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Sample records for pvd dual magnetron

  1. Control of particle flux and energy on substrate in an inverted cylindrical magnetron for plasma PVD

    NASA Astrophysics Data System (ADS)

    Todoran, A.; Mantel, M.; Bés, A.; Vachey, C.; Lacoste, A.

    2014-12-01

    Inverted cylindrical magnetrons (ICMs) are often used in dc, pulsed dc or mid-frequency ac mode for coating complex objects with thin films deposited by plasma PVD. Since in such a configuration the substrate is inherently surrounded by the target and hence by the plasma, the energy flux of the impinging particles represents the main contribution to the substrate heating. This can readily constitute a limiting factor in the deposition process, especially when it is not possible to cool and bias the substrate. This work concerns a dc-driven ICM configuration subjected to several constraints: not only is the substrate surface area small by comparison to the cathode surface area, but its imposed potential is the ground one, thus itself constituting the anode surface of the considered setup. Several important substrate heating factors are highlighted and, in order to reduce the most prominent of them, a means to raise the plasma potential is proposed. This is achieved by positively polarizing two additional electrodes with respect to the ground. This additional surface generates a redistribution of the current and consequently regulates the electron flux on the substrate. The results are shown as a function of bias applied on the auxiliary electrodes and discussed in terms of the impact on the substrate heating.

  2. Preparation of a-SiC:H/a-GeC:H superlattices by dual magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Saito, N.; Yamaguchi, T.

    1989-10-01

    Amorphous semiconductor superlattices composed of hydrogenated amorphous silicon carbon alloys and germanium carbon alloys have been prepared by a dual magnetron sputtering method. A small-angle x-ray diffraction measurement has indicated that the superlattices consist of well-defined smooth layers. Optical band gap has been examined for a series of samples; the thickness of the germanium carbon layer was changed from 20 to 130 Å, while the thickness of the silicon carbon layer was kept constant at 60 Å. The optical band gap increases upon decreasing the thickness of the germanium carbon layer, indicating quantum size effects due to the formation of superlattice structures.

  3. Effects of an unbalanced magnetron in a unique dual-cathode, high rate reactive sputtering system

    NASA Technical Reports Server (NTRS)

    Rohde, S. L.; Petrov, I.; Sproul, W. D.; Barnett, S. A.; Rudnik, P. J.; Graham, M. E.

    1990-01-01

    Simple plasma and magnetic field measurements are presented to illustrate the opportunities afforded by using unbalanced magnetrons in a dual-cathode system. The system employs a pair of opposed cathodes, 38 cm x 13 cm, placed 27.5 cm apart, to coat specimens mounted on a rotational substrate holder. Comparisons are drawn between the original 'balanced' magnetron and several unbalanced configurations in terms of field strengths, deposition rates, etching characteristics, and substrate ion current densities for the growth of TiN films. The effects of 'unbalancing' on the nature of the plasma within the 3D geometry of the deposition chamber are elucidated via plasma probe and magnetic field studies performed under a variety of conditions. All the unbalanced configurations examined provided enhanced ion bombardment at the surface of the growing film. The closed-field or opposed magnet geometry resulted in a threefold or greater increase in current density when compared with that obtained using the corresponding mirrored geometry under the same conditions.

  4. Development of Dual-Frequency Gyrotron with Triode Magnetron Injection Gun

    NASA Astrophysics Data System (ADS)

    Kajiwara, Ken; Oda, Yasuhisa; Kasugai, Atsushi; Takahashi, Koji; Sakamoto, Keishi

    2011-12-01

    A high power dual-frequency gyrotron is designed and tested. The design is based on a 170 GHz single-frequency gyrotron with a triode magnetron injection gun (MIG). The triode MIG enables to choose variety of oscillation modes for different frequencies with suitable pitch factor, which is the great advantage for a multi-frequency gyrotron. Another frequency of 137 GHz is selected in order to use a 1.853-mm-thick single-disk output window. Cavity modes are TE31,11 and TE25,9 for 170 and 137 GHz, respectively, which have high mode conversion efficiency to the RF beam mode with similar radiation angles. In short-pulse experiments, the maximum power of more than 1.3 MW is achieved with high-efficiency for both frequencies.

  5. Control of ions energy distribution in dual-frequency magnetron sputtering discharges

    SciTech Connect

    Ye, Chao He, Haijie; Huang, Fupei; Liu, Yi; Wang, Xiangying

    2014-04-15

    The ion energy distributions (IEDs) in the dual-frequency magnetron sputtering discharges were investigated by retarding field energy analyzer. Increasing power ratio of 2 MHz to 13.56 (27.12 or 60) MHz led to the evolution of IEDs from a uni-modal distribution towards a uni-modal distribution with high-energy peak shoulder and a bi-modal distribution. While increasing power ratio of 13.56 MHz to 27.12 MHz and 27.12 MHz to 60 MHz, led to the increase of peak energy. The evolution of IEDs shape and the increase of peak energy are due to the change of ions responding to the average field of high-frequency period towards the instantaneous sheath potential of low-frequency period.

  6. Physical properties of erbium implanted tungsten oxide filmsdeposited by reactive dual magnetron sputtering

    SciTech Connect

    Mohamed, Sodky H.; Anders, Andre

    2006-11-08

    Amorphous and partially crystalline WO3 thin films wereprepared by reactive dual magnetron sputtering and successively implantedby erbium ions with a fluence in the range from 7.7 x 1014 to 5 x 1015ions/cm2. The electrical and optical properties were studied as afunction of the film deposition parameters and the ion fluence. Ionimplantation caused a strong decrease of the resistivity, a moderatedecrease of the index of refraction and a moderate increase of theextinction coefficient in the visible and near infrared, while theoptical band gap remained almost unchanged. These effects could belargely ascribed to ion-induced oxygen deficiency. When annealed in air,the already low resistivities of the implanted samples decreased furtherup to 70oC, whereas oxidation, and hence a strong increase of theresistivity, was observed at higher annealing temperatures.

  7. Effect of ion bombarding energies on photocatalytic TiO{sub 2} films growing in a pulsed dual magnetron discharge

    SciTech Connect

    Novak, Ondrej; Vlcek, Jaroslav

    2011-05-15

    Photocatalytic crystalline TiO{sub 2} films were deposited by a pulsed dc dual magnetron system. The depositions were performed using two unbalanced magnetrons with planar titanium targets of 50 mm diameter in Ar+O{sub 2} gas mixtures at a total pressure of 0.9 Pa with oxygen partial pressures ranging from 0.2 to 0.9 Pa. The maximum substrate surface temperature was 160 deg. C Both magnetrons operated in the same asymmetric bipolar mode at the repetition frequencies of 100 and 350 kHz with a fixed 50% duty cycle and the average target power densities of 52-74 W cm{sup -2} in the negative voltage phase of the pulses, but the magnetron operations were shifted by a half of the period. Time-averaged energy-resolved mass spectroscopy was performed at a substrate position located 100 mm from the targets. The measured structure of the ion energy distributions was correlated with the distinct pulse phases of the magnetron discharges. A decrease in the energy delivered by fast ions (E{>=}10 eV) to the unit volume of the growing films, together with possible effects of plasma-chemical processes, during the depositions at the oxygen partial pressures of 0.5-0.75 Pa and the repetition frequency of 350 kHz resulted in a strong predominance of the highly photoactive crystalline anatase phase in the TiO{sub 2} films.

  8. Structural, optical and electrical properties of WOxNy filmsdeposited by reactive dual magnetron sputtering

    SciTech Connect

    Mohamed, Sodky H.; Anders, Andre

    2006-06-05

    Thin films of tungsten oxynitride were prepared by dual magnetron sputtering of tungsten using argon/oxygen/nitrogen gas mixtures with various nitrogen/oxygen ratios. The presence of even small amounts of oxygen had a great effect not only on the composition but on the structure of WOxNy films, as shown by Rutherford backscattering and x-ray diffraction, respectively. Significant incorporation of nitrogen occurred only when the nitrogen partial pressure exceeded 89 percent of the total reactive gas pressure. Sharp changes in the stoichiometry, deposition rate, room temperature resistivity, electrical activation energy and optical band gap were observed when the nitrogen/oxygen ratio was high.The deposition rate increased from 0.31 to 0.89 nm/s, the room temperature resistivity decreased from 1.65 x 108 to 1.82 x 10-2 ?cm, the electrical activation energy decreased from 0.97 to 0.067 eV, and the optical band gap decreased from 3.19 to 2.94 eV upon nitrogen incorporation into the films. WOxNy films were highly transparent as long as the nitrogen incorporation was low, and were brownish (absorbing) and partially reflecting as nitrogen incorporation became significant.

  9. Sputter deposition of MgxAlyOz thin films in a dual-magnetron device: a multi-species Monte Carlo model

    NASA Astrophysics Data System (ADS)

    Yusupov, M.; Saraiva, M.; Depla, D.; Bogaerts, A.

    2012-07-01

    A multi-species Monte Carlo (MC) model, combined with an analytical surface model, has been developed in order to investigate the general plasma processes occurring during the sputter deposition of complex oxide films in a dual-magnetron sputter deposition system. The important plasma species, such as electrons, Ar+ ions, fast Ar atoms and sputtered metal atoms (i.e. Mg and Al atoms) are described with the so-called multi-species MC model, whereas the deposition of MgxAlyOz films is treated by an analytical surface model. Target-substrate distances for both magnetrons in the dual-magnetron setup are varied for the purpose of growing stoichiometric complex oxide thin films. The metal atoms are sputtered from pure metallic targets, whereas the oxygen flux is only directed toward the substrate and is high enough to obtain fully oxidized thin films but low enough to avoid target poisoning. The calculations correspond to typical experimental conditions applied to grow these complex oxide films. In this paper, some calculation results are shown, such as the densities of various plasma species, their fluxes toward the targets and substrate, the deposition rates, as well as the film stoichiometry. Moreover, some results of the combined model are compared with experimental observations. Note that this is the first complete model, which can be applied for large and complicated magnetron reactor geometries, such as dual-magnetron configurations. With this model, we are able to describe all important plasma species as well as the deposition process. It can also be used to predict film stoichiometries of complex oxide films on the substrate.

  10. Effect of hafnium doping on density of states in dual-target magnetron co-sputtering HfZnSnO thin film transistors

    SciTech Connect

    Huang, Chuan-Xin; Li, Jun Fu, Yi-Zhou; Jiang, Xue-Yin; Zhang, Jian-Hua; Zhang, Zhi-Lin

    2015-11-23

    This study investigates the effect of hafnium doping on the density of states (DOSs) in HfZnSnO thin film transistors fabricated by dual-target magnetron co-sputtering system. The DOSs is extracted by temperature-dependent field-effect measurements, and they decrease from 1.1 × 10{sup 17} to 4.6 × 10{sup 16 }eV/cm{sup 3} with increasing the hafnium concentrations. The behavior of DOSs for the increasing hafnium concentration HfZnSnO thin film transistors can be confirmed by both the reduction of ΔV{sub T} under bias stress and the trapping charges calculated by capacitance voltage measurements. It suggests that the reduction in DOSs due to the hafnium doping is closely related with the bias stability and thermal stability.

  11. Parameter tuning of PVD process based on artificial intelligence technique

    NASA Astrophysics Data System (ADS)

    Norlina, M. S.; Diyana, M. S. Nor; Mazidah, P.; Rusop, M.

    2016-07-01

    In this study, an artificial intelligence technique is proposed to be implemented in the parameter tuning of a PVD process. Due to its previous adaptation in similar optimization problems, genetic algorithm (GA) is selected to optimize the parameter tuning of the RF magnetron sputtering process. The most optimized parameter combination obtained from GA's optimization result is expected to produce the desirable zinc oxide (ZnO) thin film from the sputtering process. The parameters involved in this study were RF power, deposition time and substrate temperature. The algorithm was tested to optimize the 25 datasets of parameter combinations. The results from the computational experiment were then compared with the actual result from the laboratory experiment. Based on the comparison, GA had shown that the algorithm was reliable to optimize the parameter combination before the parameter tuning could be done to the RF magnetron sputtering machine. In order to verify the result of GA, the algorithm was also been compared to other well known optimization algorithms, which were, particle swarm optimization (PSO) and gravitational search algorithm (GSA). The results had shown that GA was reliable in solving this RF magnetron sputtering process parameter tuning problem. GA had shown better accuracy in the optimization based on the fitness evaluation.

  12. Optical constants of silicon carbide deposited with emerging PVD techniques

    NASA Astrophysics Data System (ADS)

    Monaco, Gianni; Suman, M.; Pelizzo, M. G.; Nicolosi, P.

    2009-05-01

    Silicon carbide (SiC) is an attractive material for EUV and soft X-ray optics. CVD-deposited silicon carbide (deposited at 1400° C on Si substrate) is the best reflective material in the whole EUV interval (with about the 48% of reflectance at 121.6 nm). Despite of this, SiC thin films deposited with PVD techniques, such as magnetron sputtering, on silicon substrate, do not have the same performances and they undergo to a degradation with time, probably because of some stoichiometry reason (carbon rich). Depositing stable SiC with PVD techniques is crucial in building ML's, like Si/SiC and SiC/Mg for soft X-ray applications (such space telescope and photolithography). We deposited some preliminary samples using the Pulsed Laser Deposition (PLD) and the Pulsed Electron Deposition (PED) techniques achieving a good reflectance in the whole EUV range (27% at near normal incidence at 121.6 nn) on a silicon substrate. The higher energy involved in these deposition processes could lead to a film with a stoichiometry much closer to the target one. The reflectivity of the deposited films has been measured at the BEAR beamline of the ELETTRA synchrotron in Trieste (Italy; the optical constants retrieved at six wavelength from 121.6 nm down to 5 nm.

  13. Characterisation of Mg biodegradable stents produced by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Elmrabet, N.; Botterill, N.; Grant, D. M.; Brown, P. D.

    2015-10-01

    Novel Mg-minitubes for biodegradable stent applications have been produced using PVD magnetron sputtering. The minitubes were characterised, as a function of annealing temperature, using a combination of SEM/EDS, XRD and hardness testing. The as-deposited minitubes exhibited columnar grain structures with high levels of porosity. Slight alteration to the crystal structure from columnar to equiaxed grain growth was demonstrated at elevated temperature, along with increased material densification, hardness and corrosion resistance.

  14. Lutetium Oxide Coatings by PVD

    PubMed Central

    Topping, Stephen G; Park, CH; Rangan, SK; Sarin, VK

    2009-01-01

    Due to its high density and cubic structure, Lutetium oxide (Lu2O3) has been extensively researched for scintillating applications. Present manufacturing methods, such as hot pressing and sintering, do not provide adequate resolution due to light scattering of polycrystalline materials. Vapor deposition has been investigated as an alternative manufacturing method. Lutetium oxide transparent optical coatings by magnetron sputtering offer a means of tailoring the coating for optimum scintillation and resolution. Sputter deposited coatings typically have inherent stress and defects that adversely affect transparency and emission. The effect of process parameters on the coating properties is being investigated via x-ray diffraction (XRD), scanning electron microscopy (SEM) and emission spectroscopy, and will be presented and discussed. PMID:20390046

  15. ION MAGNETRON

    DOEpatents

    Gow, J.D.; Layman, R.W.

    1962-10-31

    A magnetohydrodynamic device or plasma generator of the ion magnetron class is described wherein a long central electrode is disposed along the axis of an evacuated cylinder. A radial electric field and an axial magnetic field are provided between the cylsnder and the electrode, forming a plasma trapping and heating region. For maximum effectiveness, neutral particles from the cylinder wall must be prevented from entering such region This is effected by forming a cylindrical sheath of electrons near the cylinder wall for ionizing undesired neutral particles, which are then trapped and removed by the magnetic field. An annular filament at one end of the device provides the electrons, which follow the axial magnetic field to a reflecting electrode at the opposite end of the device. (AEC)

  16. Membrane-association determinants of the omega-amino acid monooxygenase PvdA, a pyoverdine biosynthetic enzyme from Pseudomonas aeruginosa.

    PubMed

    Imperi, Francesco; Putignani, Lorenza; Tiburzi, Federica; Ambrosi, Cecilia; Cipollone, Rita; Ascenzi, Paolo; Visca, Paolo

    2008-09-01

    The L-ornithine N(delta)-oxygenase PvdA catalyses the N(delta)-hydroxylation of L-ornithine in many Pseudomonas spp., and thus provides an essential enzymic function in the biogenesis of the pyoverdine siderophore. Here, we report a detailed analysis of the membrane topology of the PvdA enzyme from the bacterial pathogen Pseudomonas aeruginosa. Membrane topogenic determinants of PvdA were identified by computational analysis, and verified in Escherichia coli by constructing a series of translational fusions between PvdA and the PhoA (alkaline phosphatase) reporter enzyme. The inferred topological model resembled a eukaryotic reverse signal-anchor (type III) protein, with a single N-terminal domain anchored to the inner membrane, and the bulk of the protein spanning the cytosol. According to this model, the predicted transmembrane region should overlap the putative FAD-binding site. Cell fractionation and proteinase K accessibility experiments in P. aeruginosa confirmed the membrane-bound nature of PvdA, but excluded the transmembrane topology of its N-terminal hydrophobic region. Mutational analysis of PvdA, and complementation assays in a P. aeruginosa DeltapvdA mutant, demonstrated the dual (structural and functional) role of the PvdA N-terminal domain. PMID:18757814

  17. PVD TBC experience on GE aircraft engines

    NASA Technical Reports Server (NTRS)

    Maricocchi, Antonio; Bartz, Andi; Wortman, David

    1995-01-01

    The higher performance levels of modern gas turbine engines present significant challenges in the reliability of materials in the turbine. The increased engine temperatures required to achieve the higher performance levels reduce the strength of the materials used in the turbine sections of the engine. Various forms of thermal barrier coatings (TBC's) have been used for many years to increase the reliability of gas turbine engine components. Recent experience with the physical vapor deposition (PVD) process using ceramic material has demonstrated success in extending the service life of turbine blades and nozzles. Engine test results of turbine components with a 125 micron (0.005 in) PVD TBC have demonstrated component operating temperatures of 56-83 C (100-150 F) lower than non-PVD TBC components. Engine testing has also revealed the TBC is susceptible to high angle particle impact damage. Sand particles and other engine debris impact the TBC surface at the leading edge of airfoils and fracture the PVD columns. As the impacting continues, the TBC erodes away in local areas. Analysis of the eroded areas has shown a slight increase in temperature over a fully coated area, however a significant temperature reduction was realized over an airfoil without TBC.

  18. PVD TBC experience on GE aircraft engines

    NASA Technical Reports Server (NTRS)

    Bartz, A.; Mariocchi, A.; Wortman, D. J.

    1995-01-01

    The higher performance levels of modern gas turbine engines present significant challenges in the reliability of materials in the turbine. The increased engine temperatures required to achieve the higher performance levels reduce the strength of the materials used in the turbine sections of the engine. Various forms of Thermal Barrier Coatings (TBC's) have been used for many years to increase the reliability of gas turbine engine components. Recent experience with the Physical Vapor Deposition (PVD) process using ceramic material has demonstrated success in extending the service life of turbine blades and nozzles. Engine test results of turbine components with a 125 micrometer (0.005 in) PVD TBC have demonstrated component operating temperatures of 56-83 C (100-150 F) lower than uncoated components. Engine testing has also revealed the TBC is susceptible to high angle particle impact damage. Sand particles and other engine debris impact the TBC surface at the leading edge of airfoils and fracture the PVD columns. As the impacting continues the TBC erodes away in local areas. Analysis of the eroded areas has shown a slight increase in temperature over a fully coated area, however, a significant temperature reduction was realized over an airfoil without any TBC.

  19. PVD TBC experience on GE aircraft engines

    NASA Astrophysics Data System (ADS)

    Maricocchi, A.; Bartz, A.; Wortman, D.

    1997-06-01

    The higher performance levels of modern gas turbine engines present significant challenges in the reli-ability of materials in the turbine. The increased engine temperatures required to achieve the higher per-formance levels reduce the strength of the materials used in the turbine sections of the engine. Various forms of thermal barrier coatings have been used for many years to increase the reliability of gas turbine engine components. Recent experience with the physical vapor deposition process using ceramic material has demonstrated success in extending the service life of turbine blades and nozzles. Engine test results of turbine components with a 125 μm (0.005 in.) PVD TBC have demonstrated component operating tem-peratures of 56 to 83 °C (100 to 150 °F) lower than non-PVD TBC components. Engine testing has also revealed that TBCs are susceptible to high angle particle impact damage. Sand particles and other engine debris impact the TBC surface at the leading edge of airfoils and fracture the PVD columns. As the impacting continues, the TBC erodes in local areas. Analysis of the eroded areas has shown a slight increase in temperature over a fully coated area ; however, a significant temperature reduc-tion was realized over an airfoil without TBC.

  20. Protection of yttria-stabilized zirconia for dental applications by oxidic PVD coating.

    PubMed

    Hübsch, C; Dellinger, P; Maier, H J; Stemme, F; Bruns, M; Stiesch, M; Borchers, L

    2015-01-01

    In this study, the application of transparent physical vapor deposition (PVD) coatings on zirconia ceramics was examined as an approach to retard the low-temperature degradation of zirconia for dental applications. Transparent monolayers of titanium oxide (TixOy) and multilayers consisting of titanium oxide-alumina-titanium oxide (TixOy-AlxOy-TixOy) were deposited onto standardized discs of 3Y-TZP using magnetron sputtering. Using X-ray photospectroscopy and time-of-flight secondary-ion mass spectrometry, the compositions of the coatings were verified, and an approximate thickness of 50 nm for each type of coating was ascertained. After aging the coated and uncoated samples in water vapor at 134°C and 3 bar for 4, 8, 16, 32, 64 and 128 h, the monoclinic phase content was determined using X-ray diffraction, and its impact on mechanical properties was assessed in biaxial flexural strength tests. In addition, the depth of the transformation zone was measured from scanning electron microscopy images of the fracture surfaces of hydrothermally aged samples. The results revealed that the tetragonal-to-monoclinic phase transformation of the zirconia ceramic was retarded by the application of PVD coatings. During the first stages of aging, the coated samples exhibited a significantly lower monoclinic phase content than the uncoated samples and, after 128 h of aging, showed a transformation zone which was only ∼12-15 μm thick compared to ∼30 μm in the control group. Biaxial flexural strength decreased by ∼10% during aging and was not influenced by the application of a PVD coating. PMID:25278443

  1. PVD Silicon Carbide as a Thin Film Packaging Technology for Antennas on LCP Substrates for Harsh Environments

    NASA Technical Reports Server (NTRS)

    Scardelletti, Maximilian C.; Stanton, John W.; Ponchak, George E.; Jordan, Jennifer L.; Zorman, Christian A.

    2010-01-01

    This paper describes an effort to develop a thin film packaging technology for microfabricated planar antennas on polymeric substrates based on silicon carbide (SiC) films deposited by physical vapor deposition (PVD). The antennas are coplanar waveguide fed dual frequency folded slot antennas fabricated on liquid crystal polymer (LCP) substrates. The PVD SiC thin films were deposited directly onto the antennas by RF sputtering at room temperature at a chamber pressure of 30 mTorr and a power level of 300 W. The SiC film thickness is 450 nm. The return loss and radiation patterns were measured before and after the SiC-coated antennas were submerged into perchloric acid for 1 hour. No degradation in RF performance or physical integrity of the antenna was observed.

  2. Magnetron sputtering source

    DOEpatents

    Makowiecki, D.M.; McKernan, M.A.; Grabner, R.F.; Ramsey, P.B.

    1994-08-02

    A magnetron sputtering source for sputtering coating substrates includes a high thermal conductivity electrically insulating ceramic and magnetically attached sputter target which can eliminate vacuum sealing and direct fluid cooling of the cathode assembly. The magnetron sputtering source design results in greater compactness, improved operating characteristics, greater versatility, and low fabrication cost. The design easily retrofits most sputtering apparatuses and provides for safe, easy, and cost effective target replacement, installation, and removal. 12 figs.

  3. Magnetron sputtering source

    DOEpatents

    Makowiecki, Daniel M.; McKernan, Mark A.; Grabner, R. Fred; Ramsey, Philip B.

    1994-01-01

    A magnetron sputtering source for sputtering coating substrates includes a high thermal conductivity electrically insulating ceramic and magnetically attached sputter target which can eliminate vacuum sealing and direct fluid cooling of the cathode assembly. The magnetron sputtering source design results in greater compactness, improved operating characteristics, greater versatility, and low fabrication cost. The design easily retrofits most sputtering apparatuses and provides for safe, easy, and cost effective target replacement, installation, and removal.

  4. Thermal stability of magnetron and ion beam sputtered top and bottom spin-valve films

    SciTech Connect

    Mao, Ming; Cerjan, Charlie; Hung, Stephanie; Miloslavsky, Lena; Chien, Chester; Sant, Sudhi

    2001-06-01

    The thermal stability of top and bottom IrMn exchange-biased spin-valve films prepared by ion beam deposition (IBD) and magnetron sputtering physical vapor deposition (PVD) is compared. These films exhibit identical temperature dependence for the exchange bias field H{sub ex}, with a blocking temperature of T{sub B}=250{degree}C, that is independent of preparation technique. Isothermal annealing at temperatures below T{sub B} led to a ln(t) dependent degradation in H{sub ex}, suggesting a thermal activation process. The high crystallographic quality of the IBD films leads to a superior stability compared to PVD films. Top spin-valve films are also found to be more stable than bottom spin-valve films. {copyright} 2001 American Institute of Physics.

  5. Thermal stability of magnetron and ion beam sputtered top and bottom spin-valve films

    NASA Astrophysics Data System (ADS)

    Mao, Ming; Cerjan, Charlie; Hung, Stephanie; Miloslavsky, Lena; Chien, Chester; Sant, Sudhi

    2001-06-01

    The thermal stability of top and bottom IrMn exchange-biased spin-valve films prepared by ion beam deposition (IBD) and magnetron sputtering physical vapor deposition (PVD) is compared. These films exhibit identical temperature dependence for the exchange bias field Hex, with a blocking temperature of TB=250 °C, that is independent of preparation technique. Isothermal annealing at temperatures below TB led to a ln(t) dependent degradation in Hex, suggesting a thermal activation process. The high crystallographic quality of the IBD films leads to a superior stability compared to PVD films. Top spin-valve films are also found to be more stable than bottom spin-valve films.

  6. Development and evaluation of two PVD-coated β-titanium orthodontic archwires for fluoride-induced corrosion protection.

    PubMed

    Krishnan, Vinod; Krishnan, Anand; Remya, R; Ravikumar, K K; Nair, S Asha; Shibli, S M A; Varma, H K; Sukumaran, K; Kumar, K Jyothindra

    2011-04-01

    The present research was aimed at developing surface coatings on β titanium orthodontic archwires capable of protection against fluoride-induced corrosion. Cathodic arc physical vapor deposition PVD (CA-PVD) and magnetron sputtering were utilized to deposit thin films of titanium aluminium nitride (TiAlN) and tungsten carbide/carbon (WC/C) coatings on β titanium orthodontic archwires. Uncoated and coated specimens were immersed in a high fluoride ion concentration mouth rinse, following a specially designed cycle simulating daily use. All specimens thus obtained were subjected to critical evaluation of parameters such as electrochemical corrosion behaviour, surface analysis, mechanical testing, microstructure, element release, and toxicology. The results confirm previous research that β titanium archwires undergo a degradation process when in contact with fluoride mouth rinses. The study confirmed the superior nature of the TiAlN coating, evident as many fewer changes in properties after fluoride treatment when compared with the WC/C coating. Thus, coating with TiAlN is recommended in order to reduce the corrosive effects of fluorides on β titanium orthodontic archwires. PMID:21111072

  7. Frequency agile relativistic magnetrons

    SciTech Connect

    Levine, J.S.; Harteneck, B.D.; Price, H.D.

    1995-11-01

    The authors are developing a family of frequency agile relativistic magnetrons to continuously cover the bands from 1 to 3 GHz. They have achieved tuning ranges of > 33%. The magnetrons have been operated repetitively in burst mode at rates up to 100 pps for 10 sec. Power is extracted from two resonators, and is in the range of 400--600 MW, fairly flat across the tuning bandwidth. They are using a network of phase shifters and 3-dB hybrids to combine the power into a single arm and to provide a continuously adjustable attenuator.

  8. Investigating the effect of Argon Pressure on DC and High Power Magnetron Plasmas

    NASA Astrophysics Data System (ADS)

    Bernales, Baysha; Bolat, Rustem; Anders, Andre; Slack, Jonathan; PAG Team; EETD Team

    2013-10-01

    Smart Glass is fabricated by depositing thin films of specialized material onto a transparent substrate. When a potential is applied across the surface of the Smart Glass, it changes its optical properties. Direct Current Magnetron Sputtering (DCMS) and High Power Impulse Magnetron Sputtering (HiPIMS) are two methods of PVD that are used to fabricate this material. In previous research, it has been noted that magnetron plasmas have localized ionization zones that rotate clockwise in DCMS and counterclockwise in HiPIMS. Not much is known about what causes the change in rotation. This research seeks to investigate what occurs during the first moments of plasma evolution. Both DC and high power magnetron plasmas were observed as Argon pressure was varied. It was found that pressure had a very pronounced effect on the floating-point potential signal that was received from the probes placed in the plasma. It was found that when a high-pressure jet of Argon was injected into the system, that the rotation pattern of the DC magnetron plasma was disrupted. It was also found that at certain pressures, the voltage signal was less indicative of azimuthal rotation and more indicative of z-direction breathing modes.

  9. Magnetron injection gun scaling

    SciTech Connect

    Lawson, W.

    1988-04-01

    Existing analytic design equations for magnetron injection guns (MIG's) are approximated to obtain a set of scaling laws. The constraints are chosen to examine the maximum peak power capabilities of MIG's. The scaling laws are compared with exact solutions of the design equations and are supported by MIG simulations.

  10. A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)

    SciTech Connect

    Anders, André

    2014-09-02

    In this study, high power impulse magnetron sputtering (HiPIMS) has been in the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come at a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in this review, an overview is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.

  11. A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)

    DOE PAGESBeta

    Anders, André

    2014-09-02

    In this study, high power impulse magnetron sputtering (HiPIMS) has been in the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come at a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in thismore » review, an overview is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.« less

  12. Magnetron sputtered boron films

    DOEpatents

    Makowiecki, Daniel M.; Jankowski, Alan F.

    1998-01-01

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence.

  13. Magnetron sputtered boron films

    DOEpatents

    Makowiecki, D.M.; Jankowski, A.F.

    1998-06-16

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence. 8 figs.

  14. A chemically stable PVD multilayer encapsulation for lithium microbatteries

    NASA Astrophysics Data System (ADS)

    Ribeiro, J. F.; Sousa, R.; Cunha, D. J.; Vieira, E. M. F.; Silva, M. M.; Dupont, L.; Goncalves, L. M.

    2015-10-01

    A multilayer physical vapour deposition (PVD) thin-film encapsulation method for lithium microbatteries is presented. Lithium microbatteries with a lithium cobalt oxide (LiCoO2) cathode, a lithium phosphorous oxynitride (LiPON) electrolyte and a metallic lithium anode are under development, using PVD deposition techniques. Metallic lithium film is still the most common anode on this battery technology; however, it presents a huge challenge in terms of material encapsulation (lithium reacts with almost any materials deposited on top and almost instantly begins oxidizing in contact with atmosphere). To prove the encapsulation concept and perform all the experiments, lithium films were deposited by thermal evaporation technique on top of a glass substrate, with previously patterned Al/Ti contacts. Three distinct materials, in a multilayer combination, were tested to prevent lithium from reacting with protection materials and atmosphere. These multilayer films were deposited by RF sputtering and were composed of lithium phosphorous oxide (LiPO), LiPON and silicon nitride (Si3N4). To complete the long-term encapsulation after breaking the vacuum, an epoxy was applied on top of the PVD multilayer. In order to evaluate oxidation state of lithium films, the lithium resistance was measured in a four probe setup (cancelling wires/contact resistances) and resistivity calculated, considering physical dimensions. A lithium resistivity of 0.16 Ω μm was maintained for more than a week. This PVD multilayer exonerates the use of chemical vapour deposition (CVD), glove-box chambers and sample manipulation between them, significantly reducing the fabrication cost, since battery and its encapsulation are fabricated in the same PVD chamber.

