and hard coatings

    SciTech Connect

    Outka, D.A.; Hsu, Wen L.; Phillips, K.; Boehme, D.R.; Yang, N.Y.C.; Ottesen, D.K.; Johnsen, H.A.; Clift, W.M.; Headley, T.J.

    1994-05-01

    Diamond-like carbon (DLC) is an amorphous form of carbon which resembles diamond in its hardness, lubricity, and resistance to chemical attack. Such properties make DLC of interest for use in barrier and hard coating technology. This report examines a variety of properties of DLC coatings. This includes examining substrates on which DLC coatings can be deposited; the resistance of DLC coatings to various chemical agents; adhension of DLC coatings; and characterization of DLC coatings by electron microscopy, FTIR, sputter depth profiling, stress measurements and nanoindentation.

  20. Effect of glucosamine sulfate on surface interactions and lubrication by hydrogenated soy phosphatidylcholine (HSPC) liposomes.

    PubMed

    Gaisinskaya-Kipnis, Anastasia; Jahn, Sabrina; Goldberg, Ronit; Klein, Jacob

    2014-11-10

    Glucosamine sulfate (GAS) is a charged monosaccharide molecule that is widely used as a treatment for osteoarthritis, a joint disease related to friction and lubrication of articular cartilage. Using a surface force balance, we examine the effect of GAS on normal and, particularly, on shear (frictional) interactions between surfaces in an aqueous environment coated with small unilamellar vesicles (SUVs), or liposomes, of hydrogenated soy phosphatidylcholine (HSPC). We examine the effect of GAS solution, pure water, and salt solution (0.15 M NaNO3) both inside and outside the vesicles. Cryoscanning electron microscopy shows a closely packed layer of liposomes whose morphology is affected only slightly by GAS. HSPC-SUVs with encapsulated GAS are stable upon shear at high compressions (>100 atm) and provide very good lubrication when immersed both in pure water and physiological-level salt solutions (in the latter case, the liposomes are exceptionally stable and lubricious up to >400 atm). The low friction is attributed to several parameters based on the hydration lubrication mechanism.

  1. Boundary mode lubrication of articular cartilage by recombinant human lubricin.

    PubMed

    Gleghorn, Jason P; Jones, Aled R C; Flannery, Carl R; Bonassar, Lawrence J

    2009-06-01

    Lubrication of cartilage involves a variety of physical and chemical factors, including lubricin, a synovial glycoprotein that has been shown to be a boundary lubricant. It is unclear how lubricin boundary lubricates a wide range of bearings from tissue to artificial surfaces, and if the mechanism is the same for both soluble and bound lubricin. In the current study, experiments were conducted to investigate the hypothesis that recombinant human lubricin (rh-lubricin) lubricates cartilage in a dose-dependent manner and that soluble and bound fractions of rh-lubricin both contribute to the lubrication process. An rh-lubricin dose response was observed with maximal lubrication achieved at concentrations of rh-lubricin greater than 50 microg/mL. A concentration-response variable-slope model was fit to the data, and indicated that rh-lubricin binding to cartilage was not first order. The pattern of decrease in equilibrium friction coefficient indicated that aggregation of rh-lubricin or steric arrangement may regulate boundary lubrication. rh-lubricin localized at the cartilage surface was found to lubricate a cartilage-glass interface in boundary mode, as did soluble rh-lubricin at high concentrations (150 microg/mL); however, the most effective lubrication occurred when both soluble and bound rh-lubricin were present at the interface. These findings point to two distinct mechanisms by which rh-lubricin lubricates, one mechanism involving lubricin bound to the tissue surface and the other involving lubricin in solution.

  2. Effects of silver and group 2 fluorides addition to plasma sprayed chromium carbide high temperature solid lubricant for foil gas bearing to 650 deg C

    NASA Technical Reports Server (NTRS)

    Wagner, R. C.; Sliney, H. E.

    1984-01-01

    A new self-lubricating coating composition of nickel aluminide-bonded chromium carbide formulated with silver and Group II fluorides was developed in a research program on high temperature solid lubricants. One of the proposed applications for this new coating composition is as a wide temperature spectrum solid lubricant for complaint foil gas bearings. Friction and wear properties were obtained using a foil gas bearing start/stop apparatus at temperatures from 25 to 650 C. The journals were Inconel 718. Some were coated with the plasma sprayed experimental coating, others with unmodified nickel aluminide/chromium carbide as a baseline for comparison. The addtitional components were provided to assist in achieving low friction over the temperature range of interest. Uncoated, preoxidized Inconel X-750 foil bearings were operated against these surfaces. The foils were subjected to repeated start/stop cycles under a 14-kPa (2-psi) bearing unit loading. Sliding contact occurred during lift-off and coastdown at surface velocities less than 6 m/s (3000 rpm). Testing continued until 9000 start/stop cycles were accumulated or until a rise in starting torque indicated the journal/bearing had failed. Comparison in coating performance as well as discussions of their properties and methods of application are given.

