Ion Beam Assisted Deposition Method Research Articles

Effect of PVD deposition method on indentation and friction wear characteristics with hydrogen embrittlement of CrN coated stainless steel for electric vehicle hydrogen valves

In this investigation, a chromium nitride layer was deposited on general austenite stainless steel (UNS S31603) by means of the physical vapor deposition coating method to improve the hardness, wear resistance, and hydrogen embrittlement resistance. Accordingly, the purpose of this investigation is to study the effect of different physical deposition methods on mechanical characteristics due to hydrogen embrittlement. Both the indentation and friction characteristics of the chromium nitride layer with in response to hydrogen embrittlement were examined. The ion beam-assisted deposition (IBAD) and arc ion plating (AIP) methods were used to densely deposit the coating layer with a thickness of approximately 2.0∼2.5 μm, and the hardness increased by around 1180.9 HV and 1638.6 HV, respectively, when compared with the base material (292.6 HV). In terms of the coating layer deposited using the IBAD method, all the base material was exposed after hydrogen embrittlement for 3 h, whereas in the case of the coating deposited using the AIP method, the base material began to be exposed locally following hydrogen embrittlement for 12 h. For the IBAD- and AIP-deposited coatings, the average friction coefficient was calculated as 0.52 and 0.34, respectively. In the case of the coating layer deposited using the IBAD method, the average friction coefficient increased by 0.29 after hydrogen embrittlement for 3 h, whereas the average friction coefficient of the coating layer deposited using the AIP method increased by 0.04 after hydrogen embrittlement for 48 h. Therefore, it can be seen that the AIP method is significantly better than IBAD in terms of mechanical characteristics with hydrogen embrittlement.

Effects of nano-engineered surfaces on osteoblast adhesion, growth, differentiation, and apoptosis

Modifying implant surfaces to improve their biocompatibility by enhancing osteoblast activation, growth, differentiation, and induction of greater bone formation with stronger attachments should result in improved outcomes for total joint replacement surgeries. This study tested the hypothesis that nano-structured surfaces, produced by the ion beam-assisted deposition method, enhance osteoblast adhesion, growth, differentiation, bone formation, and maturation. The ion beam-assisted deposition technique was employed to deposit zirconium oxide films on glass substrates. The effects of the ion beam-assisted deposition technique on cellular functions were investigated by comparing adhesion, proliferation, differentiation, and apoptosis of the human osteosarcoma cell line SAOS-2 on coated versus uncoated surfaces. Ion beam-assisted deposition nano-coatings enhanced initial cell adhesion assessed by the number of 4′,6-diamidino-2-phenylindole–stained nuclei on zirconium oxide nano-coated surfaces compared to glass surfaces. This nano-modification also increased cell proliferation as measured by mitochondrial dehydrogenase activity. Moreover, the ion beam-assisted deposition technique improved cell differentiation as determined by the formation of mineralized bone nodules and by the rate of calcium deposition, both of which are in vitro indicators of the successful bone formation. However, programmed cell death assessed by Annexin V staining and flow cytometry was not statistically significantly different between nano-surfaces and glass surfaces. Overall, the results indicate that nano-crystalline zirconium oxide surfaces produced by the ion beam-assisted deposition technique are superior to uncoated surfaces in supporting bone cell adhesion, proliferation, and differentiation. Thus, surface properties altered by the ion beam-assisted deposition technique enhanced bone formation and may increase the biocompatibility of bone cell–associated surfaces.

Microstructural and corrosion resistance characterisation of NiTi shape memory alloy modified at low-temperature plasma with carbon coatings produced via RFCVD and IBAD methods

ABSTRACTNiTi shape memory alloy, both before and after low-temperature oxynitriding under glow discharge conditions combined with the production of a nano-sized outer carbon coating, was investigated. The study compares two types of carbon coatings: produced via the RFCVD (radio frequency chemical vapour deposition) and IBAD (ion beam-assisted deposition) methods. The latter was also enriched by randomly distributed silver nanoparticles. The study showed slight changes in roughness parameters and increased corrosion resistance after surface treatment processes. The largest impedance module and corrosion potential and the smallest density of corrosion current were achieved for samples with a carbon coating produced via the RFCVD process. The presented surface modifications using hybrid processes can extend the use of NiTi alloy in medicine due to the increased biocompatibility.

Surface nano-modification by ion beam-assisted deposition alters the expression of osteogenic genes in osteoblasts.

Biomaterials with enhanced biocompatibility are favored in implant studies to improve the outcomes of total joint replacement surgeries. This study tested the hypothesis that nano-structured surfaces for orthopedic applications, produced by the ion beam-assisted deposition method, would enhance osteointegration by altering the expression of bone-associated genes in osteoblasts. The ion beam-assisted deposition technique was employed to deposit nano-films on glass or titanium substrates. The effects of the ion beam-assisted deposition produced surfaces on the human osteosarcoma cell line SAOS-2 at the molecular level were investigated by assays of adhesion, proliferation, differentiation, and apoptosis on coated surfaces versus uncoated cobalt-chrome, as the control. Ion beam-assisted deposition nano-coatings enhanced bone-associated gene expression at initial cell adhesion, proliferation, and differentiation compared to cobalt-chrome surfaces as assessed by polymerase chain reaction techniques. Increased cell proliferation was observed using a nuclear cell proliferation-associated antigen. Moreover, enhanced cell differentiation was determined by alkaline phosphatase activity, an indicator of bone formation. In addition, programmed cell death assessed by annexin V staining and flow cytometry was lower on nano-surfaces compared to cobalt-chrome surfaces. Overall, the results indicate that nano-coated surfaces produced by the ion beam-assisted deposition technique for use on implants were superior to orthopedic grade cobalt-chrome in supporting bone cell adhesion, proliferation, and differentiation and reducing apoptosis. Thus, surface properties altered by the ion beam-assisted deposition technique should enhance bone formation and increase the biocompatibility of bone cell-associated surfaces.