  15. A Hollow Cathode Magnetron (HCM)

    SciTech Connect

    S.A. Cohen; Z. Wang

    1998-04-01

    A new type of plasma sputtering device, named the hollow cathode magnetron (HCM), has been developed by surrounding a planar magnetron cathode with a hollow cathode structure (HCS). Operating characteristics of HCMs, current-voltage ( I-V ) curves for fixed discharge pressure and voltage-pressure ( V-p ) curves for fixed cathode current, are measured. Such characteristics are compared with their planar magnetron counterparts. New operation regimes, such as substantially lower pressures (0.3 mTorr), were discovered for HCMs. Cathode erosion profiles show marked improvement over planar magnetron in terms of material utilization. The use of HCMs for thin film deposition are discussed.

  16. Diffusion bonding of CMSX-4 to UDIMET 720 using PVD-coated interfaces and HIP

    SciTech Connect

    Larker, R.; Ockborn, J.; Selling, B.

    1999-07-01

    There is an increasing interest in development of manufacturing methods for Dual Property BLISKs (BLaded dISKs), consisting of creep resistant airfoils and fatigue resistant disks bonded together by a durable joint. Optimum heat treatments are, however, very different for creep resistant single crystal CMSX-4 and fatigue resistant polycrystalline Udimet 720 selected in this study, but fortunately the first aging treatment for CMSX-4 (1140 C, 2-6h, AC) is similar to the partial solution treatment of U 720 HS2 (1115 C, 4h, OQ). Based on this, diffusion bonding was performed by HIP at 1120 C and 200 MPa argon pressure for 4 h, followed by cooling to 400 C. Subsequently, a shortened Udimet 720 HS2 two-step aging treatment was adopted by heating to 650 C for 6 h followed by cooling to 400 C, heating to 760 C for 2 h, and finally cooling to R.T. under remaining HIP pressure. Plasma etching followed by thin (80 nm) PVD coating with either nickel or titanium were used to clean and protect the polished surfaces before joining. The selection of coatings was governed by the possibility to reduce oxidized nickel by flushing with hydrogen at 330 C during evacuation of the HIP capsules, and by the large solubility of oxygen in titanium. Hot tensile testing was performed at 750 C on both joined and reference materials subjected to the modified heat treatment. Initially solution treated Udimet 720 and CMSX-4 comprised the reference materials. The testing showed that joints with Ni-PV coatings were almost as strong as Udimet 720 (although with very limited elongation), while the joints with Ti-PVD coatings were weaker.

  17. Magic-T-Coupled Magnetrons

    NASA Technical Reports Server (NTRS)

    Dickinson, R. M.

    1985-01-01

    Outputs of two magnetrons added coherently in scheme based on resonant waveguide coupling and injection phase locking. In addition, filaments are turned off after starting. Overall effect is relatively-inexpensive, lowpower, noisy magnetrons generate clean carrier signals of higher power that ordinarily require more expensive klystrons.

  18. Magnetron tuner has locking feature

    NASA Technical Reports Server (NTRS)

    Martucci, V. J.

    1969-01-01

    Magnetron tuning arrangement features a means of moving a tuning ring axially within an anode cavity by a system of reduction gears engaging a threaded tuning shaft of lead screw. The shaft positions the tuning ring for the desired magnetron output frequency, and a washer prevents backlash.

  19. Structure and properties of PVD TiB{sub 2} coatings

    SciTech Connect

    Knotek, O.; Lugscheider, E.; Barimani, C.; Moeller, M.

    1997-10-01

    For optimizing machine parts about their function and lifetime not only the design has been varied but also the materials. Where moving parts are in contact with each other, mostly only a few nanometer thick layer guarantees the function. With surface coating by PVD the properties and structures of this layer can be modified, so the use of bulk material is not necessary. This study is about the development of a hard, wear resisting TiB{sub 2} coating for lubricant-free roller bearings. Therefore several pretensions must be fulfilled, for example, no change in the surface topography of the raceways and low temperature coating process for tempered materials. Consequently all coatings were done with the Magnetron sputter ion plating (MSIP) process. For the target material a hot isostatic pressed titanium diboride plate was used. This target is electrically conductive, so that the sputtering could be done with a dc plasma. Three different substrate materials were examined. These were tempered bearing steel (100 Cr 6), silicon nitride (Si{sub 3}N{sub 4}), and a cutting tool material (HS 6-5-2). For optimizing the coating process and adapting it to the different materials, the temperature and the bias voltage were varied. While Si{sub 3}N{sub 4} and HS 6-5-2 are insensitive to the coating temperature, the temperature of the tempered 100 Cr 6 must be lower than its tempering temperature otherwise a reduction in the hardness cannot be excluded and the support of the coating is not sufficient. The coatings were characterized by their microstructure and their mechanical properties.

  20. Recirculating Planar Magnetron Modeling and Experiments

    NASA Astrophysics Data System (ADS)

    Franzi, Matthew; Gilgenbach, Ronald; Hoff, Brad; French, Dave; Lau, Y. Y.

    2011-10-01

    We present simulations and initial experimental results of a new class of crossed field device: Recirculating Planar Magnetrons (RPM). Two geometries of RPM are being explored: 1) Dual planar-magnetrons connected by a recirculating section with axial magnetic field and transverse electric field, and 2) Planar cathode and anode-cavity rings with radial magnetic field and axial electric field. These RPMs have numerous advantages for high power microwave generation by virtue of larger area cathodes and anodes. The axial B-field RPM can be configured in either the conventional or inverted (faster startup) configuration. Two and three-dimensional EM PIC simulations show rapid electron spoke formation and microwave oscillation in pi-mode. Smoothbore prototype axial-B RPM experiments are underway using the MELBA accelerator at parameters of -300 kV, 1-20 kA and pulselengths of 0.5-1 microsecond. Implementation and operation of the first RPM slow wave structure, operating at 1GHz, will be discussed. Research supported by AFOSR, AFRL, L-3 Communications, and Northrop Grumman. Done...processed 1830 records...17:52:57 Beginning APS data extraction...17:52:57

  1. Nonsputtering impulse magnetron discharge

    SciTech Connect

    Khodachenko, G. V.; Mozgrin, D. V.; Fetisov, I. K.; Stepanova, T. V.

    2012-01-15

    Experiments with quasi-steady high-current discharges in crossed E Multiplication-Sign B fields in various gases (Ar, N{sub 2}, H{sub 2}, and SF{sub 6}) and gas mixtures (Ar/SF{sub 6} and Ar/O{sub 2}) at pressures from 10{sup -3} to 5 Torr in discharge systems with different configurations of electric and magnetic fields revealed a specific type of stable low-voltage discharge that does not transform into an arc. This type of discharge came to be known as a high-current diffuse discharge and, later, a nonsputtering impulse magnetron discharge. This paper presents results from experimental studies of the plasma parameters (the electron temperature, the plasma density, and the temperature of ions and atoms of the plasma-forming gas) of a high-current low-pressure diffuse discharge in crossed E Multiplication-Sign B fields.

  2. Double-sided Relativistic Magnetron

    NASA Astrophysics Data System (ADS)

    Agafonov, A. V.; Krastelev, E. G.

    1997-05-01

    A new scheme of a symmetricaly powered relativistic magnetron and several methods of localised electron flow forming in an interaction region are proposed to increase an efficiency of relativistic magnetrons. As will be shown, a very important reason is the effect of nonsymmetric feeding of power from one side of a magnetron, which is typical for experiments. One-sided powering leads to the axial drift of electrons, to the transformation of transverse velocities of electrons to longitudinal one and to the generation of a parasitic e-beam which does not take part in energy exchange between electrons and waves at all. A special driver was designed for double-sided powering of relativistic magnetrons. The proposed system is compact, rigid and capable of reliable operation at high repetition rates, which is advantageous for many applications. Several smooth-bore magnetrons were tested by means of computer simulations using PIC code KARAT. The results showed a dramatical difference between the dynamics of electron flow for one- and two-sided power feeding of a structure under test. Design of a driver and computer simulation results are presented.

  3. Nanocomposite metal amorphous-carbon thin films deposited by hybrid PVD and PECVD technique.

    PubMed

    Teixeira, V; Soares, P; Martins, A J; Carneiro, J; Cerqueira, F

    2009-07-01

    Carbon based films can combine the properties of solid lubricating graphite structure and hard diamond crystal structure, i.e., high hardness, chemical inertness, high thermal conductivity and optical transparency without the crystalline structure of diamond. Issues of fundamental importance associated with nanocarbon coatings are reducing stress, improving adhesion and compatibility with substrates. In this work new nanocomposite coatings with improved toughness based in nanocrystalline phases of metals and ceramics embedded in amorphous carbon matrix are being developed within the frame of a research project: nc-MeNxCy/a-C(Me) with Me = Mo, Si, Al, Ti, etc. Carbide forming metal/carbon (Me/C) composite films with Me = Mo, W or Ti possess appropriate properties to overcome the limitation of pure DLC films. These novel coating architectures will be adopted with the objective to decrease residual stress, improve adherence and fracture toughness, obtain low friction coefficient and high wear-resistance. Nanocomposite DLC's films were deposited by hybrid technique using a PVD-Physically Vapor Deposition (magnetron sputtering) and Plasma Enhanced Chemical Vapor Deposition (PECVD), by the use of CH4 gas. The parameters varied were: deposition time, substrate temperature (180 degrees C) and dopant (Si + Mo) of the amorphous carbon matrix. All the depositions were made on silicon wafers and steel substrates precoated with a silicon inter-layer. The characterisation of the film's physico-mechanical properties will be presented in order to understand the influence of the deposition parameters and metal content used within the a-C matrix in the thin film properties. Film microstructure and film hybridization state was characterized by Raman Spectroscopy. In order to characterize morphology SEM and AFM will be used. Film composition was measured by Energy-Dispersive X-ray analysis (EDS) and by X-ray photoelectron spectroscopy (XPS). The contact angle for the produced DLC's on

  4. Nanograined Net-Shaped Fabrication of Rhenium Components by EB-PVD

    NASA Astrophysics Data System (ADS)

    Singh, Jogender; Wolfe, Douglas E.

    2004-02-01

    Cost-effective net-shaped forming components have brought considerable interest into DoD, NASA and DoE. Electron beam physical vapor deposition (EB-PVD) offers flexibility in forming net-shaped components with tailored microstructure and chemistry. High purity rhenium (Re) components including rhenium-coated graphite balls, Re- plates and tubes have been successfully manufactured by EB-PVD. EB-PVD Re components exhibited sub-micron and nano-sized grains with high hardness and strength as compared to CVD. It is estimated that the cost of Re components manufactured by EB-PVD would be less than the current CVD and powder-HIP Technologies.

  5. Nanograined Net-Shaped Fabrication of Rhenium Components by EB-PVD

    SciTech Connect

    Singh, Jogender; Wolfe, Douglas E.

    2004-02-04

    Cost-effective net-shaped forming components have brought considerable interest into DoD, NASA and DoE. Electron beam physical vapor deposition (EB-PVD) offers flexibility in forming net-shaped components with tailored microstructure and chemistry. High purity rhenium (Re) components including rhenium-coated graphite balls, Re- plates and tubes have been successfully manufactured by EB-PVD. EB-PVD Re components exhibited sub-micron and nano-sized grains with high hardness and strength as compared to CVD. It is estimated that the cost of Re components manufactured by EB-PVD would be less than the current CVD and powder-HIP Technologies.

  6. Improved Thermal Cycling Durability of Thermal Barrier Coatings Manufactured by PS-PVD

    NASA Astrophysics Data System (ADS)

    Rezanka, S.; Mauer, G.; Vaßen, R.

    2014-01-01

    The plasma spray-physical vapor deposition (PS-PVD) process is a promising method to manufacture thermal barrier coatings (TBCs). It fills the gap between traditional thermal spray processes and electron beam physical vapor deposition (EB-PVD). The durability of PS-PVD manufactured columnar TBCs is strongly influenced by the compatibility of the metallic bondcoat (BC) and the ceramic TBC. Earlier investigations have shown that a smooth BC surface is beneficial for the durability during thermal cycling. Further improvements of the bonding between BC and TBC could be achieved by optimizing the formation of the thermally grown oxide (TGO) layer. In the present study, the parameters of pre-heating and deposition of the first coating layer were investigated in order to adjust the growth of the TGO. Finally, the durability of the PS-PVD coatings was improved while the main advantage of PS-PVD, i.e., much higher deposition rate in comparison to EB-PVD, could be maintained. For such coatings, improved thermal cycling lifetimes more than two times higher than conventionally sprayed TBCs, were measured in burner rigs at ~1250 °C/1050 °C surface/substrate exposure temperatures.

  7. Phase and Frequency Locked Magnetrons for SRF Sources

    SciTech Connect

    Neubauer, Michael; Johnson, Rolland

    2014-09-12

    There is great potential for a magnetron power source that can be controlled both in phase and frequency. Such a power source could revolutionize many particle accelerator systems that require lower capital cost and/or higher power efficiency. Beyond the accelerator community, phase and frequency locked magnetons could improve radar systems around the world and make affordable phased arrays for wireless power transmission for solar powered satellites. This joint project of Muons, Inc., Fermilab, and L-3 CTL was supported by an STTR grant monitored by the Nuclear Physics Office of the DOE Office of Science. The object of the program was to incorporate ferrite materials into the anode of a magnetron and, with appropriate biasing of the ferrites, to maintain frequency lock and to allow for frequency adjustment of the magnetron without mechanical tuners. If successful, this device would have a dual use both as a source for SRF linacs and for military applications where fast tuning of the frequency is a requirement. In order to place the materials in the proper location, several attributes needed to be modeled. First the impact of the magnetron’s magnetic field needed to be shielded from the ferrites so that they were not saturated. And second, the magnetic field required to change the frequency of the magnetron at the ferrites needed to be shielded from the region containing the circulating electrons. ANSYS calculations of the magnetic field were used to optimize both of these parameters. Once the design for these elements was concluded, parts were fabricated and a complete test assembly built to confirm the predictions of the computer models. The ferrite material was also tested to determine its compatibility with magnetron tube processing temperatures. This required a vacuum bake out of the chosen material to determine the cleanliness of the material in terms of outgassing characteristics, and a subsequent room temperature test to verify that the characteristics of

  8. Antibacterial PVD coatings doped with silver by ion implantation

    NASA Astrophysics Data System (ADS)

    Osés, J.; Palacio, J. F.; Kulkarni, S.; Medrano, A.; García, J. A.; Rodríguez, R.

    2014-08-01

    The antibacterial effect of certain metal ions, like silver, has been exploited since antiquity. Obviously, the ways to employ the biocide activity of this element have evolved throughout time and it is currently used in a wide range of clinical applications. The work presented here reports the results of an investigation focused on combining the protective properties of PVD coatings with the biocide property of silver, applied by ion implantation. For this purpose, chromium nitride layers were doped with silver implanted at two different doses (5 × 1016 and 1 × 1017 ion/cm2) at 100 keV of energy and perpendicular incidence. Full characterization of the coatings was performed to determine its topographical and mechanical properties. The concentration profile of Ag was analyzed by GD-OES. The thickness of the layers, nano-hardness, roughness, wear resistance and coefficient of friction were measured. Finally, the anti-bacterial efficacy of the coatings was determined following the JIS Z-2801:2010 Standard. The results provide clear insights into the efficacy of silver for antibacterial purposes, as well as on its influence in the mechanical and tribological behaviour of the coatings matrix.

  9. Characterization of tantalum nitride thin films synthesized by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Zaman, Anna

    Tantalum Nitride is chemically inert, oxidation resistant and hard. TaN finds its application as a protective coating on steel due to their excellent wear properties. It has become a very promising diffusion barrier material in Cu interconnect technology in microelectronics. TaN has not been analyzed as much as other transition metal nitrides like the TiN system because TaN exhibits various stable and metastable phases. The emergence of these phases and the different physical, chemical and mechanical properties depend on the growth technique and deposition conditions. TaN thin films were deposited using the magnetron PVD system in the SaNEL lab. The aim of this study was to identify the effect of processing parameters like N2/Ar ratio, substrate bias and temperature, on the emergence of the different phases present in TaN thin films and the effect of deposition conditions on the mechanical properties of these films. The phases present in the films, deposited at varying conditions were explored via low angle X-Ray Diffraction (XRD), hardness of the films was measured by Nanoindentation and tribological tests were carried out to measure the frictional and wear behavior. It was observed that at high percentage of Nitrogen (10%-25%) the main phase present was FCC TaN and as the nitrogen content was decreased a mixture of phases was present in these films. The hardness of the films increases as we decrease the Nitrogen content, yielding a film with a hardness of 37.1 GPa at 3% N2 with a substrate bias voltage of -100 V.

  10. Plasma Spray-PVD: A New Thermal Spray Process to Deposit Out of the Vapor Phase

    NASA Astrophysics Data System (ADS)

    von Niessen, Konstantin; Gindrat, Malko

    2011-06-01

    Plasma spray-physical vapor deposition (PS-PVD) is a low pressure plasma spray technology recently developed by Sulzer Metco AG (Switzerland). Even though it is a thermal spray process, it can deposit coatings out of the vapor phase. The basis of PS-PVD is the low pressure plasma spraying (LPPS) technology that has been well established in industry for several years. In comparison to conventional vacuum plasma spraying (VPS) or low pressure plasma spraying (LPPS), the new proposed process uses a high energy plasma gun operated at a reduced work pressure of 0.1 kPa (1 mbar). Owing to the high energy plasma and further reduced work pressure, PS-PVD is able to deposit a coating not only by melting the feed stock material which builds up a layer from liquid splats but also by vaporizing the injected material. Therefore, the PS-PVD process fills the gap between the conventional physical vapor deposition (PVD) technologies and standard thermal spray processes. The possibility to vaporize feedstock material and to produce layers out of the vapor phase results in new and unique coating microstructures. The properties of such coatings are superior to those of thermal spray and electron beam-physical vapor deposition (EB-PVD) coatings. In contrast to EB-PVD, PS-PVD incorporates the vaporized coating material into a supersonic plasma plume. Owing to the forced gas stream of the plasma jet, complex shaped parts such as multi-airfoil turbine vanes can be coated with columnar thermal barrier coatings using PS-PVD. Even shadowed areas and areas which are not in the line of sight of the coating source can be coated homogeneously. This article reports on the progress made by Sulzer Metco in developing a thermal spray process to produce coatings out of the vapor phase. Columnar thermal barrier coatings made of Yttria-stabilized Zircona (YSZ) are optimized to serve in a turbine engine. This process includes not only preferable coating properties such as strain tolerance and erosion

  11. A review-application of physical vapor deposition (PVD) and related methods in the textile industry

    NASA Astrophysics Data System (ADS)

    Shahidi, Sheila; Moazzenchi, Bahareh; Ghoranneviss, Mahmood

    2015-09-01

    Physical vapor deposition (PVD) is a coating process in which thin films are deposited by the condensation of a vaporized form of the desired film material onto the substrate. The PVD process is carried out in a vacuum. PVD processes include different types, such as: cathode arc deposition, electron beam physical vapor deposition, evaporative deposition, sputtering, ion plating and enhanced sputtering. In the PVD method, the solid coating material is evaporated by heat or by bombardment with ions (sputtering). At the same time, a reactive gas is also introduced; it forms a compound with the metal vapor and is deposited on the substrate as a thin film with highly adherent coating. Such coatings are used in a wide range of applications such as aerospace, automotive, surgical, medical, dyes and molds for all manner of material processing, cutting tools, firearms, optics, thin films and textiles. The objective of this work is to give a comprehensive description and review of the science and technology related to physical vapor deposition with particular emphasis on their potential use in the textile industry. Physical vapor deposition has opened up new possibilities in the modification of textile materials and is an exciting prospect for usage in textile design and technical textiles. The basic principle of PVD is explained and the major applications, particularly sputter coatings in the modification and functionalization of textiles, are introduced in this research.

  12. Characterization of hydrogenated and deuterated silicon carbide films codeposited by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Pantelica, D.; Ionescu, P.; Petrascu, H.; Dracea, M. D.; Statescu, M.; Matei, E.; Rasoga, O.; Stancu, C.; Marascu, V.; Ion, V.; Acsente, T.; Dinescu, G.

    2016-03-01

    In this work we present the deposition of amorphous SiC thin films by radiofrequency dual magnetron sputtering. The dependence of the deposited films properties over the discharges electrical power and the effect of hydrogenous species (H2 and/or D2) addition to main discharge gas (Ar) were investigated. Accurate elemental analysis of the samples, including detection of hydrogen and deuterium, was performed by ion beam analysis (IBA) techniques: RBS (Rutherford Backscattering Spectrometry) and ERDA (Elastic Recoil Detection Analysis). SiCx thin films with thicknesses between 1700 and 4500 Å and C/Si ratio between 0.2/1 and 1.25/1 were obtained in different deposition conditions. The results prove that thin films of amorphous SiC with well controlled properties can be produced using radiofrequency dual magnetron sputtering.

  13. PvdP is a tyrosinase that drives maturation of the pyoverdine chromophore in Pseudomonas aeruginosa.

    PubMed

    Nadal-Jimenez, Pol; Koch, Gudrun; Reis, Carlos R; Muntendam, Remco; Raj, Hans; Jeronimus-Stratingh, C Margot; Cool, Robbert H; Quax, Wim J

    2014-07-01

    The iron binding siderophore pyoverdine constitutes a major adaptive factor contributing to both virulence and survival in fluorescent pseudomonads. For decades, pyoverdine production has allowed the identification and classification of fluorescent and nonfluorescent pseudomonads. Here, we demonstrate that PvdP, a periplasmic enzyme of previously unknown function, is a tyrosinase required for the maturation of the pyoverdine chromophore in Pseudomonas aeruginosa. PvdP converts the nonfluorescent ferribactin, containing two iron binding groups, into a fluorescent pyoverdine, forming a strong hexadentate complex with ferrous iron, by three consecutive oxidation steps. PvdP represents the first characterized member of a small family of tyrosinases present in fluorescent pseudomonads that are required for siderophore maturation and are capable of acting on large peptidic substrates. PMID:24816606

  14. PvdP Is a Tyrosinase That Drives Maturation of the Pyoverdine Chromophore in Pseudomonas aeruginosa

    PubMed Central

    Nadal-Jimenez, Pol; Koch, Gudrun; Reis, Carlos R.; Muntendam, Remco; Raj, Hans; Jeronimus-Stratingh, C. Margot; Cool, Robbert H.

    2014-01-01

    The iron binding siderophore pyoverdine constitutes a major adaptive factor contributing to both virulence and survival in fluorescent pseudomonads. For decades, pyoverdine production has allowed the identification and classification of fluorescent and nonfluorescent pseudomonads. Here, we demonstrate that PvdP, a periplasmic enzyme of previously unknown function, is a tyrosinase required for the maturation of the pyoverdine chromophore in Pseudomonas aeruginosa. PvdP converts the nonfluorescent ferribactin, containing two iron binding groups, into a fluorescent pyoverdine, forming a strong hexadentate complex with ferrous iron, by three consecutive oxidation steps. PvdP represents the first characterized member of a small family of tyrosinases present in fluorescent pseudomonads that are required for siderophore maturation and are capable of acting on large peptidic substrates. PMID:24816606

  15. Structural characterization and high throughput screening of inhibitors of PvdQ, an NTN hydrolase involved in pyoverdine synthesis

    PubMed Central

    Drake, Eric J.; Gulick, Andrew M.

    2011-01-01

    The human pathogen Pseudomonas aeruginosa produces a variety of virulence factors including pyoverdine, a non-ribosomally produced peptide siderophore. The maturation pathway of the pyoverdine peptide is complex and provides a unique target for inhibition. Within the pyoverdine biosynthetic cluster is a periplasmic hydrolase, PvdQ, that is required for pyoverdine production. However, the precise role of PvdQ in the maturation pathway has not been biochemically characterized. We demonstrate herein that the initial module of the nonribosomal peptide synthetase PvdL adds a myristate moiety to the pyoverdine precursor. We extracted this acylated precursor, called PVDIq, from a pvdQ mutant strain and show that the PvdQ enzyme removes the fatty acid catalyzing one of the final steps in pyoverdine maturation. Incubation of PVDIq with crystals of PvdQ allowed us to capture the acylated enzyme and confirm through structural studies the chemical composition of the incorporated acyl chain. Finally, because inhibition of siderophore synthesis has been identified as a potential antibiotic strategy, we developed a high throughput screening assay and tested a small chemical library for compounds that inhibit PvdQ activity. Two compounds that block PvdQ have been identified and their binding within the fatty acid binding pocket structurally characterized. PMID:21892836

  16. Identification of inhibitors of PvdQ, an enzyme involved in the synthesis of the siderophore pyoverdine.

    PubMed

    Wurst, Jacqueline M; Drake, Eric J; Theriault, Jimmy R; Jewett, Ivan T; VerPlank, Lynn; Perez, Jose R; Dandapani, Sivaraman; Palmer, Michelle; Moskowitz, Samuel M; Schreiber, Stuart L; Munoz, Benito; Gulick, Andrew M

    2014-07-18

    Pseudomonas aeruginosa produces the peptide siderophore pyoverdine, which is used to acquire essential Fe(3+) ions from the environment. PvdQ, an Ntn hydrolase, is required for the biosynthesis of pyoverdine. PvdQ knockout strains are not infectious in model systems, suggesting that disruption of siderophore production via PvdQ inhibition could be exploited as a target for novel antibacterial agents, by preventing cells from acquiring iron in the low iron environments of most biological settings. We have previously described a high-throughput screen to identify inhibitors of PvdQ that identified inhibitors with IC50 values of ∼100 μM. Here, we describe the discovery of ML318, a biaryl nitrile inhibitor of PvdQ acylase. ML318 inhibits PvdQ in vitro (IC50 = 20 nM) by binding in the acyl-binding site, as confirmed by the X-ray crystal structure of PvdQ bound to ML318. Additionally, the PvdQ inhibitor is active in a whole cell assay, preventing pyoverdine production and limiting the growth of P. aeruginosa under iron-limiting conditions. PMID:24824984

  17. Plasma Spray-PVD: Plasma Characteristics and Impact on Coating Properties

    NASA Astrophysics Data System (ADS)

    Mauer, G.; Vaßen, R.

    2012-12-01

    Typical plasma characteristics of the plasma spray-physical vapour deposition (PS-PVD) process were investigated by optical emission spectroscopy. Electron temperatures were determined by Boltzmann plots while temperatures of the heavy species as well as electron densities were obtained by broadening analysis of spectral lines. The results show how the plasma properties and thermodynamic equilibrium conditions are affected by the admixture of hydrogen and the ambient chamber pressure. Some experimental examples of PS-PVD coatings demonstrate the impact on feedstock treatment and deposited microstructures.

  18. Experimental radiation cooled magnetrons for space

    NASA Technical Reports Server (NTRS)

    Brown, W. C.; Pollock, M.

    1991-01-01

    The heat disposal problem that occurs in the microwave generator of the Solar Power Satellite when it converts dc power from solar photovoltaic arrays into microwave power for transmission to earth is examined. A theoretical study is made of the radiation cooling of a magnetron directional amplifier, and some experimental data obtained from the QKH 2244 magnetron are presented. This instrument is an unpackaged microwave oven magnetron to which an anodized aluminum radiator has been attached and whose magnetic field is supplied by special samarium cobalt magnets.

  19. Experimental radiation cooled magnetrons for space

    NASA Astrophysics Data System (ADS)

    Brown, W. C.; Pollock, M.

    The heat disposal problem that occurs in the microwave generator of the Solar Power Satellite when it converts dc power from solar photovoltaic arrays into microwave power for transmission to earth is examined. A theoretical study is made of the radiation cooling of a magnetron directional amplifier, and some experimental data obtained from the QKH 2244 magnetron are presented. This instrument is an unpackaged microwave oven magnetron to which an anodized aluminum radiator has been attached and whose magnetic field is supplied by special samarium cobalt magnets.

  20. PvD1 defensin, a plant antimicrobial peptide with inhibitory activity against Leishmania amazonensis.

    PubMed

    do Nascimento, Viviane V; Mello, Érica de O; Carvalho, Laís P; de Melo, Edésio J T; Carvalho, André de O; Fernandes, Katia V S; Gomes, Valdirene M

    2015-01-01

    Plant defensins are small cysteine-rich peptides and exhibit antimicrobial activity against a variety of both plant and human pathogens. Despite the broad inhibitory activity that plant defensins exhibit against different micro-organisms, little is known about their activity against protozoa. In a previous study, we isolated a plant defensin named PvD1 from Phaseolus vulgaris (cv. Pérola) seeds, which was seen to be deleterious against different yeast cells and filamentous fungi. It exerted its effects by causing an increase in the endogenous production of ROS (reactive oxygen species) and NO (nitric oxide), plasma membrane permeabilization and the inhibition of medium acidification. In the present study, we investigated whether PvD1 could act against the protozoan Leishmania amazonensis. Our results show that, besides inhibiting the proliferation of L. amazonensis promastigotes, the PvD1 defensin was able to cause cytoplasmic fragmentation, formation of multiple cytoplasmic vacuoles and membrane permeabilization in the cells of this organism. Furthermore, we show, for the first time, that PvD1 defensin was located within the L. amazonensis cells, suggesting the existence of a possible intracellular target. PMID:26285803

  1. Pyoverdine and beyond: PvdS dependent gene regulation in Pseudomonas syringae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The extracytoplasmic function (ECF) sigma factor PvdS regulates the expression of genes in Pseudomonas aeruginosa encoding virulence factors and the biosynthesis and transport of pyoverdine, a siderophore involved in iron acquisition. The production of pyoverdine is a distinctive trait of the fluor...

  2. Electrical Properties of Gamma Irradiated PVdF Based Polymer Electrolytes

    SciTech Connect

    Ayoub, N.; Amin, Y. M.; Arof, A. K.

    2010-07-07

    The effect of different doses of {gamma}-irradiation on the conductivity of PVdF-LiPF{sub 6} solid polymer electrolyte (SPE) was investigated at room temperature. The dielectric constant and loss are seen to increase with increasing radiation doses.

  3. PvD1 defensin, a plant antimicrobial peptide with inhibitory activity against Leishmania amazonensis

    PubMed Central

    do Nascimento, Viviane V.; Mello, Érica de O.; Carvalho, Laís P.; de Melo, Edésio J.T.; Carvalho, André de O.; Fernandes, Katia V.S.; Gomes, Valdirene M.

    2015-01-01

    Plant defensins are small cysteine-rich peptides and exhibit antimicrobial activity against a variety of both plant and human pathogens. Despite the broad inhibitory activity that plant defensins exhibit against different micro-organisms, little is known about their activity against protozoa. In a previous study, we isolated a plant defensin named PvD1 from Phaseolus vulgaris (cv. Pérola) seeds, which was seen to be deleterious against different yeast cells and filamentous fungi. It exerted its effects by causing an increase in the endogenous production of ROS (reactive oxygen species) and NO (nitric oxide), plasma membrane permeabilization and the inhibition of medium acidification. In the present study, we investigated whether PvD1 could act against the protozoan Leishmania amazonensis. Our results show that, besides inhibiting the proliferation of L. amazonensis promastigotes, the PvD1 defensin was able to cause cytoplasmic fragmentation, formation of multiple cytoplasmic vacuoles and membrane permeabilization in the cells of this organism. Furthermore, we show, for the first time, that PvD1 defensin was located within the L. amazonensis cells, suggesting the existence of a possible intracellular target. PMID:26285803

  4. A Plasma Lens for Magnetron Sputtering

    SciTech Connect

    Anders, Andre; Brown, Jeff

    2010-11-30

    A plasma lens, consisting of a solenoid and potential-defining ring electrodes, has been placed between a magnetron and substrates to be coated. Photography reveals qualitative information on excitation, ionization, and the transport of plasma to the substrate.