  3. Oxidation Effects on the Friction of Lubricants and Self-Lubricating Materials in the Enduring Stockpile

    SciTech Connect

    Dugger, M.T.; Peebles, D.E.; Ohlhausen, J.A.; Robinson, J.A.; Sorroche, E.H.; Fanska, J.

    1999-03-18

    Predictive models of solid lubricant performance are needed to determine the dynamic behavior of electromechanical devices after long periods of storage. X-ray photoelectron spectroscopy has been used to determine the kinetics of oxidation and sulfate formation for solid lubricants and self-lubricating materials containing MoS{sub 2}, exposed to a variety of oxidation conditions. The frictional performance of the lubricant has then been determined as a fi.mction of its surface chemistry and the ambient environment in which sliding takes place. Results indicate that surface sulfate formation governs the initial or start-up friction coefficient of MoS{sub 2}-containing films, while the composition of the ambient gas determines the steady-state friction coefficient. The dependence of the steady-state friction coefficient on the environment in which sliding takes place has been examined, and the results show that dynamic oxidation of surfaces having exposed metal has a major impact on friction. Surface oxidation is also shown to influence the frictional behavior of a self-lubricating composite material containing MoS{sub 2}.

  4. Lubrication at physiological pressures by polyzwitterionic brushes.

    PubMed

    Chen, Meng; Briscoe, Wuge H; Armes, Steven P; Klein, Jacob

    2009-03-27

    The very low sliding friction at natural synovial joints, which have friction coefficients of mu < 0.002 at pressures up to 5 megapascals or more, has to date not been attained in any human-made joints or between model surfaces in aqueous environments. We found that surfaces in water bearing polyzwitterionic brushes that were polymerized directly from the surface can have mu values as low as 0.0004 at pressures as high as 7.5 megapascals. This extreme lubrication is attributed primarily to the strong hydration of the phosphorylcholine-like monomers that make up the robustly attached brushes, and may have relevance to a wide range of human-made aqueous lubrication situations.

  5. Graphene oxide film as solid lubricant.

    PubMed

    Liang, Hongyu; Bu, Yongfeng; Zhang, Junyan; Cao, Zhongyue; Liang, Aimin

    2013-07-10

    As a layered material, graphene oxide (GO) film is a good candidate for improving friction and antiwear performance of silicon-based MEMS devices. Via a green electrophoretic deposition (EPD) approach, GO films with tunable thickness in nanoscale are fabricated onto silicon wafer in a water solution. The morphology, microstructure, and mechanical properties as well as the friction coefficient and wear resistance of the films were investigated. The results indicated that the friction coefficient of silicon wafer was reduced to 1/6 its value, and the wear volume was reduced to 1/24 when using GO film as solid lubricant. These distinguished tribology performances suggest that GO films are expected to be good solid lubricants for silicon-based MEMS/NEMS devices. PMID:23786494

  6. Thermal elastohydrodynamic lubrication of spur gears

    NASA Technical Reports Server (NTRS)

    Wang, K. L.; Cheng, H. S.

    1980-01-01

    An analysis and computer program called TELSGE were developed to predict the variations of dynamic load, surface temperature, and lubricant film thickness along the contacting path during the engagement of a pair of involute spur gears. The analysis of dynamic load includes the effect of gear inertia, the effect of load sharing of adjacent teeth, and the effect of variable tooth stiffness which are obtained by a finite-element method. Results obtained from TELSGE for the dynamic load distributions along the contacting path for various speeds of a pair of test gears show patterns similar to that observed experimentally. Effects of damping ratio, contact ratio, tip relief, and tooth error on the dynamic load were examined. In addition, two dimensionless charts are included for predicting the maximum equilibrium surface temperature, which can be used to estimate directly the lubricant film thickness based on well established EHD analysis.

  7. Self-Lubricating Composite Containing Chromium Oxide

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher (Inventor); Edmonds, Brian J. (Inventor)

    1999-01-01

    A self lubricating. friction and wear reducing composite material useful over a wide temperature range of from cryogenic temperature up to about 900 C. contains 60 80 wt. % of particulate Cr2O3, dispersed in a metal binder of a metal alloy containing Cr and at least 50 wt. % of Ni, Cr or a mature of Ni and Cr. It also contains 5-20 wt. % of a fluoride of at least one Group I, Group II or rare earth metal and. optionally, 5-20 wt. % of a low temperature lubricant metal, such as Ag. Au, Pt, Pd, Rh and Cu. This composite exhibits less oxidation instability and less abrasiveness than composites containing chromium carbide, is readily applied using plasma spray and can be ground and polished with a silicon carbide abrasive.

  8. Thermal elastohydrodynamic lubrication of line contacts

    NASA Technical Reports Server (NTRS)

    Ghosh, M. K.; Hamrock, B. J.