  5. Peer-to-Peer Magnetron Locking

    NASA Astrophysics Data System (ADS)

    Cruz, Edward Jeffrey

    The viability of coherent power combination of multiple high-efficiency, moderate power magnetrons requires a thorough understanding of frequency and phase control. Injection locking of conventional magnetrons, and other types of oscillators, employing a master-to-slave configuration has been studied theoretically and experimentally. This dissertation focuses on the peer-to-peer locking, where each oscillator acts as a master of and slave to all others, between two conventional magnetrons, where the general condition for locking was recently derived. The experiments performed on peer-to-peer locking of two 1-kW magnetrons verify the recently developed theory on the condition under which the two nonlinear oscillators may be locked to a common frequency and relative phase. This condition reduces to Adler's classical locking condition (master-slave) if the coupling is one way. Dependent on the degree of coupling, the frequency of oscillation when locking occurs was found to not necessarily lie between the two magnetrons' free running frequencies. Likewise, when the locking condition was violated, the beat of the spectrum was not necessarily found to be equal to the difference between the free running frequencies. The frequency of oscillation and relative phase between the two magnetrons when locking did occur were found to correspond to one of two solution modes given by the recent theory. The accessibility of the two possible modes is yet to be determined. This work was supported by ONR, AFRL, AFOSR, L-3 Communications Electron Devices Division and Northrop-Grumman Corporation.

  6. Thermal Conductivity of EB-PVD Thermal Barrier Coatings Evaluated by a Steady-State Laser Heat Flux Technique

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.; Nagaraj, Ben A.; Bruce, Robert W.

    2000-01-01

    The thermal conductivity of electron beam-physical vapor deposited (EB-PVD) Zr02-8wt%Y2O3 thermal barrier coatings was determined by a steady-state heat flux laser technique. Thermal conductivity change kinetics of the EB-PVD ceramic coatings were also obtained in real time, at high temperatures, under the laser high heat flux, long term test conditions. The thermal conductivity increase due to micro-pore sintering and the decrease due to coating micro-delaminations in the EB-PVD coatings were evaluated for grooved and non-grooved EB-PVD coating systems under isothermal and thermal cycling conditions. The coating failure modes under the high heat flux test conditions were also investigated. The test technique provides a viable means for obtaining coating thermal conductivity data for use in design, development, and life prediction for engine applications.

  7. The Photovoltaic Performances of PVdF-HFP Electrospun Membranes Employed Quasi-Solid-State Dye Sensitized Solar Cells.

    PubMed

    Gnana kumar, G; Balanay, Mannix P; Nirmala, R; Kim, Dong Hee; Raj kumar, T; Senthilkumar, N; Kim, Ae Rhan; Yoo, Dong Jin

    2016-01-01

    The PVdF-HFP nanofiber membranes with different molecular weight were prepared by electrospinning technique and were investigated as solid state electrolyte membranes in quasi solid state dye sensitized solar cells (QS-DSSC). The homogeneously distributed and fully interconnected nanofibers were obtained for all of the prepared PVdF-HFP electrospun membranes and the average fiber diameters of fabricated membranes were dependent upon the molecular weight of polymer. The thermal stability of electrospun PVdF-HFP membrane was decreased with a decrement of molecular weight, specifying the high heat transfer area of small diameter nanofibers. The QS-DSSC fabricated with the lower molecular weight PVdF-HFP electrospun nanofiber membrane exhibited the power conversion efficiency of 1 = 5.38%, which is superior over the high molecular weight membranes and is comparable with the liquid electrolyte. Furthermore, the electrospun PVdF-HFP membrane exhibited long-term durability over the liquid electrolyte, owing to the higher adsorption and retention efficiencies of liquid electrolyte in its highly porous and interconnected nanofibers. Thus the proposed electrospun PVdF-HFP membrane effectively tackled the volatilization and leakage of liquid electrolyte and provided good photoconversion efficiency associated with an excellent stability, which constructs the prepared electrospun membranes as credible solid state candidates for the application of QS-DSSCs. PMID:27398491

  8. Stability of Brillouin flow in planar, conventional, and inverted magnetrons

    NASA Astrophysics Data System (ADS)

    Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Hoff, B. W.; Gilgenbach, R. M.

    2015-08-01

    The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions.

  9. Stability of Brillouin flow in planar, conventional, and inverted magnetrons

    SciTech Connect

    Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Gilgenbach, R. M.; Hoff, B. W.

    2015-08-15

    The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions.

  10. Low target power wafer sputtering regime identified during magnetron tantalum barrier physical vapor deposition

    SciTech Connect

    Stout, Phillip J.; Denning, Dean J.; Michaelson, Lynne M.; Bagchi, Sandeep; Zhang Da; Ventzek, Peter L. G.

    2005-07-15

    A wafer sputtering regime has been identified during tantalum barrier deposition using a magnetron physical vapor deposition (MPVD) tool. The MPVD tools are designed to operate at high target powers (tens of kW) where the highly directed energetic metal (athermal metal) is the dominant metal species incident on the wafer. Although athermal metal gives better coverage than neutral metal (thermal) due to the narrower range of incident strike angles to the wafer, shadowing by the feature geometries is still a concern. Having available a wafer sputter regime or 'resputter' regime in a PVD tool allows for redistribution of metal from horizontal surfaces in the feature exposed to the plasma to vertical surfaces in the feature. The key in obtaining a wafer sputter regime is the operation of the plasma source in a range that the wafer bias power is effective at generating a sufficient self-bias for sputtering to occur. Discussed are modeling results which predict the wafer sputtering regime and the experimental confirmation that the low target power wafer sputter regime exists. The identified sputter regime in MPVD is such that there is a net deposition of metal at the field. Metal thickness reduction does occur at the trench and via bottoms where much of the unionized metal is being shadowed yielding a lower deposition to sputtering ratio compared to the field.

  11. Functional expression and activity of the recombinant antifungal defensin PvD1r from Phaseolus vulgaris L. (common bean) seeds

    PubMed Central

    2014-01-01

    Background Defensins are basic, cysteine-rich antimicrobial peptides that are important components of plant defense against pathogens. Previously, we isolated a defensin, PvD1, from Phaseolus vulgaris L. (common bean) seeds. Results The aim of this study was to overexpress PvD1 in a prokaryotic system, verify the biologic function of recombinant PvD1 (PvD1r) by comparing the antimicrobial activity of PvD1r to that of the natural defensin, PvD1, and use a mutant Candida albicans strain that lacks the gene for sphingolipid biosynthesis to unravel the target site of the PvD1r in C. albicans cells. The cDNA encoding PvD1, which was previously obtained, was cloned into the pET-32 EK/LIC vector, and the resulting construct was used to transform bacterial cells (Rosetta Gami 2 (DE3) pLysS) leading to recombinant protein expression. After expression had been induced, PvD1r was purified, cleaved with enterokinase and repurified by chromatographic steps. N-terminal amino acid sequencing showed that the overall process of the recombinant production of PvD1r, including cleavage with the enterokinase, was successful. Additionally, modeling revealed that PvD1r had a structure that was similar to the defensin isolated from plants. Purified PvD1 and PvD1r possessed inhibitory activity against the growth of the wild-type pathogenic yeast strain C. albicans. Both defensins, however, did not present inhibitory activity against the mutant strain of C. albicans. Antifungal assays with the wild-type C. albicans strains showed morphological changes upon observation by light microscopy following growth assays. PvD1r was coupled to FITC, and the subsequent treatment of wild type C. albicans with DAPI revealed that the labeled peptide was intracellularly localized. In the mutant strain, no intracellular labeling was detected. Conclusion Our results indicate that PvD1r retains full biological activity after recombinant production, enterokinase cleavage and purification. Additionally, our

  12. Analysis of peer-to-peer locking of magnetrons

    SciTech Connect

    Pengvanich, P.; Lau, Y. Y.; Cruz, E.; Gilgenbach, R. M.; Hoff, B.; Luginsland, J. W.

    2008-10-15

    The condition for mutual, or peer-to-peer, locking of two magnetrons is derived. This condition reduces to Adler's classical phase-locking condition in the limit where one magnetron becomes the 'master' and the other becomes the 'slave.' The formulation is extended to the peer-to-peer locking of N magnetrons, under the assumption that the electromagnetic coupling among the N magnetrons is modeled by an N-port network.

  13. Tribological and structural properties of titanium nitride and titanium aluminum nitride coatings deposited with modulated pulsed power magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Ward, Logan

    The demand for economical high-performance materials has brought attention to the development of advanced coatings. Recent advances in high power magnetron sputtering (HPPMS) have shown to improve tribological properties of coatings. These coatings offer increased wear and oxidation resistance, which may facilitate the use of more economical materials in harsh applications. This study demonstrates the use of novel forms of HPPMS, namely modulated pulsed-power magnetron sputtering (MPPMS) and deep oscillation magnetron sputtering (DOMS), for depositing TiN and Ti1-xAlxN tribological coatings on commonly used alloys, such as Ti-6Al-4V and Inconel 718. Both technologies have been shown to offer unique plasma characteristics in the physical vapor deposition (PVD) process. High power pulses lead to a high degree of ionization compared to traditional direct-current magnetron sputtering (DCMS) and pulsed magnetron sputtering (PMS). Such a high degree of ionization was previously only achievable by cathodic arc deposition (CAD); however, CAD can lead to increased macroparticles that are unfavorable in high friction and corrosive environments. MPPMS, DOMS, and other HPPMS techniques offer unique plasma characteristics and have been shown to produce coatings with refined grain structure, improved density, hardness, adhesion, and wear resistance. Using DOMS and MPPMS, TiN and Ti1-xAlxN coatings were deposited using PMS to compare microstructures and tribological performance. For Ti1-xAlxN, two sputtering target compositions, Ti 0.5Al0.5 and Ti0.3Al0.7, were used to evaluate the effects of MPPMS on the coating's composition and tribological properties. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to characterize microstructure and crystallographic texture. Several tribological properties were evaluated including: wear rate, coefficient of friction, adhesion, and nanohardness. Results show that substrate

  14. Plasma Spray-Physical Vapor Deposition (PS-PVD) of Ceramics for Protective Coatings

    NASA Technical Reports Server (NTRS)

    Harder, Bryan J.; Zhu, Dongming

    2011-01-01

    In order to generate advanced multilayer thermal and environmental protection systems, a new deposition process is needed to bridge the gap between conventional plasma spray, which produces relatively thick coatings on the order of 125-250 microns, and conventional vapor phase processes such as electron beam physical vapor deposition (EB-PVD) which are limited by relatively slow deposition rates, high investment costs, and coating material vapor pressure requirements. The use of Plasma Spray - Physical Vapor Deposition (PS-PVD) processing fills this gap and allows thin (< 10 microns) single layers to be deposited and multilayer coatings of less than 100 microns to be generated with the flexibility to tailor microstructures by changing processing conditions. Coatings of yttria-stabilized zirconia (YSZ) were applied to NiCrAlY bond coated superalloy substrates using the PS-PVD coater at NASA Glenn Research Center. A design-of-experiments was used to examine the effects of process variables (Ar/He plasma gas ratio, the total plasma gas flow, and the torch current) on chamber pressure and torch power. Coating thickness, phase and microstructure were evaluated for each set of deposition conditions. Low chamber pressures and high power were shown to increase coating thickness and create columnar-like structures. Likewise, high chamber pressures and low power had lower growth rates, but resulted in flatter, more homogeneous layers

  15. Nanomechanical study of thin film nanocomposite and PVD thin films on polymer substrates for optical applications

    NASA Astrophysics Data System (ADS)

    Moghal, Jonathan; Bird, Andrew; Harris, Adrian H.; Beake, Ben D.; Gardener, Martin; Wakefield, Gareth

    2013-12-01

    The mechanical properties of ultrathin (<120 nm) films differ substantially from the bulk properties of the material and are also strongly substrate dependent. We compare the properties of two differing film systems; a high particle loading nanocomposite of silica and a multiple layer physical vapour deposition (PVD) coating by nanoindentation, nano-scratch and nano-impact followed by structural analysis. The work is undertaken on hardcoated polymer substrates and uses two types of anti-reflection coatings as test systems. The nanocomposite film comprises of a high (>50%) loading of silica nanoparticles in an inorganic binder, which demonstrates significant flex and elastic recovery whereas PVD films are subject to brittle failure even at low applied loads. Failure of the nanocomposite film, with the exception of minor plastic deformation, does not occur until the underlying substrate fails. Although the PVD film has a greater hardness than the nanocomposite, failure occurs at lower loads due to a number of toughness reducing factors including reduced modulus, modulus mismatch with the substrate and film thickness. The resistance of ultrathin films to external mechanical stresses is therefore related to a number of factors and not simply to film hardness, the most important of which are film structure and film mechanical matching to the substrate.

  16. Non-Neutral Drift Resonance in Magnetrons

    NASA Astrophysics Data System (ADS)

    Kaup, D. J.

    2005-04-01

    We study the features of the RF fields in a magnetron, when the RF amplitude has saturated, in the nonrelativistic, electrostatic limit. In this saturated stage, the linear RF equations can be reduced to a fifth-order set of ordinary differential equations. Two modes of which are fast cyclotron modes, one mode is a fast drift wave, and the other two modes are the usual, well-known, slow magnetron modes. Here, we will study the interaction between the fast drift mode (diocotron mode) and the slow magnetron modes, at the diocotron resonance. We will also show that the fast cyclotron modes can be ignored at this resonance, and thereby can reduce the system to a third- order set of ordinary differential equations. Using multiscale techniques, we will then obtain solutions for the inner and the outer regions at the diocotron resonance, and thereby obtain the conversion and transmission rates between these three modes at the diocotron resonance.

  17. Hybrid diffusive/PVD treatments to improve the tribological resistance of Ti-6Al-4V.

    PubMed

    Marin, E; Offoiach, R; Lanzutti, A; Regis, M; Fusi, S; Fedrizzi, L

    2014-01-01

    Titanium alloys are nowadays used for a wide range of biomedical applications thanks to their combination of high mechanical resistance, high corrosion resistance and biocompatibility. Nevertheless, the applicability of titanium alloys is sometimes limited due to their low microhardness and tribological resistance. Thus the titanium alloys cannot be successfully applied to prosthetic joint couplings. A wide range of surface treatments, in particular PVD coatings such as CrN and TiN, have been used in order to improve the tribological behaviour of titanium alloys. However, the low microhardness of the titanium substrate often results in coating failure due to cracks and delamination. For this reason, hybrid technologies based on diffusive treatments and subsequent PVD coatings may improve the overall coating resistance. In this work, conventional PVD coatings of CrN or TiCN, deposited on Titanium Grade 5, were characterized and then combined with a standard thermal diffusive nitriding treatment in order to improve the tribological resistance of the titanium alloys and avoid coating delamination. The different treatments were studied by means of scanning electron microscopy both on the sample surface and in cross-section. In-depth composition profiles were obtained using glow discharge optical emission spectrometry (GDOES) and localized energy dispersive X-ray diffraction on linear scan-lines. The microhardness and adhesion properties of the different treatments were evaluated using Vickers microhardness tests at different load conditions. The indentations were observed by means of SEM in order to evaluate delaminated areas and the crack's shape and density. The tribological behaviour of the different treatments was tested in dry conditions and in solution, in alternate pin-on-flat configuration, with a frequency of 0.5 Hz. After testing, the surface was investigated by means of stylus profilometry and SEM both on the surface and in cross-section. The standalone PVD

  18. Effect of substrate temperature on the structural properties of magnetron sputtered titanium nitride thin films with brush plated nickel interlayer on mild steel

    NASA Astrophysics Data System (ADS)

    Subramanian, B.; Ashok, K.; Jayachandran, M.

    2008-12-01

    Thin films of titanium nitride (TiN) were prepared on mild steel (MS) by a physical vapor deposition (PVD) method namely direct current reactive magnetron sputtering. With the aim of improving the adhesion of TiN layer an additional Nickel interlayer was brush plated on the steel substrates prior to TiN film formation. The phase has been identified with X-ray diffraction (XRD) analysis, and the results show that the prominent peaks observed in the diffraction patterns correspond to the (1 1 1), (2 0 0) and (2 2 2) planes of TiN. Cross-sectional SEM indicated the presence of dense columnar structure. The mechanical properties (modulus and hardness) of these films were characterized by nanoindentation.

  19. IBA analysis and corrosion resistance of TiAlPtN/TiAlN/TiAl multilayer films deposited over a CoCrMo using magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Canto, C. E.; Andrade, E.; de Lucio, O.; Cruz, J.; Solís, C.; Rocha, M. F.; Alemón, B.; Flores, M.; Huegel, J. C.

    2016-03-01

    The corrosion resistance and the elemental profile of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by Physical Vapor Deposition (PVD) reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt to enhance the corrosion resistance of a biomedical alloy of CoCrMo. Corrosion tests were performed using Simulated Body Fluid (SBF) using potentiodynamic polarization tests at typical body temperature. The elemental composition and thickness of the coatings were evaluated with the combination of two ion beam analysis (IBA) techniques: a Rutherford Backscattering Spectroscopy (RBS) with alpha beam and a Nuclear Reaction Analysis with a deuteron beam.

  20. High power impulse magnetron sputtering discharge

    SciTech Connect

    Gudmundsson, J. T.; Brenning, N.; Lundin, D.; Helmersson, U.

    2012-05-15

    The high power impulse magnetron sputtering (HiPIMS) discharge is a recent addition to plasma based sputtering technology. In HiPIMS, high power is applied to the magnetron target in unipolar pulses at low duty cycle and low repetition frequency while keeping the average power about 2 orders of magnitude lower than the peak power. This results in a high plasma density, and high ionization fraction of the sputtered vapor, which allows better control of the film growth by controlling the energy and direction of the deposition species. This is a significant advantage over conventional dc magnetron sputtering where the sputtered vapor consists mainly of neutral species. The HiPIMS discharge is now an established ionized physical vapor deposition technique, which is easily scalable and has been successfully introduced into various industrial applications. The authors give an overview of the development of the HiPIMS discharge, and the underlying mechanisms that dictate the discharge properties. First, an introduction to the magnetron sputtering discharge and its various configurations and modifications is given. Then the development and properties of the high power pulsed power supply are discussed, followed by an overview of the measured plasma parameters in the HiPIMS discharge, the electron energy and density, the ion energy, ion flux and plasma composition, and a discussion on the deposition rate. Finally, some of the models that have been developed to gain understanding of the discharge processes are reviewed, including the phenomenological material pathway model, and the ionization region model.

  1. 1.2 Å resolution crystal structure of the periplasmic aminotransferase PvdN from Pseudomonas aeruginosa.

    PubMed

    Drake, Eric J; Gulick, Andrew M

    2016-05-01

    The Gram-negative pathogen Pseudomonas aeruginosa uses a nonribosomal peptide synthetase (NRPS) biosynthetic cluster for the production of a peptide siderophore. In addition to four multimodular NRPS proteins, the biosynthetic pathway also requires several additional enzymes involved in the production of nonproteinogenic amino acids and maturation of the peptide product. Among the proteins that are required for the final steps in pyoverdine synthesis is PvdN, a pyridoxal phosphate-dependent enzyme that catalyzes an uncharacterized step in pyoverdine production. This study reports the high-resolution structure of PvdN bound to a PLP cofactor solved by multi-wavelength anomalous dispersion (MAD). The PvdN model shows high structural homology to type I aspartate aminotransferases and also contains positive density that suggests an uncharacterized external aldimine. PMID:27139833

  2. Rational design of a transition state analogue with picomolar affinity for Pseudomonas aeruginosa PvdQ, a siderophore biosynthetic enzyme.

    PubMed

    Clevenger, Kenneth D; Wu, Rui; Er, Joyce A V; Liu, Dali; Fast, Walter

    2013-10-18

    The Pseudomonas aeruginosa enzyme PvdQ can process different substrates involved in quorum-sensing or in siderophore biosynthesis. Substrate selectivity was evaluated using steady-state kinetic constants for hydrolysis of N-acyl-homoserine lactones (HSLs) and p-nitrophenyl fatty acid esters. PvdQ prefers substrates with alkyl chains between 12 and 14 carbons long that do not bear a 3-oxo substitution and is revealed here to have a relatively high specificity constant for selected N-acyl-HSLs (kcat/KM = 10(5) to 10(6) M(-1) s(-1)). However, endogenous P. aeruginosa N-acyl-HSLs are ≥100-fold disfavored, supporting the conclusion that PvdQ was not primarily evolved to regulate endogenous quorum-sensing. PvdQ plays an essential biosynthetic role for the siderophore pyoverdine, on which P. aeruginosa depends for growth in iron-limited environments. A series of alkylboronate inhibitors was found to be reversible, competitive, and extremely potent (Ki ≥ 190 pM). A 1.8 Å X-ray structure shows that 1-tridecylboronic acid forms a monocovalent bond with the N-terminal β-chain Ser residue in the PvdQ heterodimer, mimicking a reaction transition state. This boronic acid inhibits growth of P. aeruginosa in iron-limited media, reproducing the phenotype of a genetic pvdQ disruption, although co-administration of an efflux pump inhibitor is required to maintain growth inhibition. These findings support the strategy of designing boron-based inhibitors of siderophore biosynthetic enzymes to control P. aeruginosa infections. PMID:23883096

  3. Magnetron cathodes in plasma electrode pockels cells

    DOEpatents

    Rhodes, Mark A.

    1995-01-01

    Magnetron cathodes, which produce high current discharges, form greatly improved plasma electrodes on each side of an electro-optic crystal. The plasma electrode has a low pressure gas region on both sides of the crystal. When the gas is ionized, e.g., by a glow discharge in the low pressure gas, the plasma formed is a good conductor. The gas electrode acts as a highly uniform conducting electrode. Since the plasma is transparent to a high energy laser beam passing through the crystal, the plasma is transparent. A crystal exposed from two sides to such a plasma can be charged up uniformly to any desired voltage. A typical configuration utilizes helium at 50 millitorr operating. pressure and 2 kA discharge current. The magnetron cathode produces a more uniform plasma and allows a reduced operating pressure which leads to lower plasma resistivity and a more uniform charge on the crystal.

  4. Magnetron cathodes in plasma electrode Pockels cells

    DOEpatents

    Rhodes, M.A.

    1995-04-25

    Magnetron cathodes, which produce high current discharges, form greatly improved plasma electrodes on each side of an electro-optic crystal. The plasma electrode has a low pressure gas region on both sides of the crystal. When the gas is ionized, e.g., by a glow discharge in the low pressure gas, the plasma formed is a good conductor. The gas electrode acts as a highly uniform conducting electrode. Since the plasma is transparent to a high energy laser beam passing through the crystal, the plasma is transparent. A crystal exposed from two sides to such a plasma can be charged up uniformly to any desired voltage. A typical configuration utilizes helium at 50 millitorr operating pressure and 2 kA discharge current. The magnetron cathode produces a more uniform plasma and allows a reduced operating pressure which leads to lower plasma resistivity and a more uniform charge on the crystal. 5 figs.

  5. Recirculating planar magnetrons: simulations and experiment

    SciTech Connect

    Franzi, Matthew; Gilgenbach, Ronald; French, David; Lau, Y.Y.; Simon, David; Hoff, Brad; Luginsland, John W.

    2011-07-01

    The Recirculating Planar Magnetron (RPM) is a novel crossed-field device whose geometry is expected to reduce thermal load, enhance current yield as well as ease the geometric limitations in scaling to high RF frequencies as compared to the conventional cylindrical magnetrons. The RPM has two different adaptations: A. Axial B field and radial E field; B. Radial B field and axial E field. The preliminary configuration (A) to be used in experiments at the University of Michigan consists of two parallel planar sections which join on either end by cylindrical regions to form a concentric extruded ellipse. Similar to conventional magnetrons, a voltage across the AK gap in conjunction with an axial magnetic field provides the electrons with an ExB drift. The device is named RPM because the drifting electrons recirculate from one planar region to the other. The drifting electrons interact with the resonantly tuned slow wave structure on the anode causing spoke formation. These electron spokes drive a RF electric field in the cavities from which RF power may be extracted to Waveguides. The RPM may be designed in either a conventional configuration with the anode on the outside, for simplified extraction, or as an inverted magnetron with the anode at the inner conductor, for fast start-up. Currently, experiments at the Pulsed Power and Microwave Laboratory at the University of Michigan are in the setup and design phase. A conventional RPM with planar cavities is to be installed on the Michigan Electron Long Beam Accelerator (MELBA) and is anticipated to operate at -200kV, 0.2T with a beam current of 1-10 kA at 1GHz. The conventional RPM consists of 12 identical planar cavities, 6 on each planar side, with simulated quality factor of 20.

  6. Particle contamination formation in magnetron sputtering processes

    SciTech Connect

    Selwyn, G.S.; Sequeda, F.; Huang, C.

    1997-07-01

    Defects caused by particulate contamination are an important concern in the fabrication of thin film products. Often, magnetron sputtering processes are used for this purpose. Particle contamination generated during thin film processing can be detected using laser light scattering, a powerful diagnostic technique which provides real-time, {ital in situ} imaging of particles {gt}0.3 {mu}m on the target, substrate, or in the plasma. Using this technique, we demonstrate that the mechanisms for particle generation, transport, and trapping during magnetron sputter deposition are different from the mechanisms reported in previously studied plasma etch processes, due to the inherent spatial nonuniformity of magnetically enhanced plasmas. During magnetron sputter deposition, one source of particle contamination is linked to portions of the sputtering target surface exposed to weaker plasma density. There, film redeposition induces filament or nodule growth. Sputter removal of these features is inhibited by the dependence of sputter yield on angle of incidence. These features enhance trapping of plasma particles, which then increases filament growth. Eventually the growths effectively {open_quotes}short-circuit{close_quotes} the sheath, causing high currents to flow through these features. This, in turn, causes mechanical failure of the growth resulting in fracture and ejection of the target contaminants into the plasma and onto the substrate. Evidence of this effect has been observed in semiconductor fabrication and storage disk manufacturing. Discovery of this mechanism in both technologies suggests it may be universal to many sputter processes. {copyright} {ital 1997 American Vacuum Society.}

  7. Failure of PVD/plasma sprayed thermal barrier coatings during thermal cycling

    SciTech Connect

    Teixeria, V.; Andritschky, M.; Gruhn, H.; Mallener, W.; Buchkremer, H.; Stoever, D.

    1995-12-31

    ZrO{sub 2}7Y{sub 2}O{sub 3} plasma sprayed coatings (PS top coating) were applied on high temperature Ni-based alloys precoated by Physical Vapor Deposition with a thin, dense, stabilized zirconia coating (PVD bond coat). The PS coatings were applied by Atmospheric Plasma Spraying (APS) and Inert gas Plasma Spraying (IPS at 2 bar) for different substrate temperatures. The thermal barrier coatings (TBCs) were tested by furnace isothermal cycling and flame thermal cycling at maximum temperatures between 1,000 C and 1,150 C. The temperature gradients within the duplex PVD/PS thermal barrier coatings during the thermal cycling process were modeled using an unsteady heat transfer program. This modeling enables the authors to calculate the transient thermal strains and stresses which contribute to a better understanding of the failure mechanisms of the TBC during thermal cycling. They have also studied experimentally the adherence and failure modes of these coating systems during this high temperature testing. The TBC failure mechanism during thermal cycling is discussed in the light of coating transient stresses and substrate oxidation.

  8. Method and apparatus for improved high power impulse magnetron sputtering

    DOEpatents

    Anders, Andre

    2013-11-05

    A high power impulse magnetron sputtering apparatus and method using a vacuum chamber with a magnetron target and a substrate positioned in the vacuum chamber. A field coil being positioned between the magnetron target and substrate, and a pulsed power supply and/or a coil bias power supply connected to the field coil. The pulsed power supply connected to the field coil, and the pulsed power supply outputting power pulse widths of greater that 100 .mu.s.

  9. Drastic improvement in the S-band relativistic magnetron operation

    SciTech Connect

    Sayapin, A.; Hadas, Y.; Krasik, Ya. E.

    2009-08-17

    The superior operation of a S-band relativistic magnetron powered by a Linear Induction Accelerator with {<=}400 kV, {<=}4 kA, and {approx}150 ns output pulses was revealed when the magnetron was coupled with a resonance load and a part of the generated microwave power stored in the resonator was reflected back to the magnetron. It is shown that, under optimal conditions, the efficiency of the magnetron operation increases by {approx}40% and the generated microwave power reaches the power of the electron beam.

  10. Drastic improvement in the S-band relativistic magnetron operation

    NASA Astrophysics Data System (ADS)

    Sayapin, A.; Hadas, Y.; Krasik, Ya. E.

    2009-08-01

    The superior operation of a S-band relativistic magnetron powered by a Linear Induction Accelerator with ≤400 kV, ≤4 kA, and ˜150 ns output pulses was revealed when the magnetron was coupled with a resonance load and a part of the generated microwave power stored in the resonator was reflected back to the magnetron. It is shown that, under optimal conditions, the efficiency of the magnetron operation increases by ˜40% and the generated microwave power reaches the power of the electron beam.

  11. Secondary-electrons-induced cathode plasma in a relativistic magnetron

    SciTech Connect

    Queller, T.; Gleizer, J. Z.; Krasik, Ya. E.

    2012-11-19

    Results of time- and space-resolved spectroscopic studies of cathode plasma during a S-band relativistic magnetron operation and a magnetically insulated diode having an identical interelectrode gap are presented. It was shown that in the case of the magnetron operation, one obtains an earlier, more uniform plasma formation due to energetic electrons' interaction with the cathode surface and ionization of desorbed surface monolayers. No differences were detected in the cathode's plasma temperature between the magnetron and the magnetically insulated diode operation, and no anomalous fast cathode plasma expansion was observed in the magnetron at rf power up to 350 MW.

  12. Satellite Power System (SPS) magnetron tube assessment study

    NASA Astrophysics Data System (ADS)

    Brown, W. C.

    1981-02-01

    The data base was extended with respect to the magnetron directional amplifier and its operating parameters that are pertinent to its application in the solar power satellite. On the basis of the resulting extended data base the design of a magnetron was outlined that would meet the requirements of the SPS application and a technology program was designed that would result in its development. The proposed magnetron design for the SPS is a close scale of the microwave oven magnetron, and resembles it closely physically and electrically.

  13. Satellite Power System (SPS) magnetron tube assessment study

    NASA Technical Reports Server (NTRS)

    Brown, W. C.

    1981-01-01

    The data base was extended with respect to the magnetron directional amplifier and its operating parameters that are pertinent to its application in the solar power satellite. On the basis of the resulting extended data base the design of a magnetron was outlined that would meet the requirements of the SPS application and a technology program was designed that would result in its development. The proposed magnetron design for the SPS is a close scale of the microwave oven magnetron, and resembles it closely physically and electrically.

  14. Turbulent electron beams generated by magnetron injection guns

    NASA Astrophysics Data System (ADS)

    Kalinin, Yu. A.; Starodubov, A. V.; Mushtakov, A. V.

    2011-06-01

    A detailed experimental investigation of oscillators based on a magnetron injection gun is carried out. Experimental data show that such oscillators offer a considerable advantage over other similar devices; namely, they are capable of generating powerful wideband noiselike microwave oscillations. This is because magnetron injection guns generate turbulent electron beams at their exit.

  15. Magnetron-Sputtered Amorphous Metallic Coatings

    NASA Technical Reports Server (NTRS)

    Thakoor, A. P.; Mehra, M.; Khanna, S. K.

    1985-01-01

    Amorphous coatings of refractory metal/metalloid-based alloys deposited by magnetron sputtering provide extraordinary hardness and wear resistance. Sputtering target fabricated by thoroughly mixing powders of tungsten, rhenium, and boron in stated proportions and pressing at 1,200 degrees C and 3,000 lb/in. to second power (21 MPa). Substrate lightly etched by sputtering before deposition, then maintained at bias of - 500 V during initial stages of film growth while target material sputtered onto it. Argon gas at pressure used as carrier gas for sputter deposition. Coatings dense, pinhole-free, extremely smooth, and significantly resistant to chemical corrosion in acidic and neutral aqueous environments.

  16. Influence of EB-PVD TBC Microstructure on Thermal Barrier Coating System Performance Under Cyclic Conditions

    SciTech Connect

    Leyens, C; Pint, B A; Schulz, U; Wright, I G

    1999-04-12

    The lifetimes of electron beam physical vapor deposited (EB-PVD) thermal barrier coating systems (TBCs) with three different microstructures of the Y2O3-stabilized ZrO, YSZ) ceramic top layer were investigated in lh thermal cycles at 1100 and 1150°C in flowing oxygen. Single crystal alloys CMSX-4 and Rene N5 that had been coated with an EB-PVD NiCoCrAlY bond coat were chosen as substrate materials. At 1150°C all samples failed after 80-100, lh cycles, predominantly at the bond coat/alumina interface after cooling down from test temperature. The alumina scale remained adherent to the YSZ after spallation. Despite the different YSZ microstructures no clear tendency regarding differences in spallation behavior were observed at 1150°C. At 1100°C the minimum lifetime was 750 , lh cycles for CMSX-4, whereas the first Rene N5 specimen failed after 1750, lh cycles. The longest TBC lifetime on CMSX-4 substrates was 1250, lh cycles, whereas the respective Rene N5 specimens have not yet failed after 2300, lh cycles. The failure mode at 1100°C was identical to that at 1150°C, i.e. the TBC spalled off the surface exposing bare metal after cooling. Even though not all specimens have failed to date, the available results at 1100°C suggested that both, the substrate alloy chemistry and the YSZ microstructure significantly affect the spallation resistance of the TBC.

  17. Injection moulding of optical functional micro structures using laser structured, PVD-coated mould inserts

    SciTech Connect

    Hopmann, Ch.; Weber, M.; Schöngart, M.; Schäfer, C.; Bobzin, K.; Bagcivan, N.; Brögelmann, T.; Theiß, S.; Münstermann, T.; Steger, M.

    2015-05-22

    Micro structured optical plastics components are intensively used i. e. in consumer electronics, for optical sensors in metrology, innovative LED-lighting or laser technology. Injection moulding has proven to be successful for the large-scale production of those parts. However, the production of those parts still causes difficulties due to challenges in the moulding and demoulding of plastics parts created with laser structured mould inserts. A complete moulding of the structures often leads to increased demoulding forces, which then cause a breaking of the structures and a clogging of the mould. An innovative approach is to combine PVD-coated (physical vapour deposition), laser structured inserts and a variothermal moulding process to create functional mic8iüro structures in a one-step process. Therefore, a PVD-coating is applied after the laser structuring process in order to improve the wear resistance and the anti-adhesive properties against the plastics melt. In a series of moulding trials with polycarbonate (PC) and polymethylmethacrylate (PMMA) using different coated moulds, the mould temperature during injection was varied in the range of the glass transition and the melt temperature of the polymers. Subsequently, the surface topography of the moulded parts is evaluated by digital 3D laser-scanning microscopy. The influence of the moulding parameters and the coating of the mould insert on the moulding accuracy and the demoulding behaviour are being analysed. It is shown that micro structures created by ultra-short pulse laser ablation can be successfully replicated in a variothermal moulding process. Due to the mould coating, significant improvements could be achieved in producing micro structured optical plastics components.

  18. Injection moulding of optical functional micro structures using laser structured, PVD-coated mould inserts

    NASA Astrophysics Data System (ADS)

    Hopmann, Ch.; Weber, M.; Schöngart, M.; Schäfer, C.; Bobzin, K.; Bagcivan, N.; Brögelmann, T.; Theiß, S.; Münstermann, T.; Steger, M.

    2015-05-01

    Micro structured optical plastics components are intensively used i. e. in consumer electronics, for optical sensors in metrology, innovative LED-lighting or laser technology. Injection moulding has proven to be successful for the large-scale production of those parts. However, the production of those parts still causes difficulties due to challenges in the moulding and demoulding of plastics parts created with laser structured mould inserts. A complete moulding of the structures often leads to increased demoulding forces, which then cause a breaking of the structures and a clogging of the mould. An innovative approach is to combine PVD-coated (physical vapour deposition), laser structured inserts and a variothermal moulding process to create functional mic8iüro structures in a one-step process. Therefore, a PVD-coating is applied after the laser structuring process in order to improve the wear resistance and the anti-adhesive properties against the plastics melt. In a series of moulding trials with polycarbonate (PC) and polymethylmethacrylate (PMMA) using different coated moulds, the mould temperature during injection was varied in the range of the glass transition and the melt temperature of the polymers. Subsequently, the surface topography of the moulded parts is evaluated by digital 3D laser-scanning microscopy. The influence of the moulding parameters and the coating of the mould insert on the moulding accuracy and the demoulding behaviour are being analysed. It is shown that micro structures created by ultra-short pulse laser ablation can be successfully replicated in a variothermal moulding process. Due to the mould coating, significant improvements could be achieved in producing micro structured optical plastics components.

  19. Analytic formulas for magnetron characteristic curves

    SciTech Connect

    Riyopoulos, S.

    1995-12-31

    A closed non-linear set of equations is obtained based on the guiding center fluid model to describe steady-state magnetron operation. Spoke charge effects are included self-consistently, by introducing a mean-field approximation so that the effective AC potential preserves the geometric similarity with the vacuum solutions. New characteristic equations, relating the anode current 1 and the RF power P to the applied DC voltage V at given RF frequency, are obtained. Previously obtained V-I equations disagree with experiments in that (a) anode current and RF power go to zero when the resonance condition V = V{sub s} is met, (b) the operation voltage V is a double-valued function of the current I; there exist two nearly symmetric operation points around V{sub s} at the same current I. Yet magnetrons, and the related crossed-field amplifiers, are known to exhibit stable operation with single valued V-I characteristics well below V{sub s}. Although zero gain at synchronism applies to other microwave devices (TWT`s, FEL`s), experimental results and particle simulations of crossed field devices suggest otherwise. The new formulas show reasonable agreement with experiments.

  20. Analysis of DC magnetron sputtered beryllium films

    SciTech Connect

    Price, C.W.; Hsieh, E.J.; Lindsey, E.F.; Pierce, E.L.; Norberg, J.C.

    1988-10-01

    We are evaluating techniques that alter the columnar grain structure in sputtered beryllium films on fused silica substrates. The films are formed by DC magnetron sputtering, and the columnar structure, which is characteristic of this and most other deposition techniques, is highly detrimental to the tensile strength of the films. Attempts to modify the columnar structure by using RF-biased sputtering combined with nitrogen pulsing have been successful, and this paper describes the analyses of these films. Sputtered beryllium films are quite brittle, and the columnar structure in particular tends to form a distinct intergranular fracture; therefore, the grain structure was analyzed in fractured specimens using the high-resolution capability of a scanning electron microscope (SEM) equipped with a field emission gun (FESEM). Ion microanalysis using secondary-ion mass spectroscopy (SIMS) was conducted on some specimens to determining relative contamination levels introduced by nitrogen pulsing. The capability to perform quantitative SIMS analyses using ion-implanted specimens as standards also is being developed. This work confirms that the structure of DC magnetron sputtered beryllium can be improved significantly with combined nitrogen pulsing and RF-biased sputtering. 8 refs.

  1. Magnetron sputtering for the production of EUV mask blanks

    NASA Astrophysics Data System (ADS)

    Kearney, Patrick; Ngai, Tat; Karumuri, Anil; Yum, Jung; Lee, Hojune; Gilmer, David; Vo, Tuan; Goodwin, Frank

    2015-03-01

    Ion Beam Deposition (IBD) has been the primary technique used to deposit EUV mask blanks since 1995 when it was discovered it could produce multilayers with few defects. Since that time the IBD technique has been extensively studied and improved and is finally approaching usable defectivities. But in the intervening years, the defectivity of magnetron sputtering has been greatly improved. This paper evaluates the suitability of a modern magnetron tool to produce EUV mask blanks and the ability to support HVM production. In particular we show that the reflectivity and uniformity of these tools are superior to current generation IBD tools, and that the magnetron tools can produce EUV films with defect densities comparable to recent best IBD tool performance. Magnetron tools also offer many advantages in manufacturability and tool throughput; however, challenges remain, including transitioning the magnetron tools from the wafer to mask formats. While work continues on quantifying the capability of magnetron sputtering to meet the mask blank demands of the industry, for the most part the remaining challenges do not require any fundamental improvements to existing technology. Based on the recent results and the data presented in this paper there is a clear indication that magnetron deposition should be considered for the future of EUV mask blank production.

  2. Dynamics of Magnetic Insulation Violation in Smooth-bore Magnetrons

    NASA Astrophysics Data System (ADS)

    Agafonov, A. V.; Fedorov, V. M.; Tarakanov, V. P.

    1997-05-01

    The efficiency of large and high-power magnetrons of GW power levels is less than 30% and an inherent pulse-length and repetition rate limitations seems to exist because of use of explosive field emission. Another approach is the development of low voltage high-efficiency magnetrons utilizing a secondary emission magnetron array with high repetition rate. The numerical model of nonstationary nonuniform secondary electron emission from a cathode surface has been developed. The results of the first steps in computer simulations of an electron cloud formation inside a smooth-bore magnetron under the condition of the back-bombardement instability (BBI) are presented. A mechanism of the violation of the magnetic insulation are considered. Calculations have been performed for a coaxial smooth-bore magnetron and for magnetrons with different types of azimuthal inhomogeneities which could help the grow of BBI, and for magnetrons of different aspect ratios. The results of computer simulation are compared with experimental data. The main calculations of the beam dynamics were carried out with PIC-code KARAT.

  3. n-Alkylboronic acid inhibitors reveal determinants of ligand specificity in the quorum-quenching and siderophore biosynthetic enzyme PvdQ.

    PubMed

    Clevenger, Kenneth D; Wu, Rui; Liu, Dali; Fast, Walter

    2014-10-28

    The enzyme PvdQ (E.C. 3.5.1.97) from Pseudomonas aeruginosa is an N-terminal nucleophile hydrolase that catalyzes the removal of an N-myristyl substituent from a biosynthetic precursor of the iron-chelating siderophore pyoverdine. Inhibitors of pyoverdine biosynthesis are potential antibiotics since iron is essential for growth and scarce in most infections. PvdQ also catalyzes hydrolytic amide bond cleavage of selected N-acyl-l-homoserine lactone quorum-sensing signals used by some Gram-negative pathogens to coordinate the transcription of virulence factors. The resulting quorum-quenching activity of PvdQ has potential applications in antivirulence therapies. To inform both inhibitor design and enzyme engineering efforts, a series of n-alkylboronic acid inhibitors of PvdQ was characterized to reveal determinants of ligand selectivity. A simple homologation series results in compounds with Ki values that span from 4.7 mM to 190 pM, with a dependence of ΔGbind values on chain length of -1.0 kcal/mol/CH2. X-ray crystal structures are determined for the PvdQ complexes with 1-ethyl-, 1-butyl-, 1-hexyl-, and 1-octylboronic acids at 1.6, 1.8, 2.0, and 2.1 Å resolution, respectively. The 1-hexyl- and 1-octylboronic acids form tetrahedral adducts with the active-site N-terminal Ser217 in the β-subunit of PvdQ, and the n-alkyl substituents are bound in the acyl-group binding site. The 1-ethyl- and 1-butylboronic acids also form adducts with Ser217 but instead form trigonal planar adducts and extend their n-alkyl substituents into an alternative binding site. These results are interpreted to propose a ligand discrimination model for PvdQ that informs the development of PvdQ-related tools and therapeutics. PMID:25290020

  4. Expression of L-ornithine Ndelta-oxygenase (PvdA) in fluorescent Pseudomonas species: an immunochemical and in silico study.

    PubMed

    Putignani, Lorenza; Ambrosi, Cecilia; Ascenzi, Paolo; Visca, Paolo

    2004-01-01

    Omega-amino acid monooxygenases (EC 1.14.13.-), catalysing the formation of hydroxamate precursors of microbial siderophores (e.g., pyoverdine), have so far eluded structural and biochemical characterisation. Here, the expression of recombinant L-ornithine-Ndelta-oxygenase (PvdA) from Pseudomonas aeruginosa PAO1 is reported. A library of eight monoclonal antibodies (MAbs) directed against PvdA has been generated. Two MAb families recognising the N- and C-terminal regions of PvdA were identified. The MAbs made it possible to demonstrate that 45-48 kDa PvdA homologues are expressed in response to iron limitation by different species and strains of fluorescent pseudomonads. Despite the different degrees in sequence similarity between P. aeruginosa PvdA and putative homologues from Pseudomonas fluorescens, Pseudomonas putida, Pseudomonas syringae, Burkholderia cepacia, and Ralstonia solanacearum, in silico domain scanning predicts an impressive conservation of putative cofactor and substrate binding domains. The MAb library was also used to monitor PvdA expression during the transition of P. aeruginosa from iron-sufficient to iron-deficient growth. PMID:14684153

  5. Phase and Frequency Locked Magnetrons for SRF Sources

    SciTech Connect

    Neubauer, M.; Johnson, R.P.; Popovic, M.; Moretti, A.; /Fermilab

    2009-05-01

    Magnetrons are low-cost highly-efficient microwave sources, but they have several limitations, primarily centered about the phase and frequency stability of their output. When the stability requirements are low, such as for medical accelerators or kitchen ovens, magnetrons are the very efficient power source of choice. But for high energy accelerators, because of the need for frequency and phase stability - proton accelerators need 1-2 degrees source phase stability, and electron accelerators need .1-.2 degrees of phase stability - they have rarely been used. We describe a novel variable frequency cavity technique which will be utilized to phase and frequency lock magnetrons.

  6. The effect of thermal aging on the thermal conductivity of plasma sprayed and EB-PVD thermal barrier coatings

    SciTech Connect

    Dinwiddie, R.B.; Beecher, S.C.; Porter, W.D.; Nagaraj, B.A.

    1996-05-01

    Thermal barrier coatings (TBCs) applied to the hot gas components of turbine engines lead to enhanced fuel efficiency and component reliability. Understanding the mechanisms which control the thermal transport behavior of the TBCs is of primary importance. Electron beam-physical vapor deposition (EV-PVD) and air plasma spraying (APS) are the two most commonly used coating techniques. These techniques produce coatings with unique microstructures which control their performance and stability. The density of the APS coatings was controlled by varying the spray parameters. The low density APS yttria-partially stabilized zirconia (yttria-PSZ) coatings yielded a thermal conductivity that is lower than both the high density APS coatings and the EB-PVD coatings. The thermal aging of both fully and partially stabilized zirconia are compared. The thermal conductivity of the coatings permanently increases upon exposure to high temperatures. These increases are attributed to microstructural changes within the coatings. This increase in thermal conductivity can be modeled using a relationship which depends on both the temperature and time of exposure. Although the EB-PVD coatings are less susceptible to thermal aging effects, results suggest that they typically have a higher thermal conductivity than APS coatings before thermal aging. The increases in thermal conductivity due to thermal aging for plasma sprayed partially stabilized zirconia have been found to be less than for plasma sprayed fully stabilized zirconia coatings.

  7. Microstructural analyses and wear behavior of the cemented carbide tools after laser surface treatment and PVD coating

    NASA Astrophysics Data System (ADS)

    Neves, Davi; Diniz, Anselmo Eduardo; Lima, Milton Sérgio Fernandes

    2013-10-01

    Adhesion is one of the most important characteristics of coating on cutting tools. Poor coating adhesion on the tool favors fragmentation and release of hard abrasive particles between the tool and the workpiece. These particles interact with the surfaces of the tool, accelerating its wear and decreasing tool life. One possible solution is the use of laser texturing prior to coating in order to achieve a desired surface topography with enhanced adhesion properties. In the texturing, a high-frequency short-pulse laser changes surface characteristics, generating resolidified material and selective vaporization. This work evaluated the effectiveness of laser texturing in improving the substrate-coating adhesion of PVD coated cemented carbide tools. To this end, the substrates were textured with a Nd:YAG laser, in four different intensities, and then coated with a PVD TiAlN film. To ascertain the effectiveness of laser texturing, Rockwell C indentation and turning experiments were performed on both textured tools and conventional unlasered tools. The PVD coated laser-textured tool showed better performance in the indentation and turning tests than the standard tools. A comparative evaluation of tool wear mechanisms indicated that texturing did not change the wear mechanisms, but altered their importance to tool wear. The anchoring provided by the higher roughness of the textured surface increased the adhesion of the coating on the substrate, thus increasing tool life. Additionally, the chemical modification of the carbide grains due to the laser heating might be responsible for an enhanced adhesion between coating and substrate.

  8. Tribological Properties of PVD Carbon-Copper Composite Films Reinforced by Titanium

    NASA Astrophysics Data System (ADS)

    Lungevics, J.; Leitans, A.; Rudzitis, J.; Bulahs, N.; Nazarovs, P.; Kovalenko, V.

    2016-02-01

    Carbon-copper composite coatings reinforced with titanium were deposited using high power magnetron sputtering technique. Tribological and metrological tests were performed using Taylor Hobson Talysurf Intra 50 measuring equipment and CSM Instruments ball-on-disk type tribometer. Friction coefficient and wear rate were determined at 2N, 4N, 6N loads. It was revealed that friction coefficient decreased at a higher Ti concentration, which was particularly expressed at bigger applied loads. However, wear volume values tended to increase in the beginning, till Ti concentration reached about 11 %, but then decreased, thus providing better nanocoating wear resistance.

  9. The Qualitative Magnetron -- Part of a Computer-Based Tutorial

    NASA Astrophysics Data System (ADS)

    Mead, William C.; Browman, Andrew A.; Silbar, Richard R.

    1998-10-01

    The magnetron is a ubiquitous electromagnetic device, widely used in radar and microwave oven applications. However, it is not usually a part of a general physics curriculum and many practicing physicists have only a vague notion of how it works. We are developing a set of computer-based, self-paced tutorials on particle accelerators that targets a broad audience, including undergraduate science majors and industrial technicians. The magnetron is covered in our module Motion in Electromagnetic Fields as an example of a crossed-field device. We originally expected this to be an advanced topic at the graduate student level. We were pleased to find we could give a satisfying description of how the magnetron works at an introductory level, using pictures and words, without equations. This talk will present our qualitative discussion of the magnetron, direct to you from the computer screen.

  10. Performance and test results of a regulated magnetron pulser

    SciTech Connect

    Rose, C.R.; Warren, D.S.

    1998-12-31

    This paper describes the test results and performance of a 5.0-kV, 750-mA, regulated current pulser used to drive an Hitachi model 2M130 2,425-MHz magnetron. The magnetron is used to modulate the plasma in a particle accelerator injector. In this application, precise and stable rf power is crucial to extract a stable and accurate particle beam. A 10-kV high-voltage triode vacuum tube with active feedback is used to control the magnetron current and output rf power. The pulse width may be varied from as little as ten microseconds to continuous duty by varying the width of a supplied gate pulse. The output current level can be programmed between 10 and 750 mA. Current regulation and accuracy are better than 1%. The paper discusses the overall performance of the pulser and magnetron including anode current and rf power waveforms, linearity compliance, and vacuum tube performance.

  11. Ordering of Fine Particles in a Planar Magnetron Plasma

    SciTech Connect

    Hayashi, Y.; Takahashi, K.; Totsuji, H.; Ishihara, O.; Sato, N.; Watanabe, Y.; Adachi, S.

    2008-09-07

    Fine particles injected in a planar magnetron were pushed upward by diffusible plasma, leading to being suspended by the force balance with the gravity and forming three-dimensional structures on the two-dimensional structure formed by particle strings.

  12. Magnetron discharge sputtering for fabrication of nanogradient optical coatings

    NASA Astrophysics Data System (ADS)

    Volpian, O. D.; Kuzmichev, A. I.; Ermakov, G. F.; Krikunov, A. I.; Obod, Yu A.; Silin, N. V.; Shkatula, S. V.

    2015-11-01

    The technology of the middle frequency pulse reactive magnetron sputtering for fabrication of nanogradient optical coatings with smooth variation of refractive index was developed and studied. The technology is based on programmable motion of a substrate over two magnetrons with targets of different materials. The feature of the deposition process is a constant composition of reactive gas medium and an invariable magnetron operation mode. To realize this technology, an automatic computer-controlled sputtering system additionally comprising a gas discharge activator of reactive gas (oxygen) and an in situ optical monitor- spectrovisor has been built. The dielectric oxide-based nanogradient coatings of photon-barrier type were successfully fabricated. The obtained results confirm the high potential of the middle frequency pulse reactive magnetron sputtering of silicon and metal targets for fabrication of nanogradient dielectric optical coatings with excellent properties.

  13. On the evolution of film roughness during magnetron sputtering deposition

    SciTech Connect

    Turkin, A. A.; Pei, Y. T.; Shaha, K. P.; Chen, C. Q.; Vainshtein, D. I.; De Hosson, J. Th. M.

    2010-11-15

    The effect of long-range screening on the surface morphology of thin films grown with pulsed-dc (p-dc) magnetron sputtering is studied. The surface evolution is described by a stochastic diffusion equation that includes the nonlocal shadowing effects in three spatial dimensions. The diffusional relaxation and the angular distribution of the incident particle flux strongly influence the transition to the shadowing growth regime. In the magnetron sputtering deposition the shadowing effect is essential because of the configuration of the magnetron system (finite size of sputtered targets, rotating sample holder, etc.). A realistic angular distribution of depositing particles is constructed by taking into account the cylindrical magnetron geometry. Simulation results are compared with the experimental data of surface roughness evolution during 100 and 350 kHz p-dc deposition, respectively.

  14. Rotating cylindrical magnetron sputtering: Simulation of the reactive process

    SciTech Connect

    Depla, D.; Mahieu, S.; Van Aeken, K.; Leroy, W. P.; Haemers, J.; De Gryse, R.; Li, X. Y.; Bogaerts, A.

    2010-06-15

    A rotating cylindrical magnetron consists of a cylindrical tube, functioning as the cathode, which rotates around a stationary magnet assembly. In stationary mode, the cylindrical magnetron behaves similar to a planar magnetron with respect to the influence of reactive gas addition to the plasma. However, the transition from metallic mode to poisoned mode and vice versa depends on the rotation speed. An existing model has been modified to simulate the influence of target rotation on the well known hysteresis behavior during reactive magnetron sputtering. The model shows that the existing poisoning mechanisms, i.e., chemisorption, direct reactive ion implantation and knock on implantation, are insufficient to describe the poisoning behavior of the rotating target. A better description of the process is only possible by including the deposition of sputtered material on the target.

  15. Factors determining the efficiency of magnetron sputtering. Optimization criteria

    NASA Astrophysics Data System (ADS)

    Rogov, A. V.; Kapustin, Yu. V.; Martynenko, Yu. V.

    2015-02-01

    We report on the results of experimental study of the dependence of sputtering energy efficiency K w in a dc planar magnetron sputtering setup on the discharge power, working gas pressure, magnetic field, cathode erosion depth, and the structure of the gas puffing system and anode. We propose that this parameter be used for comparing the degree of perfection of the magnetron design irrespective of the magnetron size and structural features. The results of measurements of K w in sputtering of Al, Ti, Cr, Cu, Zn, Zr, Nb, Mo, Ag, In, Sn, Ta, W, Pt, and Au are considered. The optimization criterion is worked out for the magnetic system of the magnetron, which ensures the minimal working pressure and the maximal sputtering rate for the cathode. The results are analyzed theoretically.

  16. Satellite power system (SPS) magnetron tube assessment study

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Taks performed to extend the data base and to define a technology development program for the magnetron directional amplifier for the SPS are reviewed. These include: (1) demonstrating the tracking of phase and amplitude of the microwave output to phase and amplitude references; (2) expanding the range of power over which the directional amplifier will operate; (3)recognizing the importance of amplitude control in overall system design and in simplifying power conditioning; (4) developing a preliminary design for the overall architecture of the power module; (5) demonstrating magnetron starting using the amplitude control system; (6) mathematically modelling and performing a computerized study of the pyrolytic graphite radiating fin; (7) defining the mass of the magnetic circuit for the SPS tube; (8) noise measurement; (9) achieving harmonic suppression by notch reflection filters; (10) estimating the mass of the transmitting antenna; (11) developing a magnetron package with power generation, phase control, and power condition functions; and (12) projecting magnetron package characteristics.

  17. Substrate heating and cooling during magnetron sputtering of copper target

    NASA Astrophysics Data System (ADS)

    Shapovalov, Viktor I.; Komlev, Andrey E.; Bondarenko, Anastasia S.; Baykov, Pavel B.; Karzin, Vitaliy V.

    2016-02-01

    Heating and cooling processes of the substrate during the DC magnetron sputtering of the copper target were investigated. The sensitive element of a thermocouple was used as a substrate. It was found, that the heat outflow rate from the substrate is lower when the magnetron is turned off rather than when it is turned on. Furthermore, the heating rate, the ultimate temperature, and the heat outflow rate related to the deposition of copper atoms are directly proportional to the discharge current density.

  18. 3D Magnetron simulation with CST STUDIO SUITE

    SciTech Connect

    Balk, Monika C.

    2011-07-01

    The modeling of magnetrons compared to other tubes is more difficult since it requires 3D modeling rather than a 2D investigation. This is not only due to the geometry which can include complicated details to be modeled in 3D but also due to the interaction process itself. The electric field, magnetic field and particle movement span a 3D space. In this paper 3D simulations of a strapped magnetron with CSTSTUDIO SUITE{sup TM} are presented. (author)

  19. Effect of Bond Coat Materials on Thermal Fatigue Failure of EB-PVD Thermal Barrier Coatings

    NASA Astrophysics Data System (ADS)

    Yamagishi, Satoshi; Okazaki, Masakazu; Sakaguchi, Motoki; Matsubara, Hideaki

    Effect of MCrAlY bond coat alloy systems on thermal fatigue failure of thermal barrier coatings (TBCs) was investigated, where the TBC specimen consisted of Ni-based superalloy IN738LC substrate, bond coat, and 8 wt.% Y2O3-stabilized ZrO2 (YSZ) top coat. The top coat was fabricated by EB-PVD method with 250 μm in thickness. Three kinds of MCrAlY alloys were studied as the bond coat material. Employing the originally developed test equipment, thermal fatigue tests were carried out, by applying thermal cycles between 400 and 950°C in air. Special attention was paid not only to the failure life of the TBC specimen, but also the underlying failure mechanisms. The experimental results clearly demonstrated that the effect of MCrAlY bond coat alloys on the thermal fatigue life was very significant. Some discussions were made on the experimental results based on the measurements of mechanical and metallurgical properties of the bond coat alloys: i.e., elastic stiffness, thermal expansion coefficient and high temperature oxidation resistance.

  20. Evaluation of Osseous Integration of PVD-Silver-Coated Hip Prostheses in a Canine Model

    PubMed Central

    Hauschild, Gregor; Hardes, Jendrik; Gosheger, Georg; Blaske, Franziska; Wehe, Christoph; Karst, Uwe; Höll, Steffen

    2015-01-01

    Infection associated with biomaterials used for orthopedic prostheses remains a serious complication in orthopedics, especially tumor surgery. Silver-coating of orthopedic (mega)prostheses proved its efficiency in reducing infections but has been limited to surface areas exposed to soft tissues due to concerns of silver inhibiting osseous integration of cementless stems. To close this gap in the bactericidal capacity of silver-coated orthopedic prostheses extension of the silver-coating on surface areas intended for osseous integration seems to be inevitable. Our study reports about a PVD- (physical-vapor-deposition-) silver-coated cementless stem in a canine model for the first time and showed osseous integration of a silver-coated titanium surface in vivo. Radiological, histological, and biomechanical analysis revealed a stable osseous integration of four of nine stems implanted. Silver trace elemental concentrations in serum did not exceed 1.82 parts per billion (ppb) and can be considered as nontoxic. Changes in liver and kidney functions associated with the silver-coating could be excluded by blood chemistry analysis. This was in accordance with very limited metal displacement from coated surfaces observed by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) 12 months after implantation. In conclusion our results represent a step towards complete bactericidal silver-coating of orthopedic prostheses. PMID:25695057

  1. Mg Content Dependence of EML-PVD Zn-Mg Coating Adhesion on Steel Strip

    NASA Astrophysics Data System (ADS)

    Jung, Woo Sung; Lee, Chang Wook; Kim, Tae Yeob; De Cooman, Bruno C.

    2016-09-01

    The effect of coating thickness and Mg concentration on the adhesion strength of electromagnetic levitation physical vapor deposited Zn-Mg alloy coatings on steel strip was investigated. The phase fraction of Zn, Mg2Zn11, and MgZn2 was determined for a coating Mg concentration in the 0 to 15 wt pct range. Coatings with a Mg content less than 5 pct consisted of an Zn and Mg2Zn11 phase mixture. The coatings showed good adhesion strength and ductile fracture behavior. Coatings with a higher Mg concentration, which consisted of a Mg2Zn11 and MgZn2 phase mixture, had a poor adhesion strength and a brittle fracture behavior. The adhesion strength of PVD Zn-Mg alloy coatings was found to be related to the pure Zn phase fraction. The effect of coating thickness on adhesion strength was found to be negligible. The microstructure of the interface between steel and Zn-Mg alloy coatings was investigated in detail by electron microscopy, electron diffraction, and atom probe tomography.

  2. Evaluation of osseous integration of PVD-silver-coated hip prostheses in a canine model.

    PubMed

    Hauschild, Gregor; Hardes, Jendrik; Gosheger, Georg; Stoeppeler, Sandra; Ahrens, Helmut; Blaske, Franziska; Wehe, Christoph; Karst, Uwe; Höll, Steffen

    2015-01-01

    Infection associated with biomaterials used for orthopedic prostheses remains a serious complication in orthopedics, especially tumor surgery. Silver-coating of orthopedic (mega)prostheses proved its efficiency in reducing infections but has been limited to surface areas exposed to soft tissues due to concerns of silver inhibiting osseous integration of cementless stems. To close this gap in the bactericidal capacity of silver-coated orthopedic prostheses extension of the silver-coating on surface areas intended for osseous integration seems to be inevitable. Our study reports about a PVD- (physical-vapor-deposition-) silver-coated cementless stem in a canine model for the first time and showed osseous integration of a silver-coated titanium surface in vivo. Radiological, histological, and biomechanical analysis revealed a stable osseous integration of four of nine stems implanted. Silver trace elemental concentrations in serum did not exceed 1.82 parts per billion (ppb) and can be considered as nontoxic. Changes in liver and kidney functions associated with the silver-coating could be excluded by blood chemistry analysis. This was in accordance with very limited metal displacement from coated surfaces observed by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) 12 months after implantation. In conclusion our results represent a step towards complete bactericidal silver-coating of orthopedic prostheses. PMID:25695057

  3. Mg Content Dependence of EML-PVD Zn-Mg Coating Adhesion on Steel Strip

    NASA Astrophysics Data System (ADS)

    Jung, Woo Sung; Lee, Chang Wook; Kim, Tae Yeob; De Cooman, Bruno C.

    2016-07-01

    The effect of coating thickness and Mg concentration on the adhesion strength of electromagnetic levitation physical vapor deposited Zn-Mg alloy coatings on steel strip was investigated. The phase fraction of Zn, Mg2Zn11, and MgZn2 was determined for a coating Mg concentration in the 0 to 15 wt pct range. Coatings with a Mg content less than 5 pct consisted of an Zn and Mg2Zn11 phase mixture. The coatings showed good adhesion strength and ductile fracture behavior. Coatings with a higher Mg concentration, which consisted of a Mg2Zn11 and MgZn2 phase mixture, had a poor adhesion strength and a brittle fracture behavior. The adhesion strength of PVD Zn-Mg alloy coatings was found to be related to the pure Zn phase fraction. The effect of coating thickness on adhesion strength was found to be negligible. The microstructure of the interface between steel and Zn-Mg alloy coatings was investigated in detail by electron microscopy, electron diffraction, and atom probe tomography.