    1983-01-01

    A numerical solution to the problem of thermal elastohydrodynamic lubrication of line contacts was obtained by using a finite difference formulation. The solution procedure consists of simultaneous solution of the thermal Reynolds equation, the elasticity equation, and the energy equation subject to appropriate boundary conditions. Pressure distribution, film shape, and temperature distribution were obtained for fully flooded conjunctions, a paraffinic lubricant, and various dimensionless speed parameters while the dimensionless load and materials parameters were held constant. Reduction in the minimum film thickness due to thermal effects (as a ratio of thermal to isothermal minimum film thickness) is given by a simple formula as a function of the thermal loading parameter Q: H(min)/H(min,I) = 10/10+ Q(0.4). Plots of pressure distribution, film shape, temperature distribution, and flow are shown for some representative cases.

  9. Experience with synthetic fluorinated fluid lubricants

    NASA Technical Reports Server (NTRS)

    Conley, Peter L.; Bohner, John J.

    1990-01-01

    Since the late 1970's, the wet lubricant of choice for space mechanisms has been one of the family of synthetic perfluoro polyalkylether (PFPE) compounds, namely Fomblin Z-25 (Bray-815Z) or DuPont's Krytox 143xx series. While offering the advantages of extremely low vapor pressures and wide temperature ranges, these oils and derived greases have a complex chemistry compared to the more familiar natural and synthetic hydrocarbons. Many aerospace companies have conducted test programs to characterize the behavior of these compounds in a space environment, resulting in a large body of hard knowledge as well as considerable space lore concerning the suitability of the lubricants for particular applications and techniques for successful application. The facts are summarized and a few myths about the compounds are dispelled, and some performance guidelines for the mechanism design engineer are provided.

  10. Characteristics of wax extracted from lubricant basestocks

    SciTech Connect

    Guzauskas, J.F.; Abbott, F.P.; Baumgartner, N.R.

    1994-04-01

    This report describes a process for characterizing wax extracted from lubricant basestocks. The authors chose seven basestocks coming from different global regions and having a wide range of low-temperature properties. The wax was extracted from each basestock at-40{degrees}C using a cold-filtering method. Gas chromatography/mass spectroscopy (GC/MS), differential scanning calorimetry (DSC), thermal mechanical analysis (TMA), and optical microscopy (OM) were used to characterize these waxes. These data were compared to each basestock/s viscosity, pour point, and borderline pumping temperature, and some correlations were found between the wax characteristics and the cold temperature properties of the basestocks. This method of characterization can be useful when trying to select the optimal pour point depressant for engine lubricants. 10 refs., 24 figs., 5 tabs.

  11. Water lubricates hydrogen-bonded molecular machines

    NASA Astrophysics Data System (ADS)

    Panman, Matthijs R.; Bakker, Bert H.; den Uyl, David; Kay, Euan R.; Leigh, David A.; Buma, Wybren Jan; Brouwer, Albert M.; Geenevasen, Jan A. J.; Woutersen, Sander

    2013-11-01

    The mechanical behaviour of molecular machines differs greatly from that of their macroscopic counterparts. This applies particularly when considering concepts such as friction and lubrication, which are key to optimizing the operation of macroscopic machinery. Here, using time-resolved vibrational spectroscopy and NMR-lineshape analysis, we show that for molecular machinery consisting of hydrogen-bonded components the relative motion of the components is accelerated strongly by adding small amounts of water. The translation of a macrocycle along a thread and the rotation of a molecular wheel around an axle both accelerate significantly on the addition of water, whereas other protic liquids have much weaker or opposite effects. We tentatively assign the superior accelerating effect of water to its ability to form a three-dimensional hydrogen-bond network between the moving parts of the molecular machine. These results may indicate a more general phenomenon that helps explain the function of water as the ‘lubricant of life’.

  12. Water lubricates hydrogen-bonded molecular machines.

    PubMed

    Panman, Matthijs R; Bakker, Bert H; den Uyl, David; Kay, Euan R; Leigh, David A; Buma, Wybren Jan; Brouwer, Albert M; Geenevasen, Jan A J; Woutersen, Sander

    2013-11-01

    The mechanical behaviour of molecular machines differs greatly from that of their macroscopic counterparts. This applies particularly when considering concepts such as friction and lubrication, which are key to optimizing the operation of macroscopic machinery. Here, using time-resolved vibrational spectroscopy and NMR-lineshape analysis, we show that for molecular machinery consisting of hydrogen-bonded components the relative motion of the components is accelerated strongly by adding small amounts of water. The translation of a macrocycle along a thread and the rotation of a molecular wheel around an axle both accelerate significantly on the addition of water, whereas other protic liquids have much weaker or opposite effects. We tentatively assign the superior accelerating effect of water to its ability to form a three-dimensional hydrogen-bond network between the moving parts of the molecular machine. These results may indicate a more general phenomenon that helps explain the function of water as the 'lubricant of life'.

  13. High temperature lubricant screening and systems studies

    NASA Technical Reports Server (NTRS)

    Jones, D. A.

    1973-01-01

    Four candidate lubricants for next generation aircraft gas turbine application were tested under open atmosphere conditions in a rig simulating an advanced engine 125 mm bore mainshaft thrust bearing position. Testing was conducted at speeds to 24,000 rpm (3,000,000 bearing DN), bearing ring temperature of 500 F, and with 1200 F air and 100 psi differential pressure across the seals installed in a dual tandem arrangement. Test bearing was a 125 mm bore split inner ring, outer race riding angular contact ball bearing under a 3280 lb. thrust load. One lubricant, a type 2 ester, performed extremely well. The mainshaft seal limited the performance. Numerous design improvements for this seal were indicated.