  4. Surface properties of Mo-implanted PVD TiN coatings using MEVVA source

    NASA Astrophysics Data System (ADS)

    Tian, Bin; Yue, Wen; Fu, Zhiqiang; Gu, Yanhong; Wang, Chengbiao; Liu, Jiajun

    2013-09-01

    To further improve the tribological properties of TiN coatings used on mechanical parts, Mo ions were implanted into PVD TiN coatings with Metal Vapor Vacuum Arc (MEVVA) source at the implantation dose as high as 1 × 1018 ions/cm2. Surface morphology, microstructures, and nano-hardness of TiN coatings were investigated by optical profilometer, X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), and Nano Indenter System. The tribological properties were investigated on a ball-on-disk friction and wear tester. The XRD results demonstrated that the diffraction peak of Ti2N appeared in the Mo-implanted TiN coatings. However, there was obvious decrease of nano-hardness due to the soft Molybdenum phase and its oxides. It was approved that Mo-implanted TiN coatings could greatly improve their tribological properties and that the implantation at dose of 1 × 1018 ions/cm2 could result in much lower friction coefficient. The existence of soft molybdenum, lubricious molybdenum oxides and titanium oxides resulted in the remarkable reducing of the friction coefficient of TiN coatings with Mo-implantation.

  5. Characterization of Surface Properties and Microstructure of PVD-TiN Films Using Mevva Ion Implantation

    NASA Astrophysics Data System (ADS)

    Yang, J. H.; Cheng, M. F.; Luo, X. D.; Zhang, T. H.

    The PVD-TiN film was implanted with titanium ions and the improvement in surface wear resistance was investigated. Ti ion implantation was done using a metal vapor vacuum arc (MEVVA) ion source with an implantation dose of 2 × 1016 ions/cm2 and at an extraction voltage of 48 kV. The wear characteristics of the implanted zone was measured and compared to the performance of the unimplanted zone by a pin-on-disc apparatus and an optical interference microscope. The structure of the implanted zone and unimplanted one was observed by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). A dynamic TRIM called TRIDYN was used to calculate the concentration depth profile of implanted Ti in TiN to investigate the profile of multi-charge state ions. The results showed that the improved wear resistance of the TiN film was mainly due to the presence of nano-order TiN crystal grains after Ti ion implantation.

  6. Effect of Hf Additions to Pt Aluminide Bond Coats on EB-PVD TBC Life

    NASA Technical Reports Server (NTRS)

    Nesbitt, James; Nagaraj, Ben; Williams, Jeffrey

    2000-01-01

    Small Hf additions were incorporated into a Pt aluminide coating during chemical vapor deposition (CVD) on single crystal RENE N5 substrates. Standard yttria-stabilized zirconia top coats were subsequently deposited onto the coated substrates by electron beam-physical vapor deposition (EB-PVD). The coated substrates underwent accelerated thermal cycle testing in a furnace at a temperature in excess of 1121 C (2050 F) (45 minute hot exposure, 15 minute cool to approximately 121 C (250 F)) until the thermal barrier coating (TBC) failed by spallation. Incorporating Hf in the bond coat increased the TBC life by slightly more than three times that of a baseline coating without added Hf. Scanning electron microscopy of the spalled surfaces indicated that the presence of the Hf increased the adherence of the thermally grown alumina to the Pt aluminide bond coat. The presence of oxide pegs growing into the coating from the thermally grown alumina may also partially account for the improved TBC life by creating a near-surface layer with a graded coefficient of thermal expansion.

  7. Evaluation of Antibacterial Activity of Titanium Surface Modified by PVD/PACVD Process.

    PubMed

    Ji, Min-Kyung; Lee, Min-Joo; Park, Sang-Won; Lee, Kwangmin; Yun, Kwi-Dug; Kim, Hyun-Seung; Oh, Gye-Jeong; Kim, Ji-Hyun; Lim, Hyun-Pil

    2016-02-01

    The aim of this study was to evaluate the response of Streptococcus mutans (S. mutans) via crystal violet staining assay on titanium surface modified by physical vapor deposition/plasma assisted chemical vapor deposition process. Specimens were divided into the following three groups: polished titanium (control group), titanium modified by DC magnetron sputtering (group TiN-Ti), and titanium modified by plasma nitriding (group N-Ti). Surface characteristics of specimens were observed by using nanosurface 3D optical profiler and field emission scanning electron microscope. Group TiN-Ti showed TiN layer of 1.2 microm in thickness. Group N-Ti was identified as plasma nitriding with X-ray photoelectron spectroscopy. Roughness average (Ra) of all specimens had values < or = 0.2 microm (the threshold Ra), which had no effect on bacterial adhesion. No significant difference of S. mutans adhesion was found between the surfaces of control, TiN-Ti, and N-Ti (P > 0.05). Within the process condition of this study, modified titanium surfaces by DC magnetron sputtering and plasma nitriding did not influence the adhesion of S. mutans. PMID:27433640

  8. Cloning and nucleotide sequence of the pvdA gene encoding the pyoverdin biosynthetic enzyme L-ornithine N5-oxygenase in Pseudomonas aeruginosa.

    PubMed Central

    Visca, P; Ciervo, A; Orsi, N

    1994-01-01

    The enzyme L-ornithine N5-oxygenase catalyzes the hydroxylation of L-ornithine (L-Orn), which represents an early step in the biosynthesis of the peptidic moiety of the fluorescent siderophore pyoverdin in Pseudomonas aeruginosa. A gene bank of DNA from P. aeruginosa PAO1 (ATCC 15692) was constructed in the broad-host-range cosmid pLAFR3 and mobilized into the L-Orn N5-oxygenase-defective (pvdA) P. aeruginosa mutant PALS124. Screening for fluorescent transconjugants made it possible to identify the trans-complementing cosmid pPV4, which was able to restore pyoverdin synthesis and L-Orn N5-oxygenase activity in the pvdA mutant PALS124. The 17-kb PAO1 DNA insert of pPV4 contained at least two genetic determinants involved in pyoverdin synthesis, i.e., pvdA and pvdC4, as shown by complementation analysis of a set of mutants blocked in different steps of the pyoverdin biosynthetic pathway. Deletion analysis, subcloning, and transposon mutagenesis enabled us to locate the pvdA gene in a minimum DNA fragment of 1.7 kb flanked by two SphI restriction sites. Complementation of the pvdA mutation was under stringent iron control; both pyoverdin synthesis and L-Orn N5-oxygenase activity were undetectable in cells of the trans-complemented mutant which had been grown in the presence of 100 microM FeCl3. The entire nucleotide sequence of the pvdA gene, from which the primary structure of the encoded polypeptide was deduced, was determined. The pvdA structural gene is 1,278 bp; the cloned DNA fragment contains at the 5' end of the gene a putative ribosome-binding site but apparently lacks known promoterlike sequences. The P. aeruginosa L-Orn N5-oxygenase gene codes for a 426-amino-acid peptide with a predicted molecular mass of 47.7 kDa and an isoelectric point of 8.1. The enzyme shows approximately 50% homology with functional analogs, i.e., L-lysine N6-hydroxylase of aerobactin-producing Escherichia coli and L-Orn N5-oxygenase of ferrichrome-producing Ustilago maydis. The pvd

  9. Multi-cathode unbalanced magnetron sputtering systems

    NASA Technical Reports Server (NTRS)

    Sproul, William D.

    1991-01-01

    Ion bombardment of a growing film during deposition is necessary in many instances to ensure a fully dense coating, particularly for hard coatings. Until the recent advent of unbalanced magnetron (UBM) cathodes, reactive sputtering had not been able to achieve the same degree of ion bombardment as other physical vapor deposition processes. The amount of ion bombardment of the substrate depends on the plasma density at the substrate, and in a UBM system the amount of bombardment will depend on the degree of unbalance of the cathode. In multi-cathode systems, the magnetic fields between the cathodes must be linked to confine the fast electrons that collide with the gas atoms. Any break in this linkage results in electrons being lost and a low plasma density. Modeling of the magnetic fields in a UBM cathode using a finite element analysis program has provided great insight into the interaction between the magnetic fields in multi-cathode systems. Large multi-cathode systems will require very strong magnets or many cathodes in order to maintain the magnetic field strength needed to achieve a high plasma density. Electromagnets offer the possibility of independent control of the plasma density. Such a system would be a large-scale version of an ion beam enhanced deposition (IBED) system, but, for the UBM system where the plasma would completely surround the substrate, the acronym IBED might now stand for Ion Blanket Enhanced Deposition.

  10. 3-D Printed High Power Microwave Magnetrons

    NASA Astrophysics Data System (ADS)

    Jordan, Nicholas; Greening, Geoffrey; Exelby, Steven; Gilgenbach, Ronald; Lau, Y. Y.; Hoff, Brad

    2015-11-01

    The size, weight, and power requirements of HPM systems are critical constraints on their viability, and can potentially be improved through the use of additive manufacturing techniques, which are rapidly increasing in capability and affordability. Recent experiments on the UM Recirculating Planar Magnetron (RPM), have explored the use of 3-D printed components in a HPM system. The system was driven by MELBA-C, a Marx-Abramyan system which delivers a -300 kV voltage pulse for 0.3-1.0 us, with a 0.15-0.3 T axial magnetic field applied by a pair of electromagnets. Anode blocks were printed from Water Shed XC 11122 photopolymer using a stereolithography process, and prepared with either a spray-coated or electroplated finish. Both manufacturing processes were compared against baseline data for a machined aluminum anode, noting any differences in power output, oscillation frequency, and mode stability. Evolution and durability of the 3-D printed structures were noted both visually and by tracking vacuum inventories via a residual gas analyzer. Research supported by AFOSR (grant #FA9550-15-1-0097) and AFRL.

  11. On reactive high power impulse magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.

    2016-01-01

    High power impulse magnetron sputtering (HiPIMS) is an ionized physical vapor deposition (IPVD) technique that is particularly promising for reactive sputtering applications. However, there are few issues that have to be resolved before the full potential of this technique can be realized. Here we give an overview of the key experimental findings for the reactive HiPIMS discharge. An increase in the discharge current is commonly observed with increased partial pressure of the reactive gas or decreased repetition pulse frequency. There are somewhat conflicting claims regarding the hysteresis effect in the reactive HiPIMS discharge as some report reduction or elimination of the hysteresis effect while others claim a feedback control is essential. The ion energy distribution of the metal ion and the atomic ion of the reactive gas are similar and extend to very high energies while the ion energy distribution of the working gas and the molecular ion of the reactive gas are similar and are much less energetic.

  12. Thick beryllium coatings by magnetron sputtering

    SciTech Connect

    Wu, H; Nikroo, A; Youngblood, K; Moreno, K; Wu, D; Fuller, T; Alford, C; Hayes, J; Detor, A; Wong, M; Hamza, A; van Buuren, T; Chason, E

    2011-04-14

    Thick (>150 {micro}m) beryllium coatings are studied as an ablator material of interest for fusion fuel capsules for the National Ignition Facility (NIF). As an added complication, the coatings are deposited on mm-scale spherical substrates, as opposed to flats. DC magnetron sputtering is used because of the relative controllability of the processing temperature and energy of the deposits. We used ultra small angle x-ray spectroscopy (USAXS) to characterize the void fraction and distribution along the spherical surface. We investigated the void structure using a combination focused ion beam (FIB) and scanning electron microscope (SEM), along with transmission electron microscopy (TEM). Our results show a few volume percent of voids and a typical void diameter of less than two hundred nanometers. Understanding how the stresses in the deposited material develop with thickness is important so that we can minimize film cracking and delamination. To that end, an in-situ multiple optical beam stress sensor (MOSS) was used to measure the stress behavior of thick Beryllium coatings on flat substrates as the material was being deposited. We will show how the film stress saturates with thickness and changes with pressure.

  13. Anisotropy of the electron component in a cylindrical magnetron discharge. II. Application to real magnetron discharge.

    PubMed

    Porokhova, I A; Golubovskii, Yu B; Behnke, J F

    2005-06-01

    The physical processes occurring in electrode regions and the positive column of a cylindrical magnetron discharge in crossed electric and magnetic fields are investigated based on the solution of the Boltzmann kinetic equation by a multiterm decomposition of the electron phase space distribution function in terms of spherical tensors. The influence of the distribution function anisotropy on the absolute values and radial profiles of the electron density and rates of various transport and collision processes is analyzed. The spiral lines for the directed particle and energy transport are obtained to illustrate the anisotropy effects in dependence on the magnetic field. The electron equipressure surfaces are constructed in the form of ellipsoids of pressure and their transformation in the cathode and anode regions is studied. A strong anisotropy of the energy flux tensor in contrast to a weak anisotropy of the momentum flux density tensor is found. Particular results are obtained for the cylindrical magnetron discharge in argon at pressure 3 Pa, current 200 mA, and magnetic fields ranging within 100 and 400 G. PMID:16089880

  14. Tracking the Magnetron Motion in FT-ICR Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Jertz, Roland; Friedrich, Jochen; Kriete, Claudia; Nikolaev, Evgeny N.; Baykut, Gökhan

    2015-08-01

    In Fourier transform ion cyclotron resonance spectrometry (FT-ICR MS) the ion magnetron motion is not usually directly measured, yet its contribution to the performance of the FT-ICR cell is important. Its presence is manifested primarily by the appearance of even-numbered harmonics in the spectra. In this work, the relationship between the ion magnetron motion in the ICR cell and the intensities of the second harmonic signal and its sideband peak in the FT-ICR spectrum is studied. Ion motion simulations show that during a cyclotron motion excitation of ions which are offset to the cell axis, a position-dependent radial drift of the cyclotron center takes place. This radial drift can be directed outwards if the ion is initially offset towards one of the detection electrodes, or it can be directed inwards if the ion is initially offset towards one of the excitation electrodes. Consequently, a magnetron orbit diameter can increase or decrease during a resonant cyclotron excitation. A method has been developed to study this behavior of the magnetron motion by acquiring a series of FT-ICR spectra using varied post-capture delay (PCD) time intervals. PCD is the delay time after the capture of the ions in the cell before the cyclotron excitation of the ion is started. Plotting the relative intensity of the second harmonic sideband peak versus the PCD in each mass spectrum leads to an oscillating "PCD curve". The position and height of minima and maxima of this curve can be used to interpret the size and the position of the magnetron orbit. Ion motion simulations show that an off-axis magnetron orbit generates even-numbered harmonic peaks with sidebands at a distance of one magnetron frequency and multiples of it. This magnetron offset is due to a radial offset of the electric field axis versus the geometric cell axis. In this work, we also show how this offset of the radial electric field center can be corrected by applying appropriate DC correction voltages to the

  15. Influence of high power impulse magnetron sputtering plasma ionization on the microstructure of TiN thin films

    NASA Astrophysics Data System (ADS)

    Ehiasarian, A. P.; Vetushka, A.; Gonzalvo, Y. Aranda; Sáfrán, G.; Székely, L.; Barna, P. B.

    2011-05-01

    HIPIMS (High Power Impulse Magnetron Sputtering) discharge is a new PVD technology for the deposition of high-quality thin films. The deposition flux contains a high degree of metal ionization and nitrogen dissociation. The microstructure of HIPIMS-deposited nitride films is denser compared to conventional sputter technologies. However, the mechanisms acting on the microstructure, texture and properties have not been discussed in detail so far. In this study, the growth of TiN by HIPIMS of Ti in mixed Ar and N2 atmosphere has been investigated. Varying degrees of metal ionization and nitrogen dissociation were produced by increasing the peak discharge current (Id) from 5 to 30 A. The average power was maintained constant by adjusting the frequency. Mass spectrometry measurements of the deposition flux revealed a high content of ionized film-forming species, such as Ti1+, Ti2+ and atomic nitrogen N1+. Ti1+ ions with energies up to 50 eV were detected during the pulse with reducing energy in the pulse-off times. Langmuir probe measurements showed that the peak plasma density during the pulse was 3 × 1016 m-3. Plasma density, and ion flux ratios of N1+: N21+ and Ti1+: Ti0 increased linearly with peak current. The ratios exceeded 1 at 30 A. TiN films deposited by HIPIMS were analyzed by X-ray diffraction, and transmission electron microscopy. At high Id, N1+: N21+> 1 and Ti1+: Ti0> 1 were produced; a strong 002 texture was present and column boundaries in the films were atomically tight. As Id reduced and N1+: N21+ and Ti1+: Ti0 dropped below 1, the film texture switched to strong 111 with a dense structure. At very low Id, porosity between columns developed. The effects of the significant activation of the deposition flux observed in the HIPIMS discharge on the film texture, microstructure, morphology and properties are discussed.

  16. Analysis and experiments of self-injection magnetron

    NASA Astrophysics Data System (ADS)

    Yi, Zhang; Wen-Jun, Ye; Ping, Yuan; Huan-Cheng, Zhu; Yang, Yang; Ka-Ma, Huang

    2016-04-01

    Magnetrons are widely used in microwave-based industrial applications, which are rapidly developing. However, the coupling between their output frequency and power as well as their wideband spectra restricts their further application. In this work, the output frequency and power of a magnetron are decoupled by self-injection. Moreover, the spectral bandwidth is narrowed, and the phase noise is reduced for most loop phase values. In order to predict the frequency variation with loop phase and injection ratio, a theoretical model based on a circuit equivalent to the magnetron is developed. Furthermore, the developed model also shows that the self-injection magnetron is stabler than the free-running magnetron and that the magnetron’s phase noise can be reduced significantly for most loop phase values. Experimental results confirm the conclusions obtained using the proposed model. Project supported by the National Basic Research Program of China (Grant No. 2013CB328902) and the National Natural Science Foundation of China (Grant No. 61501311).

  17. Relation of thermal conductivity with process induced anisotropic void system in EB-PVD PYSZ thermal barrier coatings.

    SciTech Connect

    Renteria, A. F.; Saruhan, B.; Ilavsky, J.; German Aerospace Center

    2007-01-01

    Thermal barrier coatings (TBCs) deposited by Electron-beam physical deposition (EB-PVD) protect the turbine blades situated at the high pressure sector of the aircraft and stationary turbines. It is an important task to uphold low thermal conductivity in TBCs during long-term service at elevated temperatures. One of the most promising methods to fulfil this task is to optimize the properties of PYSZ-based ,TBC by tailoring its microstructure. Thermal conductivity of the EB-PVD produced PYSZ TBCs is influenced mainly by the size, shape, orientation and volume of the various types of porosity present in the coatings. These pores can be classified as open (inter-columnar and between feather arms gaps) and closed (intra-columnar pores). Since such pores are located within the three-dimensionally deposited columns and enclose large differences in their sizes, shapes, distribution and anisotropy, the accessibility for their characterization is very complex and requires the use of sophisticated methods. In this work, three different EB-PVD TBC microstructures were manufactured by varying the process parameters, yielding various characteristics of their pores. The corresponding thermal conductivities in as-coated state and after ageing at 1100C/1h and 100h were measured via Laser Flash Analysis Method (LFA). The pore characteristics and their individual effect on the thermal conductivity are analysed by USAXS which is supported by subsequent modelling and LFA methods, respectively. Evident differences in the thermal conductivity values of each microstructure were found in as-coated and aged conditions. In summary, broader columns introduce higher values in thermal conductivity. In general, thermal conductivity increases after ageing for all three investigated microstructures, although those with initial smaller pore surface area show smaller changes.

  18. Relation of Thermal Conductivity with Process Induced Anisotropic Void Systems in EB-PVD PYSZ Thermal Barrier Coatings

    SciTech Connect

    Renteria, A. Flores; Saruhan-Brings, B.; Ilavsky, J.

    2008-03-03

    Thermal barrier coatings (TBCs) deposited by Electron-beam physical deposition (EB-PVD) protect the turbine blades situated at the high pressure sector of the aircraft and stationary turbines. It is an important task to uphold low thermal conductivity in TBCs during long-term service at elevated temperatures. One of the most promising methods to fulfil this task is to optimize the properties of PYSZ-based TBC by tailoring its microstructure. Thermal conductivity of the EB-PVD produced PYSZ TBCs is influenced mainly by the size, shape, orientation and volume of the various types of porosity present in the coatings. These pores can be classified as open (inter-columnar and between feather arms gaps) and closed (intra-columnar pores). Since such pores are located within the three-dimensionally deposited columns and enclose large differences in their sizes, shapes, distribution and anisotropy, the accessibility for their characterization is very complex and requires the use of sophisticated methods. In this work, three different EB-PVD TBC microstructures were manufactured by varying the process parameters, yielding various characteristics of their pores. The corresponding thermal conductivities in as-coated state and after ageing at 11000C/1h and 100h were measured via Laser Flash Analysis Method (LFA). The pore characteristics and their individual effect on the thermal conductivity are analysed by USAXS which is supported by subsequent modelling and LFA methods, respectively. Evident differences in the thermal conductivity values of each microstructure were found in as-coated and aged conditions. In summary, broader columns introduce higher values in thermal conductivity. In general, thermal conductivity increases after ageing for all three investigated microstructures, although those with initial smaller pore surface area show smaller changes.

  19. Development of Production PVD-AIN Buffer Layer System and Processes to Reduce Epitaxy Costs and Increase LED Efficiency

    SciTech Connect

    Cerio, Frank

    2013-09-14

    was analyzed and improvements implemented to the Veeco PVD-AlN prototype system to establish a specification and baseline PVD-AlN films on sapphire and in parallel the evaluation of PVD AlN on silicon substrates began. In Phase II of the project a Beta tool based on a scaled-up process module capable of depositing uniform films on batches of 4”or 6” diameter substrates in a production worthy operation was developed and qualified. In Phase III, the means to increase the throughput of the PVD-AlN system was evaluated and focused primarily on minimizing the impact of the substrate heating and cooling times that dominated the overall cycle time.

  20. Improved Poisson solver for cfa/magnetron simulation

    SciTech Connect

    Dombrowski, G.E.

    1996-12-31

    E{sub dc}, the static field of a device having vane-shaped anodes, has been determined by application of Hockney`s method, which in turn uses Buneman`s cyclic reduction. This result can be used for both cfa and magnetrons, but does not solve the general space-charge fields. As pointed out by Hockney, the matrix of coupling capacitive factors between the vane-defining mesh points can also be used to solve the Poisson equation for the entire cathode-anode domain. Space-charge fields of electrons between anode electrodes can now be determined. This technique also computes the Ramo function for the entire region. This method has been applied to the magnetron. Extension to the cfa with many different space-charge bunches does not appear to be practicable. Calculations for the type 4J50 magnetron by the various degrees of accuracy in solving the Poisson equation are compared with experimental measurements.

  1. Magnetron deposition of coatings with evaporation of the target

    NASA Astrophysics Data System (ADS)

    Bleykher, G. A.; Krivobokov, V. P.; Yuryeva, A. V.

    2015-12-01

    We analyze the potentialities of the plasma in various types of magnetron sputtering systems including pulsed and liquid-target systems for producing intense emission of atoms and high-rate deposition of coatings. For this purpose, a mathematical model of thermal and erosion processes in the target is developed based on the heat conduction equations taking into account first-order phase transitions. Using this model, we determine the parameters of magnetrons for which intense evaporation of atoms from the target surface takes place. It is shown that evaporation leads to an increase in the growth rate of metal coatings by 1-2 orders of magnitude as compared to conventional magnetron systems based only on collisional sputtering.

  2. Very low pressure high power impulse triggered magnetron sputtering

    SciTech Connect

    Anders, Andre; Andersson, Joakim

    2013-10-29

    A method and apparatus are described for very low pressure high powered magnetron sputtering of a coating onto a substrate. By the method of this invention, both substrate and coating target material are placed into an evacuable chamber, and the chamber pumped to vacuum. Thereafter a series of high impulse voltage pulses are applied to the target. Nearly simultaneously with each pulse, in one embodiment, a small cathodic arc source of the same material as the target is pulsed, triggering a plasma plume proximate to the surface of the target to thereby initiate the magnetron sputtering process. In another embodiment the plasma plume is generated using a pulsed laser aimed to strike an ablation target material positioned near the magnetron target surface.

  3. Magnetron Sputtered Gold Contacts on N-gaas

    NASA Technical Reports Server (NTRS)

    Buonaquisti, A. D.; Matson, R. J.; Russell, P. E.; Holloway, P. H.

    1984-01-01

    Direct current planar magnetron sputtering was used to deposit gold Schottky barrier electrical contacts on n-type GaAs of varying doping densities. The electrical character of the contact was determined from current voltage and electron beam induced voltage data. Without reducing the surface concentration of carbon and oxide, the contacts were found to be rectifying. There is evidence that energetic neutral particles reflected from the magnetron target strike the GaAs and cause interfacial damage similar to that observed for ion sputtering. Particle irradiation of the surface during contact deposition is discussed.

  4. Quantitative analysis of sputter processes in a small magnetron system

    SciTech Connect

    Knittel, Ivo; Gothe, Marc; Hartmann, Uwe

    2005-11-15

    Sputter deposition of titanium in argon from a small circular magnetron is characterized. The dependence of the deposition rate on pressure, power, and target-substrate distance has been measured. A framework for the application of the analytic approach by Keller and Simmons of ballistic and diffusive transport to simple three-dimensional sputter geometries is developed and applied. The sputter yield and the pressure-distance product are determined from the data set as the only fit parameters of the model. For the entire range of operation of the magnetron, the sputter process can be described in terms of the relatively simple approach.

  5. A high-efficiency relativistic magnetron with the filled dielectric

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Yu; Fan, Yu-Wei; Shi, Di-fu; Shu, Ting

    2016-07-01

    Relativistic magnetron (RM) is a popular high power microwave device. Filling the resonant cavities with the low-loss dielectric is a well-proven technology that improves the performance of RM. In order to enhance the power efficiency, a dielectric-filled relativistic magnetron (DFRM) is presented and investigated numerically with KARAT code in this paper. The simulation results indicate that the maximum power efficiency is enhanced from 50.0% in the conventional RM to 56.0% in the DFRM when the applied voltage and the magnetic field are 280 kV and 0.5 T, respectively. Besides, the simulation results are analyzed and discussed.

  6. Improved computer modelling of magnetron injection guns for gyrotrons

    SciTech Connect

    Caplan, M.; Thorington, C.

    1984-01-01

    A variable mesh finite-element electron gun design code has been developed to simulate hollow beams produced by magnetron injection guns. Very accurate solutions of the self-consistent space charge forces are obtained by using a computational mesh, distorted in a way which allows a high density of mesh points within the hollow beam. A generalized hybrid model for cathode emission has been incorporated which combines temperature limited and space charge limited emission in a way justified from empirical and physical arguments. Beam characteristics of a magnetron injection gun are presented as the transition from temperature limited to space charge limited operation is made. Limited comparisons with experimental results are presented.

  7. Magnetron sputtered boron films and Ti/B multilayer structures

    SciTech Connect

    Makowiecki, D.M.; Jankowski, A.F.

    1991-03-11

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor 5 deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity 10 from grazing to normal incidence.

  8. Magnetron sputtered boron films and Ti/B multilayer structures

    DOEpatents

    Makowiecki, D.M.; Jankowski, A.F.

    1995-02-14

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence. 6 figs.

  9. Magnetron sputtered boron films and TI/B multilayer structures

    DOEpatents

    Makowiecki, Daniel M.; Jankowski, Alan F.

    1993-01-01

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence.

  10. Magnetron sputtered boron films and Ti/B multilayer structures

    DOEpatents

    Makowiecki, Daniel M.; Jankowski, Alan F.

    1995-01-01

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence.

  11. Magnetron sputtered boron films and TI/B multilayer structures

    DOEpatents

    Makowiecki, D.M.; Jankowski, A.F.

    1993-04-20

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence.

  12. Analysis of the photo voltage decay /PVD/ method for measuring minority carrier lifetimes in P-N junction solar cells

    NASA Technical Reports Server (NTRS)

    Von Roos, O.

    1981-01-01

    The photo voltage decay (PVD) method for the measurement of minority carrier lifetimes in P-N junction solar cells with cell thickness comparable to or even less than the minority carrier diffusion length is examined. The method involves the generation of free carriers in the quasi-neutral bulk material by flashes of light and the monitoring of the subsequent decay of the induced open-circuit voltages as the carriers recombine, which is dependent on minority carrier recombination lifetime. It is shown that the voltage versus time curve for an ordinary solar cell (N(+)-P junction) is proportional to the inverse minority carrier lifetime plus a factor expressing the ratio of diffusion length to cell thickness. In the case of an ideal back-surface-field cell (N(+)-P-P(+) junction) however, the slope is directly proportional to the inverse minority carrier lifetime. It is noted that since most BSF cells are not ideal, possessing a sizable back surface recombination velocity, the PVD measurements must be treated with caution and supplemented with other nonstationary methods.

  13. Production of composite Si nanoparticles by plasma spraying PVD and CH4 annealing for negative electrodes of lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Ohta, Ryoshi; Ohta, Yutaro; Tashiro, Toru; Kambara, Makoto

    2015-09-01

    Si is a promising candidate as anode of next generation high density Li ion batteries. This material, however, needs to be nanostructured, nanoparticles and C coating of active material, to cope with huge volume change and associated rapid capacity decay. Si nanoparticles with 20-40 nm have been successfully produced by plasma spraying PVD and also Si-C core-shell composite particles by adding CH4 during processing. The battery performance has been improved with these nanopowders as anode, especially with the C coated Si particles. However, SiC that is inactive in battery reaction forms inevitably at high temperature during plasma spraying PVD and reduces the capacity density. In this work, therefore, post CH4 annealing was attempted to form Si-C nanocomposite particles while suppressing formation of SiC. The primary Si nanoparticles were unchanged in size after annealing and were coated with the finer carbonous particles that formed after CH4 infiltration through pores between nanoparticles. The batteries using annealed powders with C/Si molar ratio of 0.3 have shown two-fold capacity retention increase after 50 cycles with no capacity reduction associated with SiC formation as compared to the powders without C. This work was partly supported by the Funding Program for Next Generation World-Leading Researchers (NEXT Program) of Japan.