  14. Lubrication at Physiological Pressures by Polyzwitterionic Brushes

    NASA Astrophysics Data System (ADS)

    Chen, Meng; Briscoe, Wuge H.; Armes, Steven P.; Klein, Jacob

    2009-03-01

    The very low sliding friction at natural synovial joints, which have friction coefficients of μ < 0.002 at pressures up to 5 megapascals or more, has to date not been attained in any human-made joints or between model surfaces in aqueous environments. We found that surfaces in water bearing polyzwitterionic brushes that were polymerized directly from the surface can have μ values as low as 0.0004 at pressures as high as 7.5 megapascals. This extreme lubrication is attributed primarily to the strong hydration of the phosphorylcholine-like monomers that make up the robustly attached brushes, and may have relevance to a wide range of human-made aqueous lubrication situations.

  15. Thermohydrodynamic analysis for laminar lubricating films

    NASA Technical Reports Server (NTRS)

    Elrod, H. G.; Brewe, D. E.

    1986-01-01

    A Galerkin-type analysis to include thermal effects in laminar lubricating films was performed. The lubricant properties were assumed constant except for a temperature-dependent Newtonian viscosity. The cross-film temperature profile is established by collocation at the film boundaries and two interior Lobatto points. The interior temperatures are determined by requiring that the zeroth and first moment of the energy equation be satisfied across the film. The fluidity is forced to conform to a third--degree polynomial appropriate to the Lobatto-point temperatures. Preliminary indications are that the use of just two such sampling points enables satisfactory prediction of bearing performance even in the presence of substantial viscosity variation.

  16. Application of Carbon Based Nano-Materials to Aeronautics and Space Lubrication

    NASA Technical Reports Server (NTRS)

    Street, Kenneth W., Jr.; Miyoshi, Kazuhisa; Wal, Randy L. Vander

    2007-01-01

    The tribology program at NASA Glenn Research Center in Cleveland, Ohio, is investigating carbon based nano-particles for their potential in advanced concept lubrication products. Service conditions range from high temperature atmospheric to low temperature vacuum. Some of the lubricants and surface coatings of tribological significance that we have evaluated include neat nano-particles, both grown in-situ and as bulk material deposited on the substrate, and nano-particles dispersed in oils which are all highly substrate interactive. We discuss results of testing these systems in a spiral orbit tribometer (SOT) and a unidirectional pin-on-disc (PoD) tribometer. A nano-onions/Krytox mixture evaluated as a lubricant for angular contact bearings in air caused a marked lowering of the coefficient of friction (CoF) (0.04 to 0.05) for the mixture with an eight-fold improvement in lifetime over that of the Krytox alone. In vacuum, no effect was observed from the nano-onions. Multi-walled nanotubes (MWNT) and graphitized MWNT were tested under sliding friction in both air and vacuum. The MWNT which were grown in-situ oriented normal to the sliding surface exhibited low CoF (0.04) and long wear lives. Bulk MWNT also generate low CoF (0.01 to 0.04, vacuum; and 0.06, air) and long wear life (>1 million orbits, vacuum; and >3.5 million, air). Dispersed graphitized MWNT were superior to MWNT and both were superior to aligned MWNT indicating that orientation is not an issue for solid lubrication. Single-walled nanotubes (SWNT) were modified by cutting into shorter segments and by fluorination. All SWNTs exhibited low CoF in air, with good wear lives. The SWNT with slight fluorination yielded an ultra-low CoF of 0.002 although the best wear life was attributed to the nascent SWNT.

  17. Application of Thioether for Vapor Phase Lubrication

    NASA Technical Reports Server (NTRS)

    Graham, E. Earl

    1997-01-01

    The objective of these studies was to identify the optimal conditions for vapor phase lubrication using Thioether for both sliding and rolling wear. The important variable include; (1) The component materials including M50 steel, monel and silicon nitride. (2) The vapor concentration and flow rate. (3) The temperature in the range of 600 F to 1500 F. (4) The loads and rolling and/or sliding speeds.

  18. Evaluation of newly formulated Dow Corning 321 dry film lubricant

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    An evaluation of the newly formulated Dow Corning 321 dry film lubricant was performed. The purpose of the evaluation was to compare lubricating characteristics of Dow Corning 321 (STW4-2955, SCN No. 3) to those of Molykote 321R (STW4-2955). Ten igniter bolts were installed and torqued on test plates using the old formulation thread lubricant (Molykote 321R), and 10 bolts were installed using the new formulation (Dow Corning 321). After bolt removal, no signs of galling were found on any of the bolts or test plates threaded holes. Average torque-load values for each formulation were very close. Test results showed there are no significant differences in lubrication abilities between Molykote 321R and Dow Corning 321. It is recommended that, once current supplies of Molykote 321R are depleted, Dow Corning 321 dry film lubricant be used in place of Molykote 321R as a thread lubricant on redesigned solid rocket motor assemblies.

  19. Characterization of Spray Lubricants for the Die Casting Process

    SciTech Connect

    Sabau, Adrian S

    2008-01-01

    During the die casting process, lubricants are sprayed in order to cool the dies and facilitate the ejection of the casting. The cooling effects of the die lubricant were investigated using Thermogravimetric analysis (TGA), heat flux sensors (HFS), and infrared imaging. The evolution of the heat flux and pictures taken using a high speed infrared camera revealed that lubricant application was a transient process. The short time response of the HFS allows the monitoring and data acquisition of the surface temperature and heat flux without additional data processing. A similar set of experiments was performed with deionized water in order to assess the lubricant effect. The high heat flux obtained at 300 C was attributed to the wetting and absorbant properties of the lubricant. Pictures of the spray cone and lubricant flow on the die were also used to explain the heat flux evolution.

  20. Powder-lubricated piston ring development. Final report

    SciTech Connect

    Heshmat, H.

    1991-06-01

    The overall objective of this program was to demonstrate the feasibility of a new particulate lubrication concept for reducing piston ring/cylinder liner wear in coal-water slurry-fueled diesels by replacing the present oil-lubricated system with powder lubrication that would utilize coal ash, either alone or in combination with another powder. The feasibility of this particular lubrication concept for reducing ring/liner wear was demonstrated in a series of experiments utilizing redesigned and properly selected components. Wear performance for suitable ring/liner materials lubricated with a powder that incorporates the abrasive ash particles was evaluated in terms of load capacity, friction, and rate of wear for the best combination of ring design, ring and liner materials, and powder constituents. In addition, the use of a powder-lubricated system in the upper portion of the cylinder isolated the particulates from the lower portions of the engine, thus further reducing engine wear. (VC)

  1. Fire-retardant lubricant for turbine generators. Final report. [PWR

    SciTech Connect

    Pankowiecki, J.

    1983-01-01

    The use of a fire resistant fluid in steam turbine generator lubrication systems would reduce the fire risks associated with current mineral lubricating oils. This project was directed toward determining the fesibility of modifying an existing Westinghouse lubrication system to use a phosphate ester lubricating fluid. The effects of the fluid on major components of the lubrication system including oil supply system, bearings, and generator hydrogen seal system were investigated. Performance and material compatibility impact on system components are identified and modifications recommended where required. Estimates of major modification costs are presented. The results of this study indicate that, with appropriate system modifications, a phosphate ester fluid can be an effective and reliable steam turbine generator lubricant. Recommendations are presented for component verification testing.

  2. Determination of thin hydrodynamic lubricating film thickness using dichromatic interferometry.

    PubMed

    Guo, L; Wong, P L; Guo, F; Liu, H C

    2014-09-10

    This paper introduces the application of dichromatic interferometry for the study of hydrodynamic lubrication. In conventional methods, two beams with different colors are projected consecutively on a static object. By contrast, the current method deals with hydrodynamic lubricated contacts under running conditions and two lasers with different colors are projected simultaneously to form interference images. Dichromatic interferometry incorporates the advantages of monochromatic and chromatic interferometry, which are widely used in lubrication research. This new approach was evaluated statically and dynamically by measuring the inclination of static wedge films and the thickness of the hydrodynamic lubricating film under running conditions, respectively. Results show that dichromatic interferometry can facilitate real-time determination of lubricating film thickness and is well suited for the study of transient or dynamic lubricating problems. PMID:25321689

  3. Electrotunable Lubricity with Ionic Liquid Nanoscale Films

    PubMed Central

    Fajardo, O. Y.; Bresme, F.; Kornyshev, A. A.; Urbakh, M.

    2015-01-01

    One of the main challenges in tribology is finding the way for an in situ control of friction without changing the lubricant. One of the ways for such control is via the application of electric fields. In this respect a promising new class of lubricants is ionic liquids, which are solvent-free electrolytes, and their properties should be most strongly affected by applied voltage. Based on a minimal physical model, our study elucidates the connection between the voltage effect on the structure of the ionic liquid layers and their lubricating properties. It reveals two mechanisms of variation of the friction force with the surface charge density, consistent with recent AFM measurements, namely via the (i) charge effect on normal and in-plane ordering in the film and (ii) swapping between anion and cation layers at the surfaces. We formulate conditions that would warrant low friction coefficients and prevent wear by resisting “squeezing-out” of the liquid under compression. These results give a background for controllable variation of friction. PMID:25572127

  4. Optical microsystem for analyzing engine lubricants

    NASA Astrophysics Data System (ADS)

    Scott, Andrew J.; Mabesa, Jose R., Jr.; Gorsich, David; Rathgeb, Brian; Said, Ali A.; Dugan, Mark; Haddock, Tom F.; Bado, Philippe W.