  14. Hemocompatibility of Inorganic Physical Vapor Deposition (PVD) Coatings on Thermoplastic Polyurethane Polymers

    PubMed Central

    Lackner, Juergen M.; Waldhauser, Wolfgang; Hartmann, Paul; Bruckert, Franz; Weidenhaupt, Marianne; Major, Roman; Sanak, Marek; Wiesinger, Martin; Heim, Daniel

    2012-01-01

    Biocompatibility improvements for blood contacting materials are of increasing interest for implanted devices and interventional tools. The current study focuses on inorganic (titanium, titanium nitride, titanium oxide) as well as diamond-like carbon (DLC) coating materials on polymer surfaces (thermoplastic polyurethane), deposited by magnetron sputtering und pulsed laser deposition at room temperature. DLC was used pure (a-C:H) as well as doped with silicon, titanium, and nitrogen + titanium (a-C:H:Si, a-C:H:Ti, a-C:H:N:Ti). In-vitro testing of the hemocompatibility requires mandatory dynamic test conditions to simulate in-vivo conditions, e.g., realized by a cone-and-plate analyzer. In such tests, titanium- and nitrogen-doped DLC and titanium nitride were found to be optimally anti-thrombotic and better than state-of-the-art polyurethane polymers. This is mainly due to the low tendency to platelet microparticle formation, a high content of remaining platelets in the whole blood after testing and low concentration of platelet activation and aggregation markers. Comparing this result to shear-flow induced cell motility tests with e.g., Dictostelium discoideum cell model organism reveals similar tendencies for the investigated materials. PMID:24955532

  15. Hemocompatibility of Inorganic Physical Vapor Deposition (PVD) Coatings on Thermoplastic Polyurethane Polymers.

    PubMed

    Lackner, Juergen M; Waldhauser, Wolfgang; Hartmann, Paul; Bruckert, Franz; Weidenhaupt, Marianne; Major, Roman; Sanak, Marek; Wiesinger, Martin; Heim, Daniel

    2012-01-01

    Biocompatibility improvements for blood contacting materials are of increasing interest for implanted devices and interventional tools. The current study focuses on inorganic (titanium, titanium nitride, titanium oxide) as well as diamond-like carbon (DLC) coating materials on polymer surfaces (thermoplastic polyurethane), deposited by magnetron sputtering und pulsed laser deposition at room temperature. DLC was used pure (a-C:H) as well as doped with silicon, titanium, and nitrogen + titanium (a-C:H:Si, a-C:H:Ti, a-C:H:N:Ti). In-vitro testing of the hemocompatibility requires mandatory dynamic test conditions to simulate in-vivo conditions, e.g., realized by a cone-and-plate analyzer. In such tests, titanium- and nitrogen-doped DLC and titanium nitride were found to be optimally anti-thrombotic and better than state-of-the-art polyurethane polymers. This is mainly due to the low tendency to platelet microparticle formation, a high content of remaining platelets in the whole blood after testing and low concentration of platelet activation and aggregation markers. Comparing this result to shear-flow induced cell motility tests with e.g., Dictostelium discoideum cell model organism reveals similar tendencies for the investigated materials. PMID:24955532

  16. Thermal conductivity of PVD TiAlN films using pulsed photothermal reflectance technique

    NASA Astrophysics Data System (ADS)

    Ding, Xing-Zhao; Samani, M. K.; Chen, George

    2010-11-01

    In the present work, we have measured thermal-conductivity of industrial thin film TiAlN with a thickness of around 3 μm. These films are used in machining industry for cutting tools in order to increase their service life. A series of TiAlN coating with a different Al/Ti atomic ratio were deposited on Fe-304 stainless steel (AISI304) substrate by a lateral rotating cathode arc process. The samples were then coated with a 0.8 μm gold layer on top by magnetron sputtering. We present the thermal-conductivity measurement of these samples using pulsed photothermal reflectance (PPR) technique at room temperature. The thermal conductivity of the pure TiN coating is about 11.9 W/mK. A significant decrease in thermal conductivity was found with increasing Al/Ti atomic ratio. A minimum thermal conductivity of about 4.63 W/mK was obtained at the Al/Ti atomic ratio of around 0.72.

  17. Geometrical Aspects of a Hollow-cathode Magnetron (HCM)

    SciTech Connect

    Cohen, Samuel, A.; Wang, Zhehui

    1998-11-01

    A hollow-cathode magnetron (HCM), built by surrounding a planar sputtering-magnetron cathode with a hollow-cathode structure (HCS), is operable at substantially lower pressures than its planar-magnetron counterpart. We have studied the dependence of magnetron operational parameters on the inner diameter D and length L of a cylindrical HCS. Only when L is greater than L sub zero, a critical length, is the HCM operable in the new low-pressure regime. The critical length varies with HCS inner diameter D. Explanations of the lower operational pressure regime, critical length, and plasma shape are proposed and compared with a one-dimension diffusion model for energetic or primary electron transport. At pressures above 1 mTorr, an electron-impact ionization model with Bohm diffusion at a temperature equivalent to one-half the primary electron energy and with an ambipolar constraint can explain the ion-electron pair creation required to sustain the discharge. The critical length L sub zero is determined by the magnetization length of the primary electrons.

  18. The target heating influence on the reactive magnetron sputtering process

    NASA Astrophysics Data System (ADS)

    Bondarenko, A.; Kolomiytsev, A.; Shapovalov, V.

    2016-07-01

    A physicochemical model for the reactive magnetron sputtering of a “hot” target is described in this paper. The system consisting of eight algebraic equations was solved for a tantalum target sputtered in an O2 environment. It was established that the hysteresis effect disappears with the increase of the ion current density.

  19. Contributions to the velocity spread of magnetron injection guns

    SciTech Connect

    Danly, B.G.; Kimura, T.; Kreischer, K.E.

    1995-12-31

    Various contributions to the velocity spread in magnetron injection guns for gyrotron applications have been studied, including the effects of misalignments, field errors, and cathode surface roughness. The net result of these effects is a substantial increase in spread over the ballistic spread usually calculated with typical gun codes.

  20. Extracytoplasmic Function (ECF) Sigma Factor Gene Regulation in Pseudomonas syringae: Integrated Molecular and Computational Characterization of PvdS-Regulated Promoters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The extracytoplasmic function (ECF) sigma factor PvdS regulates the expression of genes required for the biosynthesis and transport of pyoverdine, a siderophore that functions in iron acquisition. The production of pyoverdine is a distinctive trait of the fluorescent pseudomonads and the regulation ...

  1. Hysteresis behavior during reactive magnetron sputtering of Al{sub 2}O{sub 3} using a rotating cylindrical magnetron

    SciTech Connect

    Depla, D.; Haemers, J.; Buyle, G.; Gryse, R. de

    2006-07-15

    Rotating cylindrical magnetrons are used intensively on industrial scale. A rotating cylindrical magnetron on laboratory scale makes it possible to study this deposition technique in detail and under well controlled conditions. Therefore, a small scale rotating cylindrical magnetron was designed and used to study the influence of the rotation speed on the hysteresis behavior during reactive magnetron sputtering of aluminum in Ar/O{sub 2} in dc mode. This study reveals that the hysteresis shifts towards lower oxygen flows when the rotation speed of the target is increased, i.e., target poisoning occurs more readily when the rotation speed is increased. The shift is more pronounced for the lower branch of the hysteresis loop than for the upper branch of the hysteresis. This behavior can be understood qualitatively. The results also show that the oxidation mechanism inside the race track is different from the oxidation mechanism outside the race track. Indeed, outside the race track the oxidation mechanism is only defined by chemisorption while inside the race track reactive ion implantation will also influence the oxidation mechanism.

  2. Highly selective etching of silicon nitride to physical-vapor-deposited a-C mask in dual-frequency capacitively coupled CH{sub 2}F{sub 2}/H{sub 2} plasmas

    SciTech Connect

    Kim, J. S.; Kwon, B. S.; Heo, W.; Jung, C. R.; Park, J. S.; Shon, J. W.; Lee, N.-E.

    2010-01-15

    A multilevel resist (MLR) structure can be fabricated based on a very thin amorphous carbon (a-C) layer ( congruent with 80 nm) and Si{sub 3}N{sub 4} hard-mask layer ( congruent with 300 nm). The authors investigated the selective etching of the Si{sub 3}N{sub 4} layer using a physical-vapor-deposited (PVD) a-C mask in a dual-frequency superimposed capacitively coupled plasma etcher by varying the process parameters in the CH{sub 2}F{sub 2}/H{sub 2}/Ar plasmas, viz., the etch gas flow ratio, high-frequency source power (P{sub HF}), and low-frequency source power (P{sub LF}). They found that under certain etch conditions they obtain infinitely high etch selectivities of the Si{sub 3}N{sub 4} layers to the PVD a-C on both the blanket and patterned wafers. The etch gas flow ratio played a critical role in determining the process window for infinitely high Si{sub 3}N{sub 4}/PVD a-C etch selectivity because of the change in the degree of polymerization. The etch results of a patterned ArF photoresisit/bottom antireflective coating/SiO{sub x}/PVD a-C/Si{sub 3}N{sub 4} MLR structure supported the idea of using a very thin PVD a-C layer as an etch-mask layer for the Si{sub 3}N{sub 4} hard-mask pattern with a pattern width of congruent with 80 nm and high aspect ratio of congruent with 5.

  3. Low pressure hand made PVD system for high crystalline metal thin film preparation in micro-nanometer scale

    NASA Astrophysics Data System (ADS)

    Rosikhin, Ahmad; Hidayat, Aulia Fikri; Marimpul, Rinaldo; Syuhada, Ibnu; Winata, Toto

    2016-02-01

    High crystalline metal thin film preparation in application both for catalyst substrate or electrode in any electronic devices always to be considered in material functional material research and development. As a substrate catalyst, this metal take a role as guidance for material growth in order to resulted in proper surface structure although at the end it will be removed via etching process. Meanwhile as electrodes, it will dragging charges to be collected inside. This brief discussion will elaborate general fundamental principle of physical vapor deposition (PVD) system for metal thin film preparation in micro-nanometer scale. The influence of thermodynamic parameters and metal characteristic such as melting point and particle size will be elucidated. Physical description of deposition process in the chamber can be simplified by schematic evaporation phenomena which is supported by experimental measurement such as SEM and XRD.

  4. Microstructure evolution during annealing of TiAl/NiCoCrAl multilayer composite prepared by EB-PVD

    SciTech Connect

    Zhang, Rubing; Zhang, Deming; Chen, Guiqing; Wang, Yuesheng

    2014-07-01

    TiAl/NiCoCrAl laminate composite sheet with a thickness of 0.4–0.6 mm as well as a dimension of 150 mm × 100 mm was fabricated successfully by using electron beam physical vapor deposition (EB-PVD) method. The annealing treatment was processed at 1123 and 1323 K for 3 h in a high vacuum atmosphere, respectively. The phase composition and microstructure of TiAl/NiCoCrAl microlaminated sheet have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Based on the sheet characterization and results of the microstructure evolution during annealing treatment process, the diffusion mechanism of interfacial reaction in TiAl/NiCoCrAl microlaminate was investigated and discussed.

  5. Structural features and gas tightness of EB-PVD 1Ce10ScSZ electrolyte films

    NASA Astrophysics Data System (ADS)

    Andrzejczuk, M.; Vasylyev, O.; Brychevskyi, M.; Dubykivskyi, L.; Smirnova, A.; Lewandowska, M.; Kurzydłowski, K. J.; Steinberger-Wilckens, R.; Mertens, J.; Haanappel, V.

    2012-09-01

    The structure of Ceria doped Scandia Stabilized Zirconia (1Ce10ScSZ) electrolyte film deposited by EB-PVD (Electron Beam-Physical Vapour Deposition) technique on NiO-ZrO2 substrate was characterized by electron microscopy. The highly porous substrate was densely covered by deposited film without any spallation. The produced electrolyte layer was of a columnar structure with bushes, bundles of a diameter up to 30 μm and diverse height. Between the columns, delamination cracks of few microns length were visible. The annealing of zirconia film at 1000 °C resulted in its densification. The columnar grains and delaminating cracks changed their shape into a bit rounded. High magnification studies revealed nanopores 5-60 nm formed along the boundaries of the columnar grains during annealing. High-quality contacts between the electrolyte film and anode substrate ensured good conductivity of the electrolyte film and high efficiency of SOFC.

  6. Microwave Plasma Excitation Using Cylindrical Cavity with Dual Injection

    NASA Astrophysics Data System (ADS)

    Hasegawa, Yuichi; Nakamura, Keiji; Park, Soonam; Kobayashi, Satoru; Sugai, Hideo; Chubu University Team; Applied Materials Team; Nagoya Industrial Science Research Institute Team

    2015-09-01

    Large high-density plasmas have been generated by injecting magnetron-based microwaves radiated from slots cut on a wall of a rectangular or coaxial waveguide. However, a standing structural microwave in the waveguide often causes non-uniformity of plasma density. To minimize such inhomogeneity excited by the conventional waveguide, we adopt a resonant cylindrical cavity combined with a solid-state microwave amplifier. Microwave is injected into the cavity from two ports azimuthally apart by 90 degrees to each other (dual injection). FDTD simulations are performed for a TE111 mode resonant cavity excited by single or dual microwave injection. In the case of the dual injection with a phase difference of π/2, the wave field azimuthally rotates in the cavity, and hence the slots cut on a cavity bottom wall launch travelling waves, thus minimizing the azimuthal inhomogeneity of the resultant plasma. 40-cm-diameter plasmas are experimentally generated in argon at 0.1 ~ 5 Torr with microwaves of 2.4-2.5GHz and 400W. Threshold powers for plasma ignition are much less in dual injection than those in single injection. Optical emission images of the cylindrical plasmas show that the plasma uniformity is considerably improved in dual injection, particularly at high-pressure and low-power.

  7. Microwave beamed power technology improvement. [magnetrons and slotted waveguide arrays

    NASA Technical Reports Server (NTRS)

    Brown, W. C.

    1980-01-01

    The magnetron directional amplifier was tested for (1) phase shift and power output as a function of gain, anode current, and anode voltage, (2) background noise and harmonics in the output, (3) long life potential of the magnetron cathode, and (4) high operational efficiency. Examples of results were an adequate range of current and voltage over which 20 dB of amplification could be obtained, spectral noise density 155 dB below the carrier, 81.7% overall efficiency, and potential cathode life of 50 years in a design for solar power satellite use. A fabrication method was used to fabricate a 64 slot, 30 in square slotted waveguide array module from 0.020 in thick aluminum sheet. The test results on the array are discussed.

  8. Comprehensive computer model for magnetron sputtering. II. Charged particle transport

    SciTech Connect

    Jimenez, Francisco J. Dew, Steven K.; Field, David J.

    2014-11-01

    Discharges for magnetron sputter thin film deposition systems involve complex plasmas that are sensitively dependent on magnetic field configuration and strength, working gas species and pressure, chamber geometry, and discharge power. The authors present a numerical formulation for the general solution of these plasmas as a component of a comprehensive simulation capability for planar magnetron sputtering. This is an extensible, fully three-dimensional model supporting realistic magnetic fields and is self-consistently solvable on a desktop computer. The plasma model features a hybrid approach involving a Monte Carlo treatment of energetic electrons and ions, along with a coupled fluid model for thermalized particles. Validation against a well-known one-dimensional system is presented. Various strategies for improving numerical stability are investigated as is the sensitivity of the solution to various model and process parameters. In particular, the effect of magnetic field, argon gas pressure, and discharge power are studied.

  9. Linear ion source with magnetron hollow cathode discharge

    SciTech Connect

    Tang, D.L.; Pu, S.H.; Wang, L.S.; Qiu, X.M.; Chu, Paul K.

    2005-11-15

    A linear ion source with magnetron hollow cathode discharge is described in this paper. The linear ion source is based on an anode layer thruster with closed-drift electrons that move in a closed path in the ExB fields. An open slit configuration is designed at the end of the ion source for the extraction of the linear ion beam produced by the magnetron hollow cathode discharge. The special configurations enable uninterrupted and expanded operation with oxygen as well as other reactive gases because of the absence of an electron source in the ion source. The ion current density and uniformity were experimentally evaluated. Using the ion source, surface modification was conducted on polyethylene terephthalate polymer films to improve the adhesion strength with ZnS coatings.

  10. Equilibrium and Stability of the Brillouin Flow in Inverted Magnetron

    NASA Astrophysics Data System (ADS)

    Simon, David; Lau, Yue Ying; Franzi, Matt; Greening, Geoff; Gilgenbach, Ronald; Marhdahl, Peter; Hoff, Brad; Luginsland, John

    2012-10-01

    One embodiment of the novel recirculating planar magnetron, RPM [1] utilizes an inverted configuration for fast startup. While the negative mass behavior on the thin electron layer model [2] is well-known for the inverted magnetron, the corresponding behavior for the equilibrium Brillouin flow [3] is an open question. Simulations using the particle-in-cell codes ICEPIC and/or MAGIC will be performed and compared to the solution to the eigenvalue problem that governs the stability of Brillouin flow, leading to a fundamental study of the flow's negative, positive, and infinite mass properties. Research supported by AFOSR (grant#: FA9550-10-1-0104), AFRL, and L-3 Communications Electron Devices. [4pt] [1] R. M. Gilgenbach, et.al., IEEE Trans. Plasma Sci. 39, 980 (2011); Also patent pending.[0pt] [2] D. M. French, et al., Appl. Phys. Lett. 97, 111501 (2010).[0pt] [3] D. Simon, et al., Phys. Plasmas 19, 043103 (2012).

  11. Magnetron sputtering in rigid optical solar reflectors production

    NASA Astrophysics Data System (ADS)

    Asainov, O. Kh; Bainov, D. D.; Krivobokov, V. P.; Sidelev, D. V.

    2016-07-01

    Magnetron sputtering was applied to meet the growing need for glass optical solar reflectors. This plasma method provided more uniform deposition of the silver based coating on glass substrates resulted in decrease of defective reflectors fraction down to 5%. For instance, such parameter of resistive evaporation was of 30%. Silver film adhesion to glass substrate was enhanced with indium tin oxide sublayer. Sunlight absorption coefficient of these rigid reflectors was 0.081-0.083.

  12. Optical properties of magnetron-sputtered and rolled aluminum

    SciTech Connect

    Van Gils, S.; Dimogerontakis, Th.; Buytaert, G.; Stijns, E.; Terryn, H.; Skeldon, P.; Thompson, G.E.; Alexander, M.R.

    2005-10-15

    The optical properties of magnetron-sputtered aluminum and AA1050 aluminum alloy sheet have been examined qualitatively using total reflectance and quantitatively by means of visible spectroscopic ellipsometry (VISSE). Significant changes in reflectance and optical constants are observed, which are related to the incorporation of oxide in the aluminum bulk. The role of such oxide was determined by VISSE using the Bruggeman effective-medium approximation, with the findings validated by x-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy.

  13. Deposition of copper coatings in a magnetron with liquid target

    SciTech Connect

    Tumarkin, A. V. Kaziev, A. V.; Kolodko, D. V.; Pisarev, A. A.; Kharkov, M. M.; Khodachenko, G. V.

    2015-12-15

    Copper coatings were deposited on monocrystalline Si substrates using a magnetron discharge with a liquid cathode in the metal vapour plasma. During the deposition, the bias voltage in the range from 0 V to–400 V was applied to the substrate. The prepared films were investigated by a scanning electron microscope, and their adhesive properties were studied using a scratch tester. It was demonstrated that the adhesion of the deposited films strongly depends on the bias voltage and varies in a wide range.

  14. Magnetron co-sputtering system for coating ICF targets

    SciTech Connect

    Hsieh, E.J.; Meyer, S.F.; Halsey, W.G.; Jameson, G.T.; Wittmayer, F.J.

    1981-09-09

    Fabrication of Inertial Confinement Fusion (ICF) targets requires deposition of various types of coatings on microspheres. The mechanical strength, and surface finish of the coatings are of concern in ICF experiments. The tensile strength of coatings can be controlled through grain refinement, selective doping and alloy formation. We have constructed a magnetron co-sputtering system to produce variable density profile coatings with high tensile strength on microspheres.

  15. Calcium phosphate coatings produced by radiofrequency magnetron sputtering method

    NASA Astrophysics Data System (ADS)

    Bolbasov, E. N.; Zheravin, A. A.; Klimov, I. A.; Kulbakin, D. E.; Perelmuter, V. M.; Tverdokhlebov, S. I.; Cherdyntseva, N. V.; Choinzonov, E. L.

    2016-08-01

    Calcium phosphate coatings on titanium implants surface, produced by radio frequency (RF) magnetron sputtering method with hydroxyapatite solid target were investigated. It was found that produced coatings are calcium deficient compared to stoichiometric hydroxyapatite. The surface of the coatings is highly rough at the nanoscale and highly elastic. In vivo experiments on rats revealed that titanium implants with the calcium phosphate coatings do not cause negative tissue reaction after 6 months incubation period.

  16. Hollow target magnetron-sputter-type solid material ion source.

    PubMed

    Sasaki, D; Ieki, S; Kasuya, T; Wada, M

    2012-02-01

    A thin-walled aluminum (Al) hollow electrode has been inserted into an ion source to serve as an electrode for a radio frequency magnetron discharge. The produced plasma stabilized by argon (Ar) gas sputters the Al electrode to form a beam of Al(+) and Ar(+) ions. The total beam current extracted through a 3 mm diameter extraction hole has been 50 μA, with the Al(+) ion beam occupying 30% of the total beam current. PMID:22380320

  17. Theoretical investigation of the dielectric-filled relativistic magnetron

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoyu; Fan, Yuwei; Shu, Ting; Shi, Difu

    2016-01-01

    The fundamental mode frequency of a dielectric-filled relativistic magnetron is studied theoretically by the method of the equivalent circuit, and an exact fundamental mode frequency formula is derived. To prove the validity of the theoretical formula, simulation investigation is performed. The simulation results agree well with the theoretical formula, and the relative error does not exceed 3%. The comparative results verify the creditability of the theoretical formula.

  18. Hollow target magnetron-sputter-type solid material ion source

    SciTech Connect

    Sasaki, D.; Ieki, S.; Kasuya, T.; Wada, M.

    2012-02-15

    A thin-walled aluminum (Al) hollow electrode has been inserted into an ion source to serve as an electrode for a radio frequency magnetron discharge. The produced plasma stabilized by argon (Ar) gas sputters the Al electrode to form a beam of Al{sup +} and Ar{sup +} ions. The total beam current extracted through a 3 mm diameter extraction hole has been 50 {mu}A, with the Al{sup +} ion beam occupying 30% of the total beam current.

  19. Deposition of copper coatings in a magnetron with liquid target

    NASA Astrophysics Data System (ADS)

    Tumarkin, A. V.; Kaziev, A. V.; Kolodko, D. V.; Pisarev, A. A.; Kharkov, M. M.; Khodachenko, G. V.

    2015-12-01

    Copper coatings were deposited on monocrystalline Si substrates using a magnetron discharge with a liquid cathode in the metal vapour plasma. During the deposition, the bias voltage in the range from 0 V to-400 V was applied to the substrate. The prepared films were investigated by a scanning electron microscope, and their adhesive properties were studied using a scratch tester. It was demonstrated that the adhesion of the deposited films strongly depends on the bias voltage and varies in a wide range.

  20. High Peak Power Gyroklystron with an Inverted Magnetron Injection Gun

    NASA Astrophysics Data System (ADS)

    Read, Michael; Neilson, Jeff; Borchard, Philipp; Ives, Lawrence; Lawson, Wes

    2006-01-01

    This paper describes the design of a 25 MW, 30 GHz gyroklystron amplifier based on a coaxial RF structure. The design includes an inverted magnetron injection gun (MIG) for positioning and cooling the inner conductor. The gun produces a very low spread beam that contributes to a device efficiency of 54%. Details are given of the gun, RF structure, input and output couplers and collector.

  1. Passive mode control in the recirculating planar magnetron

    SciTech Connect

    Franzi, Matthew; Gilgenbach, Ronald; Lau, Y. Y.; Greening, Geoff; Zhang, Peng; Hoff, Brad

    2013-03-15

    Preliminary experiments of the recirculating planar magnetron microwave source have demonstrated that the device oscillates but is susceptible to intense mode competition due, in part, to poor coupling of RF fields between the two planar oscillators. A novel method of improving the cross-oscillator coupling has been simulated in the periodically slotted mode control cathode (MCC). The MCC, as opposed to a solid conductor, is designed to electromagnetically couple both planar oscillators by allowing for the propagation of RF fields and electrons through resonantly tuned gaps in the cathode. Using the MCC, a 12-cavity anode block with a simulated 1 GHz and 0.26 c phase velocity (where c is the speed of light) was able to achieve in-phase oscillations between the two sides of the device in as little as 30 ns. An analytic study of the modified resonant structure predicts the MCC's ability to direct the RF fields to provide tunable mode separation in the recirculating planar magnetron. The self-consistent solution is presented for both the degenerate even (in phase) and odd (180 Degree-Sign out of phase) modes that exist due to the twofold symmetry of the planar magnetrons.

  2. Passive mode control in the recirculating planar magnetron

    NASA Astrophysics Data System (ADS)

    Franzi, Matthew; Gilgenbach, Ronald; Lau, Y. Y.; Hoff, Brad; Greening, Geoff; Zhang, Peng

    2013-03-01

    Preliminary experiments of the recirculating planar magnetron microwave source have demonstrated that the device oscillates but is susceptible to intense mode competition due, in part, to poor coupling of RF fields between the two planar oscillators. A novel method of improving the cross-oscillator coupling has been simulated in the periodically slotted mode control cathode (MCC). The MCC, as opposed to a solid conductor, is designed to electromagnetically couple both planar oscillators by allowing for the propagation of RF fields and electrons through resonantly tuned gaps in the cathode. Using the MCC, a 12-cavity anode block with a simulated 1 GHz and 0.26 c phase velocity (where c is the speed of light) was able to achieve in-phase oscillations between the two sides of the device in as little as 30 ns. An analytic study of the modified resonant structure predicts the MCC's ability to direct the RF fields to provide tunable mode separation in the recirculating planar magnetron. The self-consistent solution is presented for both the degenerate even (in phase) and odd (180° out of phase) modes that exist due to the twofold symmetry of the planar magnetrons.

  3. Particle-in-Cell (PIC) simulation of CW industrial heating magnetron.

    PubMed

    Andreev, Andrey D; Hendricks, Kyle J

    2010-01-01

    Modern CW industrial heating magnetrons are capable for producing as high as 300 kW of continuous-wave microwave power at frequencies around 900 MHz and are sold commercially [Wynn et al., 2004]. However, to utilize these magnetrons in some specific research and scientific applications being of interest for the Air Force, the necessary adaptation and redesign are required. It means that the detailed knowledge of principles of their operation and full understanding of how the changes of the design parameters affect their operational characteristics are necessary. We have developed and tested computer model of a 10-vane high-power strapped magnetron, which geometrical dimensions and design parameters are close to those of the California Tube Laboratory's commercially produced CWM-75/100L tube. The computer model is built by using the 3-D Improved Concurrent Electromagnetic Particle-in-Cell (ICEPIC) code. Simulations of the strapped magnetron operation are performed and the following operational characteristics are obtained during the simulation: frequency and mode of magnetron oscillations, output microwave power and efficiency of magnetron operation, anode current and anode-cathode voltage dynamics. The developed computer model of a non-relativistic high-power strapped magnetron may be used by the industrial magnetron community for designing following generations of the CW industrial heating high-power magnetrons. PMID:21721323

  4. Influence of high power impulse magnetron sputtering plasma ionization on the microstructure of TiN thin films

    SciTech Connect

    Ehiasarian, A. P.; Vetushka, A.; Gonzalvo, Y. Aranda; Safran, G.; Szekely, L.; Barna, P. B.

    2011-05-15

    HIPIMS (High Power Impulse Magnetron Sputtering) discharge is a new PVD technology for the deposition of high-quality thin films. The deposition flux contains a high degree of metal ionization and nitrogen dissociation. The microstructure of HIPIMS-deposited nitride films is denser compared to conventional sputter technologies. However, the mechanisms acting on the microstructure, texture and properties have not been discussed in detail so far. In this study, the growth of TiN by HIPIMS of Ti in mixed Ar and N{sub 2} atmosphere has been investigated. Varying degrees of metal ionization and nitrogen dissociation were produced by increasing the peak discharge current (I{sub d}) from 5 to 30 A. The average power was maintained constant by adjusting the frequency. Mass spectrometry measurements of the deposition flux revealed a high content of ionized film-forming species, such as Ti{sup 1+}, Ti{sup 2+} and atomic nitrogen N{sup 1+}. Ti{sup 1+} ions with energies up to 50 eV were detected during the pulse with reducing energy in the pulse-off times. Langmuir probe measurements showed that the peak plasma density during the pulse was 3 x 10{sup 16} m{sup -3}. Plasma density, and ion flux ratios of N{sup 1+}: N{sub 2}{sup 1+} and Ti{sup 1+}: Ti{sup 0} increased linearly with peak current. The ratios exceeded 1 at 30 A. TiN films deposited by HIPIMS were analyzed by X-ray diffraction, and transmission electron microscopy. At high I{sub d}, N{sup 1+}: N{sub 2}{sup 1+} > 1 and Ti{sup 1+}: Ti{sup 0} > 1 were produced; a strong 002 texture was present and column boundaries in the films were atomically tight. As I{sub d} reduced and N{sup 1+}: N{sub 2}{sup 1+} and Ti{sup 1+}: Ti{sup 0} dropped below 1, the film texture switched to strong 111 with a dense structure. At very low I{sub d}, porosity between columns developed. The effects of the significant activation of the deposition flux observed in the HIPIMS discharge on the film texture, microstructure, morphology and

  5. Lithium ion conducting PVdF-HFP composite gel electrolytes based on N-methoxyethyl- N-methylpyrrolidinium bis(trifluoromethanesulfonyl)-imide ionic liquid

    NASA Astrophysics Data System (ADS)

    Ferrari, S.; Quartarone, E.; Mustarelli, P.; Magistris, A.; Fagnoni, M.; Protti, S.; Gerbaldi, C.; Spinella, A.

    Blends of PVdF-HFP and ionic liquids (ILs) are interesting for application as electrolytes in plastic Li batteries. They combine the advantages of the gel polymer electrolytes (GPEs) swollen by conventional organic liquid electrolytes with the nonflammability, and high thermal and electrochemical stability of ILs. In this work we prepared and characterized PVdF-HFP composite membranes swollen with a solution of LiTFSI in ether-functionalized pyrrolidinium-imide ionic liquid (PYRA 12O1TFSI). The membranes were filled in with two different types of silica: (i) mesoporous SiO 2 (SBA-15) and (ii) a commercial nano-size one (HiSil™ T700). The ionic conductivity and the electrochemical properties of the gel electrolytes were studied in terms of the nature of the filler. The thermal and the transport properties of the composite membranes are similar. In particular, room temperature ionic conductivities higher than 0.25 mS cm -1 are easily obtained at defined filler contents. However, the mesoporous filler guarantees higher lithium transference numbers, a more stable electrochemical interface and better cycling performances. Contrary to the HiSil™-based membrane, the Li/LiFePO 4 cells with PVdF-HFP/PYRA 12O1TFSI-LiTFSI films containing 10 wt% of SBA-15 show good charge/discharge capacity, columbic efficiency close to unity, and low capacity losses at medium C-rates during 180 cycles.

  6. [Standardized testing of bone implant surfaces with an osteoblast cell culture cyste. III. PVD hard coatings and Ti6Al4V].

    PubMed

    Steinert, A; Hendrich, C; Merklein, F; Rader, C P; Schütze, N; Thull, R; Eulert, J

    2000-12-01

    The effect of titanium-based PVD coatings and a titanium alloy on the proliferation and differentiation of osteoblasts was investigated using a standardised cell culture system. Human fetal osteoblasts (hFOB 1.19) were cultured on titanium-niobium-nitride ([Ti,Nb]N), titanium-niobium-oxy-nitride coatings ([Ti,Nb]ON) and titanium-aluminium-vanadium alloy (Ti6Al4V) for 17 days. Cell culture polystyrene (PS) was used as reference. For the assessment of proliferation, the numbers and viability of the cells were determined, while alkaline phosphatase activity, collagen I and osteocalcin synthesis served as differentiation parameters. On the basis of the cell culture experiments, a cytotoxic effect of the materials can be excluded. In comparison with the other test surfaces, [Ti,Nb]N showed greater cell proliferation. The [Ti,Nb]N coating was associated with the highest level of osteocalcin production, while all other differentiation parameters were identical on all three surfaces. The test system described reveals the influence of PVD coatings on the osteoblast differentiation cycle. The higher oxygen content of the [Ti,Nb]ON surface does not appear to have any positive impact on cell proliferation. The excellent biocompatibility of the PVD coatings is confirmed by in vivo findings. The possible use of these materials in the fields of osteosynthesis and articular surfaces is still under discussion. PMID:11194641

  7. Dual Wavelength Lasers

    NASA Technical Reports Server (NTRS)

    Walsh, Brian M.

    2010-01-01

    Dual wavelength lasers are discussed, covering fundamental aspects on the spectroscopy and laser dynamics of these systems. Results on Tm:Ho:Er:YAG dual wavelength laser action (Ho at 2.1 m and Er at 2.9 m) as well as Nd:YAG (1.06 and 1.3 m) are presented as examples of such dual wavelength systems. Dual wavelength lasers are not common, but there are criteria that govern their behavior. Based on experimental studies demonstrating simultaneous dual wavelength lasing, some general conclusions regarding the successful operation of multi-wavelength lasers can be made.