    2004-12-01

    It is possible to dramatically improve the performance, reliability, and maintainability of vehicles and other similarly complex equipment if improved sensing and diagnostics systems are available. Each year military and commercial maintenance personnel unnecessarily replace, at scheduled intervals, significant amounts of lubricant fluids in vehicles, weapon systems, and supporting equipment. Personnel draw samples of fluids and send them to test labs for analysis to determine if replacement is necessary. Systematic use of either on-board (embedded) lubricant quality analysis capabilities will save millions of dollars each year in avoided fluid changes, saved labor, prevented damage to mechanical components while providing associated environmental benefits. This paper discusses the design, the manufacturing, and the evaluation of robust optical sensors designed to monitor the condition of industrial fluids. The sensors reported are manufactured from bulk fused silica substrates. They incorporate three-dimensional micro fluidic circuitry side-by-side with three-dimensional wave guided optical networks. The manufacturing of the optical waveguides are completed using a direct-write process based on the use of femtosecond laser pulses to locally alter the structure of the glass substrate at the nano-level. The microfluidic circuitry is produced using the same femtosecond laser based process, followed by an anisotropic wet chemical etching step. Data will be presented regarding the use of these sensors to monitor the quality of engine oil and possibly some other vehicle lubricants such as hydraulic oil.

  5. Normal and Shear Interactions between Hyaluronan–Aggrecan Complexes Mimicking Possible Boundary Lubricants in Articular Cartilage in Synovial Joints

    PubMed Central

    2012-01-01

    Using a surface force balance, normal and shear interactions have been measured between two atomically smooth surfaces coated with hyaluronan (HA), and with HA/aggrecan (Agg) complexes stabilized by cartilage link protein (LP). Such HA/Agg/LP complexes are the most abundant mobile macromolecular species permeating articular cartilage in synovial joints and have been conjectured to be present as boundary lubricants at its surface. The aim of the present study is to gain insight into the extremely efficient lubrication when two cartilage surfaces slide past each other in healthy joints, and in particular to elucidate the possible role in this of the HA/Agg/LP complexes. Within the range of our parameters, our results reveal that the HA/Agg/LP macromolecular surface complexes are much better boundary lubricants than HA alone, likely because of the higher level of hydration, due to the higher charge density, of the HA/Agg/LP layers with respect to the HA alone. However, the friction coefficients (μ) associated with the mutual interactions and sliding of opposing HA/Agg/LP layers (μ ≈ 0.01 up to pressure P of ca. 12 atm, increasing sharply at higher P) suggest that such complexes by themselves cannot account for the remarkable boundary lubrication observed in mammalian joints (up to P > 50 atm). PMID:23074968

  6. Mechanisms of lubrication and wear of a bonded solid-lubricant film

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1980-01-01

    The tribological properties of polyimide-bonded graphite fluoride films were investigated. A pin-on-disk type of testing apparatus was used; in addition to sliding a hemispherically tipped rider, a rider with a 0.95-mm-diameter flat area was slid against the film so that a lower, less variable contact stress could be achieved. Two stages of lubrication occurred: in the first, the film supported the load and the lubricating mechanism consisted of the shear of a thin surface layer between the rider and the bulk of the film. The second occurred after the bonded film had worn to the substrate, and consisted of the shear of very thin lubricant films between the rider and flat plateaus generated on the metallic substrate asperities. The film wear mechanism was strongly dependent on contact stress.

  7. The effect of vaginal lubricants on sperm motility in vitro.

    PubMed

    Goldenberg, R L; White, R

    1975-09-01

    Apart from the documentation of the spermicidal effects of KY Jelly and Surgilube, little information about the effect of vaginal lubricants on sperm motility has been available. Fifteen substances utilizable as vaginal lubricants were therefore tested for their effect on sperm motility in vitro. Petroleum jelly and glycerin had minimal detrimental effects on motility and apparently are the lubricants of choice when an infertility problem exists.

  8. Compatibility of refrigerants and lubricants with motor materials

    SciTech Connect

    Doerr, R.; Kujak, S.; Waite, T. )

    1993-01-01

    Equipment manufacturers are challenged to replace CFC-based refrigerants and their lubricants with environmentally acceptable alternatives. Information on the compatibility of motor materials with these alternative refrigerants and lubricants is a basic requirement for reliable performance. This report presents compatibility data for 24 commercially used motor materials exposed to 17 refrigerant/lubricant combinations. This compatibility data will enable the phase out of CFC's to continue at its current fast pace and insure the continued reliable performance of refrigerant-based equipment.

  9. Short and long time drop dynamics on lubricated substrates

    NASA Astrophysics Data System (ADS)

    Carlson, A.; Kim, P.; Amberg, G.; Stone, H. A.

    2013-11-01

    Liquid infiltrated solids have been proposed as functional solvent-phobic surfaces for handling single and multiphase flows. Implementation of such surfaces alters the interfacial transport phenomenon as compared to a dry substrate. To better understand the interface characteristics in such systems we study experimentally the dynamics of a pendant water drop in air that contacts a substrate coated by thin oil films. At short times the water drop is deformed by the oil that spreads onto the water-air interface, and the dynamics are characterized by inertial and viscous regimes. At late times, the the oil film under the drop relaxes either to a stable thin film or ruptures. In the thin film rupture regime, we measure the waiting time for the rupture as a function of the drop equilibrium contact angle on a dry substrate and the initial film height. The waiting time is rationalized by lubrication theory, which indicates that long-range intermolecular forces destabilize the oil-water interface and is the primary mechanism for the film drainage.