  8. Synthesizing mixed phase titania nanocomposites with enhanced photoactivity and redshifted photoresponse by reactive DC magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Chen, Le

    Recent work points out the importance of the solid-solid interface in explaining the high photoactivity of mixed phase TiO2 catalysts. The goal of this research was to probe the synthesis-structure-function relationships of the solid-solid interfaces created by the reactive direct current (DC) magnetron sputtering of titanium dioxide. I hypothesize that the reactive DC magnetron sputtering is a useful method for synthesizing photo-catalysts with unique structure including solid-solid interfaces and surface defects that are associated with enhanced photoreactivity as well as a photoresponse shifted to longer wavelengths of light. I showed that sputter deposition provides excellent control of the phase and interface formation as well as the stoichiometry of the films. I explored the effects exerted by the process parameters of pressure, oxygen partial pressure, target power, substrate bias (RF), deposition incidence angle, and post annealing treatment on the structural and functional characteristics of the catalysts. I have successfully made pure and mixed phase TiO2 films. These films were characterized with UV-Vis, XPS, AFM, SEM, TEM, XRD and EPR, to determine optical properties, elemental stoichiometry, surface morphology, phase distribution and chemical coordination. Bundles of anatase-rutile nano-columns having high densities of dual-scale of interfaces among and within the columns are fabricated. Photocatalytic performance of the sputtered films as measured by the oxidation of the pollutant, acetaldehyde, and the reduction of CO2 for fuel (CH4) production was compared (normalized for surface area) to that of mixed phase TiO2 fabricated by other methods, including flame hydrolysis powders, and solgel deposited TiO 2 films. The sputtered mixed phase materials were far superior to the commercial standard (Degussa P25) and solgel TiO2 based on gas phase reaction of acetaldehyde oxidation under UV light and CO2 reduction under both UV and visible illuminations. The

  9. Particle contamination formation and detection in magnetron sputtering processes

    SciTech Connect

    Selwyn, G.S.; Weiss, C.A.; Sequeda, F.; Huang, C.

    1996-10-01

    Defects caused by particulate contamination are an important concern in the fabrication of thin film products. Often, magnetron sputtering processes are used for this purpose. Particle contamination can cause electrical shorting, pin holes, problems with photolithography, adhesion failure, as well as visual and cosmetic defects. Particle contamination generated during thin film processing can be detected using laser light scattering, a powerful diagnostic technique that provides real-time, {ital in-situ} imaging of particles > 0.3 {mu}m in diameter. Using this technique, the causes, sources and influences on particles in plasma and non-plasma and non-plasma processes may be independently evaluated and corrected. Several studies employing laser light scattering have demonstrated both homogeneous and heterogeneous causes of particle contamination. In this paper, we demonstrate that the mechanisms for particle generation, transport and trapping during magnetron sputter deposition are different from the mechanisms reported in previously studied plasma etch processes. During magnetron sputter deposition, one source of particle contamination is linked to portions of the sputtering target surface exposed to weaker plasma density. In this region, film redeposition is followed by filament or nodule growth and enhanced trapping which increases filament growth. Eventually the filaments effectively ``short circuit`` the sheath, causing high currents to flow through these features. This, in turn, causes heating failure of the filament fracturing and ejecting the filaments into the plasma and onto the substrate. Evidence of this effect has been observed in semiconductor (IC) fabrication and storage disk manufacturing. Discovery of this mechanism in both technologies suggests that this mechanism may be universal to many sputtering processes.

  10. Plasma regimes in high power pulsed magnetron sputtering

    NASA Astrophysics Data System (ADS)

    de Los Arcos, Teresa

    2013-09-01

    High Power Pulsed Magnetron Sputtering (HPPMS) is a relatively recent variation of magnetron sputtering where high power is applied to the magnetron in short pulses. The result is the formation of dense transient plasmas with a high fraction of ionized species, ideally leading to better control of film growth through substrate bias. However, the broad range of experimental conditions accessible in pulsed discharges results in bewildering variations in current and voltage pulse shapes, pulse power densities, etc, which represent different discharge behaviors, making it difficult to identify relevant deposition conditions. The complexity of the plasma dynamics is evident. Within each pulse, plasma characteristics such as plasma composition, density, gas rarefaction, spatial distribution, degree of self-sputtering, etc. vary with time. A recent development has been the discovery that the plasma emission can self-organize into well-defined regions of high and low plasma emissivity above the racetrack (spokes), which rotate in the direction given by the E ×B drift and that significantly influence the transport mechanisms in HPPMS. One seemingly universal characteristic of HPPMS plasmas is the existence of well defined plasma regimes for different power ranges. These regimes are clearly differentiated in terms of plasma conductivity, plasma composition and spatial plasma self-organization. We will discuss the global characteristics of these regimes in terms of current-voltage characteristics, energy-resolved QMS and OES analysis, and fast imaging. In particular we will discuss how the reorganization of the plasma emission into spokes is associated only to specific regimes of high plasma conductivity. We will also briefly discuss the role of the target in shaping the characteristics of the HPPMS plasma, since sputtering is a surface-driven process. This work was supported by the Deutsche Forschungsgemeinschaft (DFG) within the framework of the SFB-TR87.

  11. PVD9902, a porcine vas deferens epithelial cell line that exhibits neurotransmitter-stimulated anion secretion and expresses numerous HCO3(-) transporters.

    PubMed

    Carlin, Ryan W; Sedlacek, Roger L; Quesnell, Rebecca R; Pierucci-Alves, Fernando; Grieger, David M; Schultz, Bruce D

    2006-06-01

    Epithelial ion transport disorders, including cystic fibrosis, adversely affect male reproductive function by nonobstructive mechanisms and by obstruction of the distal duct. Continuous cell lines that could be used to define ion transport mechanisms in this tissue are not readily available. In the present study, porcine vas deferens epithelial cells were isolated by standard techniques, and the cells spontaneously immortalized to form a porcine vas deferens epithelial cell line that we have titled PVD9902. Cells were maintained in continuous culture for >4 yr and 200 passages in a typical growth medium. Frozen stocks were generated, and thawed cells exhibited growth characteristics indistinguishable from their nonfrozen counterparts. Molecular and immunocytochemical studies confirmed the origin and epithelial nature of these cells. When seeded on permeable supports, PVD9902 cells grew as electrically tight (>6,000 ohms x cm2), confluent monolayers that responded to forskolin with an increase in short-circuit current (I(sc); 8 +/- 1 microA/cm2) that required Cl-, HCO3(-), and Na+, and was partially sensitive to bumetanide. mRNA was expressed for a number of anion transporters, including CFTR, electrogenic Na+-HCO3(-) cotransporter 1b (NBCe1b), downregulated in adenoma, pendrin, and Cl-/formate exchanger. Both forskolin and isoproterenol caused an increase in cellular cAMP levels. In addition, PVD9902 cell monolayers responded to physiological (i.e., adenosine, norepinephrine) and pharmacological [i.e., 5'-(N-ethylcarboxamido)adenosine, isoproterenol] agonists with increases in I(sc). Unlike their freshly isolated counterparts, however, PVD9902 cells did not respond to glucocorticoid exposure with an increase in amiloride-sensitive I(sc). RT-PCR analysis revealed the presence of both glucocorticoid and mineralocorticoid receptor mRNA as well as mRNA for the alpha- and gamma-subunits of the epithelia Na+ channels (alpha- and gamma-ENaC), but not beta

  12. The Magnetron Method for the Determination of e/m for Electrons: Revisited

    ERIC Educational Resources Information Center

    Azooz, A. A.

    2007-01-01

    Additional information concerning the energy distribution function of electrons in a magnetron diode valve can be extracted. This distribution function is a manifestation of the effect of space charge at the anode. The electron energy distribution function in the magnetron is obtained from studying the variation of the anode current with the…

  13. Magnetron co-sputtering system for coating ICF targets

    SciTech Connect

    Hsieh, E.J.; Meyer, S.F.; Halsey, W.G.; Jameson, G.T.; Wittmayer, F.J.

    1981-12-09

    Fabrication of Inertial Confinement Fusion (ICF) targets requires deposition of various types of coatings on microspheres. The mechanical strength, and surface finish of the coatings are of concern in ICF experiments. The tensile strength of coatings can be controlled through grain refinement, selective doping and alloy formation. We have constructed a magnetron co-sputtering system to produce variable density profile coatings with high tensile strength on microspheres. The preliminary data on the properties of a Au-Cu binary alloy system by SEM and STEM analysis is presented.

  14. Discharge current modes of high power impulse magnetron sputtering

    SciTech Connect

    Wu, Zhongzhen Xiao, Shu; Ma, Zhengyong; Cui, Suihan; Ji, Shunping; Pan, Feng; Tian, Xiubo; Fu, Ricky K. Y.; Chu, Paul K.

    2015-09-15

    Based on the production and disappearance of ions and electrons in the high power impulse magnetron sputtering plasma near the target, the expression of the discharge current is derived. Depending on the slope, six possible modes are deduced for the discharge current and the feasibility of each mode is discussed. The discharge parameters and target properties are simplified into the discharge voltage, sputtering yield, and ionization energy which mainly affect the discharge plasma. The relationship between these factors and the discharge current modes is also investigated.

  15. Liner conformality in ionized magnetron sputter metal deposition processes

    SciTech Connect

    Hamaguchi, S.; Rossnagel, S.M.

    1996-07-01

    The conformality of thin metal films (liners) formed on high-aspect-ratio trench structures in ionized magnetron sputter deposition processes is studied numerically and experimentally. The numerical simulator (SHADE) used to predict the surface topography is based on the shock-tracking method for surface evolution. The simulation results are in good agreement with experimentally observed thin-film topography. It is shown that combination of direct deposition and trench-bottom resputtering results in good conformality of step coverages and the amount of the resputtering needed for the good conformality is almost independent of trench aspect ratios. {copyright} {ital 1996 American Vacuum Society}

  16. Lateral variation of target poisoning during reactive magnetron sputtering

    SciTech Connect

    Guettler, D.; Groetzschel, R.; Moeller, W.

    2007-06-25

    The reactive gas incorporation into a Ti sputter target has been investigated using laterally resolving ion beam analysis during dc magnetron deposition of TiN in an Ar/N{sub 2} atmosphere. At sufficiently low reactive gas flow, the nitrogen incorporation exhibits a pronounced lateral variation, with a lower areal density in the target racetrack compared to the target center and edge. The findings are reproduced by model calculations. In the racetrack, the balance of reactive gas injection and sputter erosion is shifted toward erosion. The injection of nitrogen is dominated by combined molecular adsorption and recoil implantation versus direct ion implantation.

  17. Simulation of the velocity spread in magnetron injection guns

    SciTech Connect

    Liu, C.; Antonsen, T.M. Jr.; Levush, B.

    1996-06-01

    The velocity spread associated with phase mixing due to dc space charge in a magnetron injection gun (MIG) is investigated. A simple model is introduced to describe the mixing process. Simulations are performed by using the results of the EGUN trajectory calculation for initial conditions at the entrance of the drift region. Results for a 170 GHz gun are obtained and compared with EGUN simulations. This new model provides a more accurate and efficient approach for analyzing the velocity spread due to mixing in MIG`s.

  18. Heteroepitaxial Ge-on-Si by DC magnetron sputtering

    SciTech Connect

    Steglich, Martin; Schrempel, Frank; Füchsel, Kevin; Kley, Ernst-Bernhard; Patzig, Christian; Berthold, Lutz; Höche, Thomas; Tünnermann, Andreas

    2013-07-15

    The growth of Ge on Si(100) by DC Magnetron Sputtering at various temperatures is studied by Spectroscopic Ellipsometry and Transmission Electron Microscopy. Smooth heteroepitaxial Ge films are prepared at relatively low temperatures of 380°C. Typical Stransky-Krastanov growth is observed at 410°C. At lower temperatures (320°C), films are essentially amorphous with isolated nanocrystallites at the Si-Ge interface. A minor oxygen contamination at the interface, developing after ex-situ oxide removal, is not seen to hinder epitaxy. Compensation of dislocation-induced acceptors in Ge by sputtering from n-doped targets is proposed.

  19. Characterization and optimization of the magnetron directional amplifier

    NASA Astrophysics Data System (ADS)

    Hatfield, Michael Craig

    Many applications of microwave wireless power transmission (WPT) are dependent upon a high-powered electronically-steerable phased array composed of many radiating modules. The phase output from the high-gain amplifier in each module must be accurately controlled if the beam is to be properly steered. A highly reliable, rugged, and inexpensive design is essential for making WPT applications practical. A conventional microwave oven magnetron may be combined with a ferrite circulator and other external circuitry to create such a system. By converting it into a two-port amplifier, the magnetron is capable of delivering at least 30 dB of power gain while remaining phase-locked to the input signal over a wide frequency range. The use of the magnetron in this manner is referred to as a MDA (Magnetron Directional Amplifier). The MDA may be integrated with an inexpensive slotted waveguide array (SWA) antenna to form the Electronically-Steerable Phased Array Module (ESPAM). The ESPAM provides a building block approach to creating phased arrays for WPT. The size and shape of the phased array may be tailored to satisfy a diverse range of applications. This study provided an in depth examination into the capabilities of the MDA/ESPAM. The basic behavior of the MDA was already understood, as well as its potential applicability to WPT. The primary objective of this effort was to quantify how well the MDA could perform in this capacity. Subordinate tasks included characterizing the MDA behavior in terms of its system inputs, optimizing its performance, performing sensitivity analyses, and identifying operating limitations. A secondary portion of this study examined the suitability of the ESPAM in satisfying system requirements for the solar power satellite (SPS). Supporting tasks included an analysis of SPS requirements, modeling of the SWA antenna, and the demonstration of a simplified phased array constructed of ESPAM elements. The MDA/ESPAM is well suited for use as an

  20. Lateral variation of target poisoning during reactive magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Güttler, D.; Grötzschel, R.; Möller, W.

    2007-06-01

    The reactive gas incorporation into a Ti sputter target has been investigated using laterally resolving ion beam analysis during dc magnetron deposition of TiN in an Ar /N2 atmosphere. At sufficiently low reactive gas flow, the nitrogen incorporation exhibits a pronounced lateral variation, with a lower areal density in the target racetrack compared to the target center and edge. The findings are reproduced by model calculations. In the racetrack, the balance of reactive gas injection and sputter erosion is shifted toward erosion. The injection of nitrogen is dominated by combined molecular adsorption and recoil implantation versus direct ion implantation.

  1. Characterization of Magnetron Sputtered Coatings by Pulsed Eddy Current Techniques

    SciTech Connect

    Mulligan, Chris; Lee Changqing; Danon, Yaron

    2005-04-09

    A method that uses induced pulsed eddy currents for characterization of thick magnetron sputtered Nb coatings on steel is presented in this paper. The objectives of this work are to develop a system for rapid quantitative nondestructive inspection of coatings as well as to determine the correlation between coating properties, such as density and purity, and eddy current measured resistivity of coatings. A two-probe differential system having higher sensitivity and less noise than a one-probe system with 2-D scanning ability was developed.

  2. First demonstration and performance of an injection locked continuous wave magnetron to phase control a superconducting cavity

    SciTech Connect

    A.C. Dexter, G. Burt, R.G. Carter, I. Tahir, H. Wang, K. Davis, R. Rimmer

    2011-03-01

    The applications of magnetrons to high power proton and cw electron linacs are discussed. An experiment is described where a 2.45 GHz magnetron has been used to drive a single cell superconducting cavity. With the magnetron injection locked, a modest phase control accuracy of 0.95° rms has been demonstrated. Factors limiting performance have been identified.

  3. Modulated electron cyclotron drift instability in a high-power pulsed magnetron discharge.

    PubMed

    Tsikata, Sedina; Minea, Tiberiu

    2015-05-01

    The electron cyclotron drift instability, implicated in electron heating and anomalous transport, is detected in the plasma of a planar magnetron. Electron density fluctuations associated with the mode are identified via an adapted coherent Thomson scattering diagnostic, under direct current and high-power pulsed magnetron operation. Time-resolved analysis of the mode amplitude reveals that the instability, found at MHz frequencies and millimeter scales, also exhibits a kHz-scale modulation consistent with the observation of larger-scale plasma density nonuniformities, such as the rotating spoke. Sharply collimated axial fluctuations observed at the magnetron axis are consistent with the presence of escaping electrons in a region where the magnetic and electric fields are antiparallel. These results distinguish aspects of magnetron physics from other plasma sources of similar geometry, such as the Hall thruster, and broaden the scope of instabilities which may be considered to dictate magnetron plasma features. PMID:26001007

  4. Modulated Electron Cyclotron Drift Instability in a High-Power Pulsed Magnetron Discharge

    NASA Astrophysics Data System (ADS)

    Tsikata, Sedina; Minea, Tiberiu

    2015-05-01

    The electron cyclotron drift instability, implicated in electron heating and anomalous transport, is detected in the plasma of a planar magnetron. Electron density fluctuations associated with the mode are identified via an adapted coherent Thomson scattering diagnostic, under direct current and high-power pulsed magnetron operation. Time-resolved analysis of the mode amplitude reveals that the instability, found at MHz frequencies and millimeter scales, also exhibits a kHz-scale modulation consistent with the observation of larger-scale plasma density nonuniformities, such as the rotating spoke. Sharply collimated axial fluctuations observed at the magnetron axis are consistent with the presence of escaping electrons in a region where the magnetic and electric fields are antiparallel. These results distinguish aspects of magnetron physics from other plasma sources of similar geometry, such as the Hall thruster, and broaden the scope of instabilities which may be considered to dictate magnetron plasma features.

  5. Closed field unbalanced magnetron sputtering ion plating of Ni/Al thin films: influence of the magnetron power.

    PubMed

    Said, R; Ahmed, W; Gracio, J

    2010-04-01

    In this study NiAl thin films have been deposited using closed field unbalanced magnetron sputtering Ion plating (CFUBMSIP). The influence of magnetron power has been investigated using dense and humongous NiAl compound targets onto stainless steel and glass substrates. Potential applications include tribological, electronic media and bond coatings in thermal barrier coatings system. Several techniques has been used to characterise the films including surface stylus profilometry, energy dispersive spectroscopy (EDAX), X-Ray diffraction (XRD) Composition analysis of the samples was carried out using VGTOF SIMS (IX23LS) and Atomic force microscopy (AFM). Scratch tester (CSM) combined with acoustic emission singles during loading in order to compare the coating adhesion. The acoustic emission signals emitted during the indentation process were used to determine the critical load, under which the film begins to crack and/or break off the substrate. The average thickness of the films was approximately 1 um. EDAX results of NiAl thin films coating with various magnetron power exhibited the near equal atomic% Ni:Al. The best result being obtained using 300 W and 400 W DC power for Ni and Al targets respectively. XRD revealed the presence of beta NiAl phase for all the films coatings. AFM analysis of the films deposited on glass substrates exhibited quite a smooth surface with surface roughness values in the nanometre range. CSM results indicate that best adhesion was achieved at 300 W for Ni, and 400 W for Al targets compared to sample other power values. SIMS depth profile showed a uniform distribution of the Ni and Al component from the surface of the film to the interface. PMID:20355462

  6. Plasma potential mapping of high power impulse magnetron sputtering discharges

    SciTech Connect

    Rauch, Albert; Mendelsberg, Rueben J.; Sanders, Jason M.; Anders, Andre

    2011-12-20

    Pulsed emissive probe techniques have been used to determine the plasma potential distribution of high power impulse magnetron sputtering (HiPIMS) discharges. An unbalanced magnetron with a niobium target in argon was investigated for pulse length of 100 μs at a pulse repetition rate of 100 Hz, giving a peak current of 170 A. The probe data were taken with a time resolution of 20 ns and a spatial resolution of 1 mm. It is shown that the local plasma potential varies greatly in space and time. The lowest potential was found over the target’s racetrack, gradually reaching anode potential (ground) several centimeters away from the target. The magnetic pre-sheath exhibits a funnel-shaped plasma potential resulting in an electric field which accelerates ions toward the racetrack. In certain regions and times, the potential exhibits weak local maxima which allow for ion acceleration to the substrate. Knowledge of the local E and static B fields lets us derive the electrons’ E×B drift velocity, which is about 105 m/s and shows structures in space and time.

  7. Electrical characterization of an rf planar magnetron in inert gases

    NASA Astrophysics Data System (ADS)

    Minea, T. M.; Bretagne, J.; Pagnon, D.; Touzeau, M.

    2000-08-01

    Electrical aspects of an rf planar magnetron discharge in noble gases at pressures below 50 mTorr are discussed. The electrical parameters of the experimental device are measured by a diagnostic system consisting of two probes, a capacitive voltage divider and a current loop. The measurements of the rf current and voltage and the fast Fourier transform treatment of recorded signals are used to verify the validity of the `subtraction' method in order to estimate the power deposited into the plasma. This technique shows a better power coupling with a metallic target, up to 90% of the rf delivered power, than for an insulating target for which the power efficiency hardly reaches 50%. In addition, the elementary mechanisms sustaining the rf planar magnetron discharge are analysed. A transition from a combination of α (`wave-riding') and γ (secondary electron emission) regimes above a critical pressure to an α dominant regime at very low pressure is pointed out. This phenomenon is explained by the results of a particle-in-cell Monte Carlo collision simulation.

  8. On Tomonaga's theory of split-anode magnetrons

    NASA Astrophysics Data System (ADS)

    Dittrich, Walter

    2016-06-01

    This article offers a review of the history of radar research and its application in the 20th century. After describing the wartime work of Sin-Itiro Tomonaga and his theory of the cavity magnetron, we formulate the equations of motion of an electron in a cavity magnetron using action-angle variables. This means following the electron's path on its way from a cylindrical cathode moving toward a co-axial cylindrical anode in presence of a uniform magnetic field parallel to the common axis. After analyzing the situation without coupling to an external oscillatory electric field, we employ methods of canonical perturbation theory to find the resonance condition between the frequencies of the free theory ωr, ωϕ and the applied perturbing oscillatory frequency ω. A long-time averaging process will then eliminate the periodic terms in the equation for the now time-dependent action-angle variables. The terms that are no longer periodic will cause secular changes so that the canonical action-angle variables (J, δ) change in a way that the path of the electron will deform gradually so that it can reach the anode. How the ensemble of the initially randomly distributed electrons forms spokes and how their energy is conveyed to the cavity-field oscillation is the main focus of this article. Some remarks concerning the importance of results in QED and the invention of radar theory and application conclude the article.

  9. Double circular erosion patterns on dielectric target in magnetron sputtering.

    PubMed

    Suzaki, Yoshifumi; Miyagawa, Hayato; Ejima, Seiki

    2009-10-01

    In rf magnetron sputtering, a circular erosion pattern forms on the surface of a circular metal conductor target with permanent magnets on its back. In this case, the theory behind the erosion pattern has been established. However, in the case of a dielectric target, a double circular erosion pattern is formed. So far, this pattern has been phenomenologically recognized by experimenters; however, it has not yet been investigated. In this study, we performed a magnetron sputtering experiment with a SiO2 dielectric target, and confirmed the formation of a double circular erosion pattern. The dimensions of the double circular erosion pattern varied depending on the insulation resistance or the thickness of the SiO2 target. Furthermore, we found that the dimensions of a double circular erosion pattern changed by making a gap between the SiO2 target and guard ring. Based on the experimental results, we have proposed a qualitative model to explain the formation mechanism of double circular erosion patterns. PMID:19895082

  10. On Tomonaga's theory of split-anode magnetrons

    NASA Astrophysics Data System (ADS)

    Dittrich, Walter

    2016-05-01

    This article offers a review of the history of radar research and its application in the 20th century. After describing the wartime work of Sin-Itiro Tomonaga and his theory of the cavity magnetron, we formulate the equations of motion of an electron in a cavity magnetron using action-angle variables. This means following the electron's path on its way from a cylindrical cathode moving toward a co-axial cylindrical anode in presence of a uniform magnetic field parallel to the common axis. After analyzing the situation without coupling to an external oscillatory electric field, we employ methods of canonical perturbation theory to find the resonance condition between the frequencies of the free theory ω r ,ω ϕ and the applied perturbing oscillatory frequency ω. A long-time averaging process will then eliminate the periodic terms in the equation for the now time-dependent action-angle variables. The terms that are no longer periodic will cause secular changes so that the canonical action-angle variables (J,δ) change in a way that the path of the electron will deform gradually so that it can reach the anode. How the ensemble of the initially randomly distributed electrons forms spokes and how their energy is conveyed to the cavity-field oscillation is the main focus of this article. Some remarks concerning the importance of results in QED and the invention of radar theory and application conclude the article.

  11. Magnetron Driven L Band RF Gun using a Photocathode Emitter

    NASA Astrophysics Data System (ADS)

    Evans, Kirk; Fisher, Amnon; Friedman, Moshe

    1996-11-01

    Magnetron Driven L Band RF Gun using a Photocathode Emitter A tunable 5 megawatt L-Band injection locked magnetron amplifier is used to drive a 1-1/2 cell RF cavity gun, to produce a 2.5 megavolt electron beam. A tunable RF source relaxes the precision of the cavity gun construction, and therefore simplifies the design and reduces the overall cost. The design of the L-Band ( 1.3 GHz) RF cavity linear accelerator is presented, along with Superfish, SOS computer simulations, and calculations of beam energy and temporal qualities. Measurements of a few robust photocathode materials as well as measurements of the beam qualities of the final accelerator are presented. Future work will utilize new semiconductor laser diodes that can be electrically driven in the gigahertz range. This makes possible an electron gun system which can run at the RF frequency used to accelerate the electron beam. Such a system produces a "lock to clock" and synchronized RF and electron beam source which can be run single shot or any rep rate up to the RF frequency.

  12. Plasma potential mapping of high power impulse magnetron sputtering discharges

    SciTech Connect

    Rauch, Albert; Mendelsberg, Rueben J.; Sanders, Jason M.; Anders, Andre

    2012-04-15

    Pulsed emissive probe techniques have been used to determine the plasma potential distribution of high power impulse magnetron sputtering (HiPIMS) discharges. An unbalanced magnetron with a niobium target in argon was investigated for a pulse length of 100 {mu}s at a pulse repetition rate of 100 Hz, giving a peak current of 170 A. The probe data were recorded with a time resolution of 20 ns and a spatial resolution of 1 mm. It is shown that the local plasma potential varies greatly in space and time. The lowest potential was found over the target's racetrack, gradually reaching anode potential (ground) several centimeters away from the target. The magnetic presheath exhibits a funnel-shaped plasma potential resulting in an electric field which accelerates ions toward the racetrack. In certain regions and times, the potential exhibits weak local maxima which allow for ion acceleration to the substrate. Knowledge of the local E and static B fields lets us derive the electrons'ExB drift velocity, which is about 10{sup 5} m/s and shows structures in space and time.

  13. Asymmetric particle fluxes from drifting ionization zones in sputtering magnetrons

    NASA Astrophysics Data System (ADS)

    Panjan, Matjaž; Franz, Robert; Anders, André

    2014-04-01

    Electron and ion fluxes from direct current and high-power impulse magnetron sputtering (dcMS and HiPIMS) plasmas were measured in the plane of the target surface. Biased collector probes and a particle energy and mass analyzer showed asymmetric emission of electrons and of singly and doubly charged ions. For both HiPIMS and dcMS discharges, higher fluxes of all types of particles were observed in the direction of the electrons' E × B drift. These results are put in the context with ionization zones that drift over the magnetron's racetrack. The measured currents of time-resolving collector probes suggest that a large fraction of the ion flux originates from drifting ionization zones, while energy-resolving mass spectrometry indicates that a large fraction of the ion energy is due to acceleration by an electric field. This supports the recently proposed hypothesis that each ionization zone is associated with a negative-positive-negative space charge structure, thereby producing an electric field that accelerates ions from the location where they were formed.

  14. EMI shielding using composite materials with two sources magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Ziaja, J.; Jaroszewski, M.; Lewandowski, M.

    2016-02-01

    In this study, the preparation composite materials for electromagnetic shields using two sources magnetron sputtering DC-M is presented. A composite material was prepared by coating a nonwoven polypropylene metallic layer in sputtering process of targets Ti (purity 99%) and brass alloy MO58 (58%Cu, 40%Zn, 2%Pb) and ϕ diameter targets = 50 mm, under argon atmosphere. The system with magnetron sputtering sources was powered using switch-mode power supply DPS (Dora Power System) with a maximum power of 16 kW and a maximum voltage of 1.2 kV with group frequency from 50 Hz to 5 kHz. The influence of sputtering time of individual targets on the value of the EM field attenuation SE [dB] was investigated for the following supply conditions: pressure pp = 2x10-3 Torr, sputtering power P = 750 W, the time of applying a layer t = 5 min, group frequency fg = 2 kHz, the frequency of switching between targets fp = 1 Hz.

  15. Unbalance magnetron plasma source for ion mass-separator

    NASA Astrophysics Data System (ADS)

    Paperny, V. L.; Krasov, V. I.; Astrakchantsev, N. V.; Lebedev, N. V.

    2014-11-01

    The report presents the results of the preliminary studies characteristics of an unbalanced magnetron plasma source supplied with the transport system based on a curved magnetic field. The aim of these studies was to recognize if the system is suitable, in principle, for mass-separation of a multi-component plasma flow. The magnetron source has 50 mm diameter cathode manufactured of an alloy composed of Cu (64%), Pb (22.5%) and admixtures, about of 14% (Al, Zn, C). By means of an immersion time-of-flight spectrometer, a spatial distribution of ions of the cathode material was measured through the system output cross-section. Distribution of atom of these elements was measured here by the X-ray fluorescence spectrometry as well. Both methods showed that the ions of the lighter element (Cu) were concentrated in the inner part of the plasma flow deflected by the magnetic field while the distribution of the heavy element (Pb) was shifted toward the outer area of the flow. The similar effect was observed for each couple of the elements. Such a system is promising for use in plasma technology of reprocessing spent nuclear fuel, namely for separation heavy radioactive fission product from nuclear waste.

  16. Elementary surface processes during reactive magnetron sputtering of chromium

    SciTech Connect

    Monje, Sascha; Corbella, Carles Keudell, Achim von

    2015-10-07

    The elementary surface processes occurring on chromium targets exposed to reactive plasmas have been mimicked in beam experiments by using quantified fluxes of Ar ions (400–800 eV) and oxygen atoms and molecules. For this, quartz crystal microbalances were previously coated with Cr thin films by means of high-power pulsed magnetron sputtering. The measured growth and etching rates were fitted by flux balance equations, which provided sputter yields of around 0.05 for the compound phase and a sticking coefficient of O{sub 2} of 0.38 on the bare Cr surface. Further fitted parameters were the oxygen implantation efficiency and the density of oxidation sites at the surface. The increase in site density with a factor 4 at early phases of reactive sputtering is identified as a relevant mechanism of Cr oxidation. This ion-enhanced oxygen uptake can be attributed to Cr surface roughening and knock-on implantation of oxygen atoms deeper into the target. This work, besides providing fundamental data to control oxidation state of Cr targets, shows that the extended Berg's model constitutes a robust set of rate equations suitable to describe reactive magnetron sputtering of metals.

  17. An inverted cylindrical sputter magnetron as metal vapor supply for electron cyclotron resonance ion sources

    SciTech Connect

    Weichsel, T. Hartung, U.; Kopte, T.; Zschornack, G.; Kreller, M.; Silze, A.

    2014-05-15

    An inverted cylindrical sputter magnetron device has been developed. The magnetron is acting as a metal vapor supply for an electron cyclotron resonance (ECR) ion source. FEM simulation of magnetic flux density was used to ensure that there is no critical interaction between both magnetic fields of magnetron and ECR ion source. Spatially resolved double Langmuir probe and optical emission spectroscopy measurements show an increase in electron density by one order of magnitude from 1 × 10{sup 10} cm{sup −3} to 1 × 10{sup 11} cm{sup −3}, when the magnetron plasma is exposed to the magnetic mirror field of the ECR ion source. Electron density enhancement is also indicated by magnetron plasma emission photography with a CCD camera. Furthermore, photographs visualize the formation of a localized loss-cone - area, when the magnetron is operated at magnetic mirror field conditions. The inverted cylindrical magnetron supplies a metal atom load rate of R > 1 × 10{sup 18} atoms/s for aluminum, which meets the demand for the production of a milliampere Al{sup +} ion beam.