  10. MISCIBILITY, SOLUBILITY, AND VISCOSITY MEASUREMENTS FOR R-236EA WITH POTENTIAL LUBRICANTS

    EPA Science Inventory

    The report gives results of miscibility, solubility, and viscosity measurements of refrigerant R-236ea with three potential lubricants. (NOTE: The data were needed to determine the suitability of refrigerant/lubricant combinations for use in refrigeration systems.) The lubricants...

  11. Lubricant base stock potential of chemically modified vegetable oils.

    PubMed

    Erhan, Sevim Z; Sharma, Brajendra K; Liu, Zengshe; Adhvaryu, Atanu

    2008-10-01

    The environment must be protected against pollution caused by lubricants based on petroleum oils. The pollution problem is so severe that approximately 50% of all lubricants sold worldwide end up in the environment via volatility, spills, or total loss applications. This threat to the environment can be avoided by either preventing undesirable losses, reclaiming and recycling mineral oil lubricants, or using environmentally friendly lubricants. Vegetable oils are recognized as rapidly biodegradable and are thus promising candidates as base fluids in environment friendly lubricants. Lubricants based on vegetable oils display excellent tribological properties, high viscosity indices, and flash points. To compete with mineral-oil-based lubricants, some of their inherent disadvantages, such as poor oxidation and low-temperature stability, must be corrected. One way to address these problems is chemical modification of vegetable oils at the sites of unsaturation. After a one-step chemical modification, the chemically modified soybean oil derivatives were studied for thermo-oxidative stability using pressurized differential scanning calorimetry and a thin-film micro-oxidation test, low-temperature fluid properties using pour-point measurements, and friction-wear properties using four-ball and ball-on-disk configurations. The lubricants formulated with chemically modified soybean oil derivatives exhibit superior low-temperature flow properties, improved thermo-oxidative stability, and better friction and wear properties. The chemically modified soybean oil derivatives having diester substitution at the sites of unsaturation have potential in the formulation of industrial lubricants.

  12. Polyol esters as HFC-134a compressor lubricants

    SciTech Connect

    Komatsuzaki, S.; Homma, Y.; Itoh, Y.

    1994-10-01

    A polyol ester-based lubricant has been applied to HFC-134a household refrigerator compressors, because of its good miscibility with HFC-134a refrigerant, and there is a possibility that it will be applied to automobile air conditions. For better performance, further improvements are needed regarding miscibility, lubricity and chemical stability of the lubricant, because such systems are often used under extreme conditions. This report discusses the required properties and ways to improve performance of polyol esters as HFC-134a compressor lubricants. 7 refs., 14 figs., 4 tabs.

  13. Two methodologies for optical analysis of contaminated engine lubricants

    NASA Astrophysics Data System (ADS)

    Aghayan, Hamid; Bordatchev, Evgueni; Yang, Jun

    2012-01-01

    The performance, efficiency and lifetime of modern combustion engines significantly depend on the quality of the engine lubricants. However, contaminants, such as gasoline, moisture, coolant and wear particles, reduce the life of engine mechanical components and lubricant quality. Therefore, direct and indirect measurements of engine lubricant properties, such as physical-mechanical, electro-magnetic, chemical and optical properties, are intensively utilized in engine condition monitoring systems and sensors developed within the last decade. Such sensors for the measurement of engine lubricant properties can be used to detect a functional limit of the in-use lubricant, increase drain interval and reduce the environmental impact. This paper proposes two new methodologies for the quantitative and qualitative analysis of the presence of contaminants in the engine lubricants. The methodologies are based on optical analysis of the distortion effect when an object image is obtained through a thin random optical medium (e.g. engine lubricant). The novelty of the proposed methodologies is in the introduction of an object with a known periodic shape behind a thin film of the contaminated lubricant. In this case, an acquired image represents a combined lubricant-object optical appearance, where an a priori known periodic structure of the object is distorted by a contaminated lubricant. In the object shape-based optical analysis, several parameters of an acquired optical image, such as the gray scale intensity of lubricant and object, shape width at object and lubricant levels, object relative intensity and width non-uniformity coefficient are newly proposed. Variations in the contaminant concentration and use of different contaminants lead to the changes of these parameters measured on-line. In the statistical optical analysis methodology, statistical auto- and cross-characteristics (e.g. auto- and cross-correlation functions, auto- and cross-spectrums, transfer function

  14. Lubricants for HFC-134a Compatible Rotary Compressors

    NASA Astrophysics Data System (ADS)