  18. An inverted cylindrical sputter magnetron as metal vapor supply for electron cyclotron resonance ion sources.

    PubMed

    Weichsel, T; Hartung, U; Kopte, T; Zschornack, G; Kreller, M; Silze, A

    2014-05-01

    An inverted cylindrical sputter magnetron device has been developed. The magnetron is acting as a metal vapor supply for an electron cyclotron resonance (ECR) ion source. FEM simulation of magnetic flux density was used to ensure that there is no critical interaction between both magnetic fields of magnetron and ECR ion source. Spatially resolved double Langmuir probe and optical emission spectroscopy measurements show an increase in electron density by one order of magnitude from 1 × 10(10) cm(-3) to 1 × 10(11) cm(-3), when the magnetron plasma is exposed to the magnetic mirror field of the ECR ion source. Electron density enhancement is also indicated by magnetron plasma emission photography with a CCD camera. Furthermore, photographs visualize the formation of a localized loss-cone - area, when the magnetron is operated at magnetic mirror field conditions. The inverted cylindrical magnetron supplies a metal atom load rate of R > 1 × 10(18) atoms/s for aluminum, which meets the demand for the production of a milliampere Al(+) ion beam. PMID:24880358

  19. Derivation and generalization of the dispersion relation of rising-sun magnetron with sectorial and rectangular cavities

    SciTech Connect

    Shi, Di-Fu; Qian, Bao-Liang; Wang, Hong-Gang; Li, Wei

    2013-12-15

    Field analysis method is used to derive the dispersion relation of rising-sun magnetron with sectorial and rectangular cavities. This dispersion relation is then extended to the general case in which the rising-sun magnetron can be with multi-group cavities of different shapes and sizes, and from which the dispersion relations of conventional magnetron, rising-sun magnetron, and magnetron-like device can be obtained directly. The results show that the relative errors between the theoretical and simulation values of the dispersion relation are less than 3%, the relative errors between the theoretical and simulation values of the cutoff frequencies of π mode are less than 2%. In addition, the influences of each structure parameter of the magnetron on the cutoff frequency of π mode and on the mode separation are investigated qualitatively and quantitatively, which may be of great interest to designing a frequency tuning magnetron.

  20. Advanced process control and novel test methods for PVD silicon and elastomeric silicone coatings utilized on ion implant disks, heatsinks and selected platens

    SciTech Connect

    Springer, J.; Allen, B.; Wriggins, W.; Kuzbyt, R.; Sinclair, R.

    2012-11-06

    Coatings play multiple key roles in the proper functioning of mature and current ion implanters. Batch and serial implanters require strategic control of elemental and particulate contamination which often includes scrutiny of the silicon surface coatings encountering direct beam contact. Elastomeric Silicone Coatings must accommodate wafer loading and unloading as well as direct backside contact during implant plus must maintain rigid elemental and particulate specifications. The semiconductor industry has had a significant and continuous effort to obtain ultra-pure silicon coatings with sustained process performance and long life. Low particles and reduced elemental levels for silicon coatings are a major requirement for process engineers, OEM manufacturers, and second source suppliers. Relevant data will be presented. Some emphasis and detail will be placed on the structure and characteristics of a relatively new PVD Silicon Coating process that is very dense and homogeneous. Wear rate under typical ion beam test conditions will be discussed. The PVD Silicon Coating that will be presented here is used on disk shields, wafer handling fingers/fences, exclusion zones of heat sinks, beam dumps and other beamline components. Older, legacy implanters can now provide extended process capability using this new generation PVD silicon - even on implanter systems that were shipped long before the advent of silicon coating for contamination control. Low particles and reduced elemental levels are critical performance criteria for the silicone elastomers used on disk heatsinks and serial implanter platens. Novel evaluation techniques and custom engineered tools are used to investigate the surface interaction characteristics of multiple Elastomeric Silicone Coatings currently in use by the industry - specifically, friction and perpendicular stiction. These parameters are presented as methods to investigate the critical wafer load and unload function. Unique tools and test

  1. Advanced process control and novel test methods for PVD silicon and elastomeric silicone coatings utilized on ion implant disks, heatsinks and selected platens

    NASA Astrophysics Data System (ADS)

    Springer, J.; Allen, B.; Wriggins, W.; Kuzbyt, R.; Sinclair, R.

    2012-11-01

    Coatings play multiple key roles in the proper functioning of mature and current ion implanters. Batch and serial implanters require strategic control of elemental and particulate contamination which often includes scrutiny of the silicon surface coatings encountering direct beam contact. Elastomeric Silicone Coatings must accommodate wafer loading and unloading as well as direct backside contact during implant plus must maintain rigid elemental and particulate specifications. The semiconductor industry has had a significant and continuous effort to obtain ultra-pure silicon coatings with sustained process performance and long life. Low particles and reduced elemental levels for silicon coatings are a major requirement for process engineers, OEM manufacturers, and second source suppliers. Relevant data will be presented. Some emphasis and detail will be placed on the structure and characteristics of a relatively new PVD Silicon Coating process that is very dense and homogeneous. Wear rate under typical ion beam test conditions will be discussed. The PVD Silicon Coating that will be presented here is used on disk shields, wafer handling fingers/fences, exclusion zones of heat sinks, beam dumps and other beamline components. Older, legacy implanters can now provide extended process capability using this new generation PVD silicon - even on implanter systems that were shipped long before the advent of silicon coating for contamination control. Low particles and reduced elemental levels are critical performance criteria for the silicone elastomers used on disk heatsinks and serial implanter platens. Novel evaluation techniques and custom engineered tools are used to investigate the surface interaction characteristics of multiple Elastomeric Silicone Coatings currently in use by the industry - specifically, friction and perpendicular stiction. These parameters are presented as methods to investigate the critical wafer load and unload function. Unique tools and test

  2. Simulation Study Using an Injection Phase-locked Magnetron as an Alternative Source for SRF Accelerators

    SciTech Connect

    Wang, Haipeng; Plawski, Tomasz E.; Rimmer, Robert A.

    2015-09-01

    As a drop-in replacement for the CEBAF CW klystron system, a 1497 MHz, CW-type high-efficiency magnetron using injection phase lock and amplitude variation is attractive. Amplitude control using magnetic field trimming and anode voltage modulation has been studied using analytical models and MATLAB/Simulink simulations. Since the 1497 MHz magnetron has not been built yet, previously measured characteristics of a 2.45GHz cooker magnetron are used as reference. The results of linear responses to the amplitude and phase control of a superconducting RF (SRF) cavity, and the expected overall benefit for the current CEBAF and future MEIC RF systems are presented in this paper.

  3. Flexible free-standing TiO2/graphene/PVdF films as anode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Ren, H. M.; Ding, Y. H.; Chang, F. H.; He, X.; Feng, J. Q.; Wang, C. F.; Jiang, Y.; Zhang, P.

    2012-12-01

    Graphene composites were prepared by hydrothermal method using titanium dioxide (TiO2) adsorbed graphene oxide (GO) sheets as precursors. Free-standing hybrid films for lithium-ion batteries were prepared by adding TiO2/graphene composites to the polyvinylidene fluoride (PVdF)/N-methyl-2-pyrrolidone (NMP) solution, followed by a solvent evaporation technique. These films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and various electrochemical techniques. Flexible films show an excellent cycling performance, which was attributed to the interconnected graphene conducting network, which depressed the increasing of electric resistance during the cycling.

  4. Ion-induced oxidation of aluminum during reactive magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Kreiter, Oliver; Grosse-Kreul, Simon; Corbella, Carles; von Keudell, Achim

    2013-04-01

    Particle beam experiments were conducted in an ultra-high-vacuum vessel to mimic target poisoning during reactive magnetron sputtering of aluminum. Aluminum targets were exposed to quantified beams of argon ions, oxygen atoms and molecules, and aluminum vapour. The growth and etch rates were measured in situ by means of an Al-coated quartz crystal microbalance. The chemical state of the target surface was monitored in-situ by real-time Fourier transform infrared spectroscopy. The surface processes were modelled through a set of balance equations providing sputter yields and sticking coefficients. The results indicate that the oxygen uptake of the aluminum surface is enhanced by a factor 1 to 2 by knock-on implantation and that the deposition of aluminum is not affected by the oxidation state of the surface.

  5. Modeling of Magnetron Argon Plasma Issuing into Ambient Air

    NASA Astrophysics Data System (ADS)

    Li, Lin-Cun; Xia, Wei-Dong

    2008-01-01

    A mathematical model is presented to describe the heat transfer and fluid flow in a magnetron plasma torch, by means of a commercial computational fluid dynamics (CFD) code fluent. Specific calculations are presented for a gas-mixing system (i.e., an argon plasma discharging into an air environment), operating in a laminar mode. Numerical results show that an external axial magnetic field (AMF) may have a significant effect on the behavior of an arc plasma, i.e., the AMF will impel the plasma to retract axially and expand radially. In addition, the use of an AMF induces a strong air indraft at the torch spout, and the air mixing with the argon gas results in a marked increase in arc voltage. An increment in the amount of the oncoming argon gas restrains the quantity of the air indraft, and this should be responsible for a lower arc voltage in such an AMF torch when a larger gas inflow is used.

  6. Magnetron deposition of TCO films using ion beam

    NASA Astrophysics Data System (ADS)

    Asainov, O.; Umnov, S.; Chinin, A.

    2015-11-01

    Thin films of tin oxide (TO) were deposited on the glass substrates at room temperature using reactive magnetron sputtering at various oxygen partial pressures. After the deposition the films were irradiated with argon ions beam. The change of the optical and electrical properties of the films depending on the irradiation time was studied. Films optical properties in the range of 300-1100 nm were investigated by photometry as well as their structural properties were studied using X-ray diffraction. Diffractometric research showed that the films, deposited on a substrate, have a crystal structure, and after argon ions irradiation they become quasi-crystalline (amorphous). It was found that the transmission increases proportionally with the irradiation time, but the surface resistance -disproportionally.

  7. GaAs Films Prepared by RF-Magnetron Sputtering

    SciTech Connect

    L.H. Ouyang; D.L. Rode; T. Zulkifli; B. Abraham-Shrauner; N. Lewis; M.R. Freeman

    2001-08-01

    The authors reported on the optical absorption, adhesion, and microstructure of RF-magnetron sputtered films of hydrogenated amorphous and microcrystalline GaAs films for the 1 to 25 {micro}m infrared wavelength rate. Sputtering parameters which were varied include sputtering power, temperature and pressure, and hydrogen sputtering-gas concentration. TEM results show a sharp transition from purely amorphous GaAs to a mixture of microcrystalline GaAs in an amorphous matrix at 34 {+-} 2 C. By optimizing the sputtering parameters, the optical absorption coefficient can be decreased below 100 cm{sup -1} for wavelengths greater than about 1.25 {micro}m. These results represent the lowest reported values of optical absorption for sputtered films of GaAs directly measured by spectrophotometry for the near-infrared wavelength region.

  8. Microstructure of microwave dielectricthin films by RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Shi, Feng; Cui, Chuanwen

    2010-02-01

    The article describes the microstructure and morphological properties of microwave dielectric ceramic thin films. These thin films were successfully prepared on SiO 2 (1 1 0) single-crystal substrates by radio frequency magnetron-sputtering system. The microstructure and morphology of the thin films were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. The results show that the main phase is Ba 0.5Sr 0.5Nb 2O 6,which has a tetragonal perovskite structure, a long strip pattern, and uniform crystal-grain size of about 2-3 μm in length when annealed under 1150 °C for 30 min in an O 2 atmosphere. These thin films are of excellent crystallization quality, with a polycrystalline and dense structure.

  9. Magnetron with flux switching cathode and method of operation

    DOEpatents

    Aaron, D.B.; Wiley, J.D.

    1989-09-12

    A magnetron sputtering apparatus is formed with a plurality of cells each for generating an independent magnetic field within a different region in the chamber of the apparatus. Each magnetic field aids in maintaining an ion plasma in the respective region of the chamber. One of a plurality of sputtering material targets is positioned on an electrode adjacent to each region so that said ions strike the target ejecting some of the target material. By selectively generating each magnetic field, the ion plasma may be moved from region to region to sputter material from different targets. The sputtered material becomes deposited on a substrate mounted on another electrode within the chamber. The duty cycle of each cell can be dynamically varied during the deposition to produce a layer having a graded composition throughout its thickness. 5 figs.

  10. Magnetron with flux switching cathode and method of operation

    DOEpatents

    Aaron, David B.; Wiley, John D.

    1989-01-01

    A magnetron sputtering apparatus is formed with a plurality of cells each for generating an independent magnetic field within a different region in the chamber of the apparatus. Each magnetic field aids in maintaining an ion plasma in the respective region of the chamber. One of a plurality of sputtering material targets is positioned on an electrode adjacent to each region so that said ions strike the target ejecting some of the target material. By selectively generating each magnetic field, the ion plasma may be moved from region to region to sputter material from different targets. The sputtered material becomes deposited on a substrate mounted on another electrode within the chamber. The duty cycle of each cell can be dynamically varied during the deposition to produce a layer having a graded composition throughout its thickness.

  11. Full-Scale 3D Simulation of a sputtering magnetron

    NASA Astrophysics Data System (ADS)

    Walton, C. C.; Wilks, S. C.; Ayyaswamy, V.; Verboncoeur, J. P.; Parks, P. B.; Wu, W.; Zhou, C. D.; Stoltz, P. H.

    2010-11-01

    PIC simulations have been used to study ion energy distributions in magnetron plasmas, and coupled with other simulations to relate plasma processes to properties of sputtered films. The plasma is weakly ionized and exchanges heat with the background gas by scattering and charge-exchange reactions. Resulting heating of neutral background gas up to ˜1200K, leading to ˜5X rarefaction and increased plasma impedance, was studied with coupled PIC and Direct Simulation Monte Carlo (DSMC) simulations. Effects of scaling the PIC simulations from 0.1X to 1X physical size, and modifying the plasma potential by a dc substrate bias, will be presented. Comparison to experimental I-V relations and importance for roughness and density of sputtered films will be discussed.

  12. Analysis of Low Frequency Oscillations in Magnetron Injection Guns

    NASA Astrophysics Data System (ADS)

    Pu, Youlei; Luo, Yong; Yan, Ran; Liu, Guo; Jiang, Wei

    2012-02-01

    In our gyro-TWT experiments, low-frequency oscillations (LFOs) had been observed. LFOs is a physical phenomenon usually caused by the electrons trapped between the magnetron injection guns (MIGs) and the interaction region. In this paper, the formation procedure and physical mechanism of LFOs are reported. Available methods including optimizing the magnetic field distribution in the beam compression region and loading bevel cuts on the second anode are involved to capture the trapped electrons, suppress the LFOs and improve the helical electron beam quality. Simulations and experimental results are in good agreement with each other and also reveal the reasonableness of this means. Finally, the influence of current capture ratio on LFOs and the beam quality are studied. With the current capture ratio increasing, the amplitude of LFOs decreases, the pitch factor maintains a constant about 1.2 and we also demonstrate a low transverse velocity spread about 3%.

  13. RF magnetron sputtering of thick platinum coatings on glass microspheres

    SciTech Connect

    Meyer, S.F.; Hsieh, E.J.; Burt, R.J.

    1980-05-28

    Thick platinum coatings on glass microspheres are needed for proposed Laser Fusion targets. The spherical nature of these substrates coupled with the small dimensions (approx. 100 ..mu..m OD) make it difficult to achieve a smooth and uniform coating. Coating problems encountered include a rough surface and porous microstructure from the oblique incidence and lack of temperature and bias control, clumping of the microspheres causing non-uniformities, and particle accumulation causing cone defects. Sputtering parameters significantly affecting the coatings include total pressure, DC substrate bias, and the addition of doping gases. Using an ultrasonic vibrating screened cage and RF magnetron Sputtergun, we have successfully batch coated microspheres with up to 6 ..mu..m of Pt, with a surface roughness of 200 nm, thickness non-concentricity of 300 nm, and density greater than 98% of bulk Pt.

  14. Experimental evidence of warm electron populations in magnetron sputtering plasmas

    SciTech Connect

    Sahu, B. B. Han, Jeon G.; Kim, Hye R.; Ishikawa, K.; Hori, M.

    2015-01-21

    This work report on the results obtained using the Langmuir probe (LP) measurements in high-power dc magnetron sputtering discharges. Data show clear evidence of two electron components, such as warm and bulk electrons, in the sputtering plasma in a magnetic trap. We have also used optical emission spectroscopy diagnostic method along with LP to investigate the plasma production. Data show that there is a presence of low-frequency oscillations in the 2–3 MHz range, which are expected to be generated by high-frequency waves. Analysis also suggests that the warm electrons, in the plasmas, can be formed due to the collisionless Landau damping of the bulk electrons.

  15. Highly conducting ZnSe films by reactive magnetron sputtering

    NASA Technical Reports Server (NTRS)

    Nouhi, A.; Stirn, R. J.

    1986-01-01

    This paper presents the results of an effort to deposit high-conductivity ZnSe on glass and conducting SnO2-coated glass substrates by reactive magnetron sputter deposition, using pure metal sputter targets of Zn and dopants such as In, Ga, and Al. Clear yellow ZnSe films were successfully obtained. By using substrate temperatures as low as 150 C, cosputtered dopants, and sputter parameters and H2Se injection rates which maximize the Zn-to-Se ratio in the films, ZnSe bulk resistivities have been lowered by up to seven orders of magnitude, reaching values as low as 20 ohm cm. The most effective dopant to data has been In, cosputtered with Zn in amounts leading to In atomic concentrations as high as 1.4 percent. Atomic-absorption measurements show an average 49.9/48.9 ratio of Zn to Se.

  16. Spatiotemporal synchronization of drift waves in a magnetron sputtering plasma

    SciTech Connect

    Martines, E.; Zuin, M.; Cavazzana, R.; Antoni, V.; Serianni, G.; Spolaore, M.; Vianello, N.; Adámek, J.

    2014-10-15

    A feedforward scheme is applied for drift waves control in a magnetized magnetron sputtering plasma. A system of driven electrodes collecting electron current in a limited region of the explored plasma is used to interact with unstable drift waves. Drift waves actually appear as electrostatic modes characterized by discrete wavelengths of the order of few centimeters and frequencies of about 100 kHz. The effect of external quasi-periodic, both in time and space, travelling perturbations is studied. Particular emphasis is given to the role played by the phase relation between the natural and the imposed fluctuations. It is observed that it is possible by means of localized electrodes, collecting currents which are negligible with respect to those flowing in the plasma, to transfer energy to one single mode and to reduce that associated to the others. Due to the weakness of the external action, only partial control has been achieved.

  17. Influence of RF power on magnetron sputtered AZO films

    SciTech Connect

    Agarwal, Mohit; Modi, Pankaj; Dusane, R. O.

    2013-02-05

    Al-doped Zinc Oxide (AZO) transparent conducting films are prepared on glass substrate by RF magnetron sputtering under different RF power with a 3 inch diameter target of 2 wt%Al{sub 2}O{sub 3} in zinc oxide. The effect of RF power on the structural, optical and electrical properties of AZO films was investigated by X-ray Diffraction (XRD), Hall measurement and UV-Visible spectrophotometry. The XRD data indicates a preferential c-axis orientation for all the films. All films exhibit high transmittance (<90%) in visible region. Films deposited at 60 W power exhibit lowest resistivity of 5.7 Multiplication-Sign 10{sup -4}{omega}cm. Such low-resistivity and high-transmittance AZO films when prepared using low RF power at room temperature could find important applications in flexible electronics.

  18. Characterization on RF magnetron sputtered niobium pentoxide thin films

    SciTech Connect

    Usha, N.; Sivakumar, R.; Sanjeeviraja, C.

    2014-10-15

    Niobium pentoxide (Nb{sub 2}O{sub 5}) thin films with amorphous nature were deposited on microscopic glass substrates at 100°C by rf magnetron sputtering technique. The effect of rf power on the structural, morphological, optical, and vibrational properties of Nb{sub 2}O{sub 5} films have been investigated. Optical study shows the maximum average transmittance of about 87% and the optical energy band gap (indirect allowed) changes between 3.70 eV and 3.47 eV. AFM result indicates the smooth surface nature of the samples. Photoluminescence measurement showed the better optical quality of the deposited films. Raman spectra show the LO-TO splitting of Nb-O stretching of Nb{sub 2}O{sub 5} films.

  19. Dual-Income Families.

    ERIC Educational Resources Information Center

    McKitric, Eloise J.

    The impact of economic conditions on two-earner families was examined. Three family types were studied: (1) dual-career family--both the husband and wife are in the labor force but in occupations classified as professional-technical or managerial; (2) dual-earner--both the husband and wife are in the labor force; and (3) traditional family--the…

  20. The Dual Career Family.

    ERIC Educational Resources Information Center

    Gurtin, Lee

    1980-01-01

    The dual career couple is forced to make a series of choices and compromises that impact the realms of marriage and career. The dilemmas that confront dual career marriages can be overcome only by compromise, accommodation, and mutual understanding on the part of the individuals involved. A revamping of human resources and recruitment programs is…

  1. Dual drive actuators

    NASA Technical Reports Server (NTRS)

    Packard, D. T.

    1982-01-01

    A new class of electromechanical actuators is described. These dual drive actuators were developed for the NASA-JPL Galileo Spacecraft. The dual drive actuators are fully redundant and therefore have high inherent reliability. They can be used for a variety of tasks, and they can be fabricated quickly and economically.

  2. Dual Enrollment Academy Programs

    ERIC Educational Resources Information Center

    Gonzalez, Nicolas; Chavez, Guadalupe

    2009-01-01

    Dual Enrollment Engineering (DEEA) and Medical Science (DEMSA) Academies are two-year dual enrollment programs for high school students. Students explore engineering and medical careers through college coursework. Students prepare for higher education in engineering and medical fields while completing associate degrees in biology or engineering…

  3. Magnetron-Sputtered YSZ and CGO Electrolytes for SOFC

    NASA Astrophysics Data System (ADS)

    Solovyev, A. A.; Shipilova, A. V.; Ionov, I. V.; Kovalchuk, A. N.; Rabotkin, S. V.; Oskirko, V. O.

    2016-03-01

    Reactive magnetron sputtering has been used for deposition of yttria-stabilized ZrO2 (YSZ) and gadolinium-doped CeO2 (CGO) layers on NiO-YSZ commercial anodes for solid oxide fuel cells. To increase the deposition rate and improve the quality of the sputtered thin oxide films, asymmetric bipolar pulse magnetron sputtering was applied. Three types of anode-supported cells, with single-layer YSZ or CGO and YSZ/CGO bilayer electrolyte, were prepared and investigated. Optimal thickness of oxide layers was determined experimentally. Based on the electrochemical characteristics of the cells, it is shown that, at lower operating temperatures of 650°C to 700°C, the cells with single-layer CGO electrolyte are most effective. The power density of these fuel cells exceeds that of the cell based on YSZ single-layer electrolyte at the same temperature. Power densities of 650 mW cm-2 and 500 mW cm-2 at 700°C were demonstrated by cells with single-layer YSZ and CGO electrolyte, respectively. Significantly enhanced maximum power density was achieved in a bilayer-electrolyte single cell, as compared with cells with a single electrolyte layer. Maximum power density of 1.25 W cm-2 at 800°C and 1 W cm-2 at 750°C under voltage of 0.7 V were achieved for the YSZ/CGO bilayer electrolyte cell with YSZ and CGO thickness of about 4 μm and 1.5 μm, respectively. This signifies that the YSZ thin film serves as a blocking layer to prevent electrical current leakage in the CGO layer, leading to the overall enhanced performance. This performance is comparable to the state of the art for cells based on YSZ/CGO bilayer electrolyte.

  4. Magnetron sputtered nanostructured cadmium oxide films for ammonia sensing

    SciTech Connect

    Dhivya, P.; Prasad, A.K.; Sridharan, M.

    2014-06-01

    Nanostructured cadmium oxide (CdO) films were deposited on to glass substrates by reactive dc magnetron sputtering technique. The depositions were carried out for different deposition times in order to obtain films with varying thicknesses. The CdO films were polycrystalline in nature with cubic structure showing preferred orientation in (1 1 1) direction as observed by X-ray diffraction (XRD). Field-emission scanning electron microscope (FE-SEM) micrographs showed uniform distribution of grains of 30–35 nm size and change in morphology from spherical to elliptical structures upon increasing the film thickness. The optical band gap value of the CdO films decreased from 2.67 to 2.36 eV with increase in the thickness. CdO films were deposited on to interdigitated electrodes to be employed as ammonia (NH{sub 3}) gas sensor. The fabricated CdO sensor with thickness of 294 nm has a capacity to detect NH{sub 3} as low as 50 ppm at a relatively low operating temperature of 150 °C with quick response and recovery time. - Highlights: • Nanostructured CdO films were deposited on to glass substrates using magnetron sputtering. • Deposition time was varied in order to obtain films with different thicknesses. • The CdO films were polycrystalline in nature with preferred orientation along (1 1 1) direction. • The optical bandgap values of the films decreased on increasing the thickness of the films. • CdO films with different thickness such as 122, 204, 294 nm was capable to detect NH{sub 3} down to 50 ppm at operating temperature of 150 °C.

  5. Magnetron-Sputtered YSZ and CGO Electrolytes for SOFC

    NASA Astrophysics Data System (ADS)

    Solovyev, A. A.; Shipilova, A. V.; Ionov, I. V.; Kovalchuk, A. N.; Rabotkin, S. V.; Oskirko, V. O.

    2016-08-01

    Reactive magnetron sputtering has been used for deposition of yttria-stabilized ZrO2 (YSZ) and gadolinium-doped CeO2 (CGO) layers on NiO-YSZ commercial anodes for solid oxide fuel cells. To increase the deposition rate and improve the quality of the sputtered thin oxide films, asymmetric bipolar pulse magnetron sputtering was applied. Three types of anode-supported cells, with single-layer YSZ or CGO and YSZ/CGO bilayer electrolyte, were prepared and investigated. Optimal thickness of oxide layers was determined experimentally. Based on the electrochemical characteristics of the cells, it is shown that, at lower operating temperatures of 650°C to 700°C, the cells with single-layer CGO electrolyte are most effective. The power density of these fuel cells exceeds that of the cell based on YSZ single-layer electrolyte at the same temperature. Power densities of 650 mW cm-2 and 500 mW cm-2 at 700°C were demonstrated by cells with single-layer YSZ and CGO electrolyte, respectively. Significantly enhanced maximum power density was achieved in a bilayer-electrolyte single cell, as compared with cells with a single electrolyte layer. Maximum power density of 1.25 W cm-2 at 800°C and 1 W cm-2 at 750°C under voltage of 0.7 V were achieved for the YSZ/CGO bilayer electrolyte cell with YSZ and CGO thickness of about 4 μm and 1.5 μm, respectively. This signifies that the YSZ thin film serves as a blocking layer to prevent electrical current leakage in the CGO layer, leading to the overall enhanced performance. This performance is comparable to the state of the art for cells based on YSZ/CGO bilayer electrolyte.

  6. Heat pipe - Design and fabrication for a magnetron and TWT of radar systems

    NASA Astrophysics Data System (ADS)

    Alesse, R.; Corsi, U.; Malagoli, G.

    1983-10-01

    The present investigation is concerned with an employment of heat pipes instead of local ventilator systems in two cases, including a magnetron and a traveling-wave tube (TWT). In the case of the magnetron utilizing a ventilation system, it was found that much noise was produced by the general ventilation system, the magnetron centrifugal fan, and the air motion in the magnetron. In order to solve the noise problem, the installation of heat pipes was considered. Details related to the design and the appropriate installation of the heat pipe are discussed. The second application of a heat pipe is related to the design of a cold plate for draining the heat generated by the operation of a 1200 W TWT in a naval cabinet. The achievement of a low noise level and a low TWT collector temperature were the objectives which led to the consideration of an employment of heat pipes in this case.

  7. PIC simulation of high efficiency and high power 14 vane industrial magnetron

    NASA Astrophysics Data System (ADS)

    Vyas, Sandeep; Maurya, Shivendra; Singh, V. V. P.

    2016-03-01

    This paper presents a 3D Particle in cell (PIC) simulation of a CW 2.450±0.050 GHz 10 kW industrial magnetron. The electromagnetic and PIC simulation of magnetron has been carried out using CST microwave studio andCST particle studio. A virtual prototype of 14 vane magnetron has been simulated on computer. The cold frequency of magnetron is found 2.495 GHz. The unloaded quality factor and circuit efficiency are found 1970 and 92% from electromagnetic simulation. The output power is achieved 12.4 KW for anode voltage 12.7 kV and magnetic field 2900 Gauss. The anode current is found anode current 1.22 A. The total efficiency is 78.76 %.

  8. CdS Film Thickness Characterization By R. F. Magnetron Sputtering

    SciTech Connect

    Hashim, Uda; Rahman, Kasim Abdul

    2009-06-01

    In this work, cadmium sulphide (CdS) target with 99.999% purity was used as a target in RF magnetron sputtering. The sputtering experiment was conducted onto silicon oxide substrates at different temperatures ranging from 200 deg. C to 400 deg. C in 50 deg. C steps, using a capacitive coupled magnetron cathode with 13.65 MHz that at higher magnetron power. After all investigations, it was concluded that 300 deg. C substrate temperature is suitable for producing CdS films on silicon wafer with RF magnetron sputtering and the examined properties (good crystallinity and low resistivity) of this film show its feasibility for technological purposes, especially for light sensor cells.

  9. Magnetron sputtering as a method of thin-film catalyst development for electrochemical sensors

    NASA Astrophysics Data System (ADS)

    Medvedeva, E. A.

    2016-07-01

    The aim of this work was to develop a thin-film Pt/C catalyst on the fluoroplastic substrates by means of the magnetron sputtering method in order to use as reference and working electrodes of electrochemical cells.

  10. Growth of fullerene-like carbon nitride thin solid films by reactive magnetron sputtering; role of low-energy ion irradiation in determining microstructure and mechanical properties

    NASA Astrophysics Data System (ADS)

    Neidhardt, J.; Czigány, Zs.; Brunell, I. F.; Hultman, L.

    2003-03-01

    Fullerene-like (FL) carbon nitride (CNx) films were deposited on Si (100) substrates by dc reactive, unbalanced, magnetron sputtering in a N2/Ar mixture from a high-purity pyrolythic graphite cathode in a dual-magnetron system with coupled magnetic fields. The N2 fraction in the discharge gas (0%-100%) and substrate bias (-25 V; -40 V) was varied, while the total pressure (0.4 Pa) and substrate temperature (450 °C) was kept constant. The coupled configuration of the magnetrons resulted in a reduced ion flux density, leading to a much lower average energy per incorporated particle, due to a less focused plasma as compared to a single magnetron. This enabled the evolution of a pronounced FL microstructure. The nitrogen concentration in the films saturated rapidly at 14-18 at. %, as determined by elastic recoil analysis, with a minor dependence on the discharge conditions. No correlations were detected between the photoelectron N1s core level spectra and the different microstructures, as observed by high-resolution electron microscopy. A variety of distinct FL structures were obtained, ranging from structures with elongated and aligned nitrogen-containing graphitic sheets to disordered structures, however, not exclusively linked to the total N concentration in the films. The microstructure evolution has rather to be seen as in equilibrium between the two competing processes of adsorption and desorption of nitrogen-containing species at the substrate. This balance is shifted by the energy and number of arriving species as well as by the substrate temperature. The most exceptional structure, for lower N2 fractions, consists of well-aligned, multi-layered circular features (nano-onions) with an inner diameter of approximately 0.7 nm and successive shells at a distance of ˜0.35 nm up to a diameter of 5 nm. It is shown that the intrinsic stress formation is closely linked with the evolution and accommodation of the heavily bent fullerene-like sheets. The FL CNx