    Takaichi, Kenji; Sakai, Hisakazu

    In replacing CFC-12 with HFC-134a for refrigerator compressors, the compatibility with lubricating oil, and lubrication in general, are of major concern. HFC-134a dose not have adequate solubility with current lubricating oils because of its molecular structure. Current oils also do not provide enough lubricating action when using HFC-134a. A new oil and new materials have to be utilized in order to use HFC-134a. Developing a new lubricating oil involved numerous tests of different combinations of many polyolester synthetic oils and additives. One of the pre-evaluated methods was pursued via sealed tube tests. Lubricated parts were selected by studies involving a plane-on-roller type of wear test machine and by analyzing the traces of acid material commonly created during the lubricating action. The matrices of new lubricating oils and new lubricated materials were estimated based on durability tests conducted on compressors and refrigerators. Results showed that polyolester synthetic oils having a low total acid value and including certain quantities of additives did not break down into a tar-like substance and they did not produce composite particles in the operating compressors and refrigerators. The study also found that ceramics and anti-corrosion alloy steel possessed good adrasion-reducing qualities. Based on our evaluation, we will implement compressor reliability tests and apply HFC-134a to rotary compressors for refrigerators.

  15. On the transition from boundary lubrication to hydrodynamic lubrication in soft contacts.

    PubMed

    Persson, B N J; Scaraggi, M

    2009-05-01

    We consider the contact between elastically soft solids with randomly rough surfaces in sliding contact in a fluid, which is assumed to be Newtonian with constant (pressure-independent) viscosity. We discuss the nature of the transition from boundary lubrication at low sliding velocity, where direct solid-solid contact occurs, to hydrodynamic lubrication at high sliding velocity, where the solids are separated by a thin fluid film. We consider both hydrophilic and hydrophobic systems, and cylinder-on-flat and sphere-on-flat sliding configurations. We show that, for elastically soft solids such as rubber, including cavitation or not results in nearly the same friction.

  16. Tribological properties of PM212: A high-temperature, self-lubricating, powder metallurgy composite

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.

    1989-01-01

    This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

  17. Tribological properties of PM212 - A high temperature, self-lubricating, powder metallurgy composite

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.

    1990-01-01

    This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

  18. Aluminide coatings

    SciTech Connect

    Henager, Jr; Charles, H; Shin, Yongsoon; Samuels, William D

    2009-08-18

    Disclosed herein are aluminide coatings. In one embodiment coatings are used as a barrier coating to protect a metal substrate, such as a steel or a superalloy, from various chemical environments, including oxidizing, reducing and/or sulfidizing conditions. In addition, the disclosed coatings can be used, for example, to prevent the substantial diffusion of various elements, such as chromium, at elevated service temperatures. Related methods for preparing protective coatings on metal substrates are also described.

  19. COATED ALLOYS

    DOEpatents

    Harman, C.G.; O'Bannon, L.S.

    1958-07-15

    A coating is described for iron group metals and alloys, that is particularly suitable for use with nickel containing alloys. The coating is glassy in nature and consists of a mixture containing an alkali metal oxide, strontium oxide, and silicon oxide. When the glass coated nickel base metal is"fired'' at less than the melting point of the coating, it appears the nlckel diffuses into the vitreous coating, thus providing a closely adherent and protective cladding.

  20. Full Life Wind Turbine Gearbox Lubricating Fluids

    SciTech Connect

    Lutz, Glenn A.; Jungk, Manfred; Bryant, Jonathan J.; Lauer, Rebecca S.; Chobot, Anthony; Mayer, Tyler; Palmer, Shane; Kauffman, Robert E.

    2012-02-28

    Industrial gear box lubricants typically are hydrocarbon based mineral oils with considerable amounts of additives to overcome the lack of base fluid properties like wear protection, oxidation stability, load carrying capacity, low temperature solidification and drop of viscosity at higher temperatures. For today's wind turbine gearboxes, the requirements are more severe and synthetic hydrocarbon oils are used to improve on this, but all such hydrocarbon based lubricants require significant amounts of Extreme Pressure (EP) additives to meet performance requirements. Perfluoropolyether (PFPE) fluids provide load carrying capacity as an inherent property. During the course of the project with the main tasks of 'Establish a Benchmark', 'Lubricant Evaluation', 'Full Scale Gearbox Trial' and 'Economic Evaluation', the PAO Reference oil exhibited significant changes after laboratory gear testing, in service operation in the field and full scale gearbox trial. Four hydrocarbon base oils were selected for comparison in the benchmarking exercise and showed variation with respect to meeting the requirements for the laboratory micro-pitting tests, while the PFPE fluid exceeded the requirements even with the material taken after the full scale gear box trial. This is remarkable for a lubricant without EP additives. Laboratory bearing tests performed on the PFPE fluids before and after the full scale gear box trial showed the results met requirements for the industry standard. The PFPE fluid successfully completed the full scale gear box test program which included baseline and progressive staged load testing. The evaluation of gears showed no micro-pitting or objectionable wear. By the final stage, lubricant film thickness had been reduced to just 21% of its original value, this was by design and resulted in a lambda ratio of well below 1. This test design scenario of a low lambda ratio is a very undesirable lubrication condition for real world but creates the ability to test