Microstructure, magnetic properties and the giant magnetoimpedance effect of amorphous CoSiB thin films deposited by different preparation methods

Controlling the film thickness and soft magnetic properties are the two key factors for giant magnetoimpedance effect (GMI). In this paper, we reported that the ion beam assisted deposition (IBAD) is useful for preparing the GMI materials thin films. The CoSiB thin films with a thickness of a few micron prepared by IBAD shows a very superior ability to combine with the substrate compared with DC and RF sputtering method. Meanwhile, the thick CoSiB thin film by IBAD method also exhibits a good soft magnetic property, but the grown CoSiB films by RF sputtering showed thickness-driven spin orientation behavior in thick CoSiB films leading to the deterioration of its soft magnetic properties. Thus, a Ti layer was introduced to eliminate thickness-driven magnetic behavior in thick FeNi films and thereby preserve their magnetic softness. Furthermore, we found that the GMI effect of CoSiB films prepared by IBAD is stronger than that of magnetron sputtering. Especially, an excellent GMI phase effect in a low frequency range was observed in the CoSiB film prepared by IBAD, which was beneficial for high sensitive magnetic sensor design. In the end, x-ray diffraction and x-ray photoelectron spectroscopy analyses suggest that all the thin films prepared by the sputtering or IBAD method show the metallic glasses structure, thus the origin of the difference in magnetism is may be due to their different short-order structure.

Electrocatalysts for Ethanol and Methanol Oxidation Prepared by Ion Beam Assisted Deposition of Platinum and Rare Earths Metals on Carbon Fiber Paper Catalyst Carriers

Active layers of electrocatalysts were prepared by ion beam assisted deposition (IBAD) of platinum and one of rare earth metals (Ce, Gd, Dy, Yb) on the carbon based Toray Carbon Fiber Paper TGP-H-060 T (TorayCFP) and AVCarb® Carbon Fiber Paper Р50 (AVCarbCFP) catalysts carriers with the aim of electrocatalysts production for direct methanol and ethanol oxidation fuel cells (DMFC, DEFC) with polymer membrane electrolyte. Formation of layers in IBAD mode, by means of the deposition of metal and mixing of precipitating layer with the substrate by accelerated (U = 5 kV) ions of the same metal, was carried out. In this process, a neutral fraction of metal vapor and ionized plasma of vacuum pulsed electric arc discharge were used. According to scanning electron microscopy, electron probe microanalysis, X-ray fluorescence analysis and Rutherford backscattering spectrometry investigations atoms of deposited metals, carbon substrates, and oxygen as impurity enter into the composition of layers. The thickness of the prepared catalytic layers is ~30 nm; content of platinum atoms in the layers – ~2×1016 cm–2, or much less than 0.05 mgPt/cm2. Properties of the prepared electrocatalysts were investigated by cyclic voltammetry in 1M CH3OH + 0.5M H2SO4 and 1M C2H5OH + 0.5M H2SO4 solutions. It was established that the prepared electrocatalysts show activity in the processes of electrochemical oxidation of methanol and ethanol. The inclusion of the rare earth metal in the composition of formed layers enhances the activity of electrocatalysts in a multistage process of oxidation of alcohols. Moreover the activity of prepared electrocatalysts in the oxidation of more complex molecules of ethanol is higher than the activity in oxidation reaction of methanol. The advantages of proposed IBAD method are as follows: possibility of forming a cohesive catalytically active layer on a carbon substrate at low platinum consumption; one stage of deposition of each of metals a comparison against multistage traditional chemical methods of catalysts preparation. Figure 1

Approaches in controllable generation of artificial pinning center in REBa2Cu3Oy-coated conductor for high-flux pinning

This paper reviews the progress of studies to determine optimum shapes of the artificial pinning center (APC) of REBa2Cu3Oy thin films and coated conductors towards superconducting magnets operating at temperatures of 77 K or less. Superconducting properties vary depending on the kind and quantity of BaMO3 materials. Therefore, we study changes in the shapes of nanorods that are due to the difference in the quality of additives and growth temperature. In addition, we aim to control the APC using an optimum shape that matches the operating temperature. In particular, we describe the shape control of nanorods in SmBCO thin films and coated conductors by employing lower temperature growth (LTG) technology using seed layers. From the cross-sectional transmission electron microscopy observations, we confirmed that using the LTG method, the BaHfO3 (BHO) nanorods, which were comparatively thin and short in length, formed a firework structure in the case of SmBCO films with coated conductors. The superconducting properties in the magnetic field of the SmBCO-coated conductor with the optimum amount of BHO showed that = 1.6 TN m−3 on a single crystalline substrate and 1.5 TN m−3 on metallic substrate with a biaxially textured MgO layer fabricated by ion-beam assisted deposition method tape 4.2 K.

Electrocatalysts for Direct Alcohol Oxidation Fuel Cells Prepared Using Ion Beam Assisted Deposition Technique

Active layers of the electrocatalysts for oxidation of methanol and ethanol were prepared by ion beam assisted deposition (IBAD) of platinum and activating rare earths metals (Ce, Yb) onto carbon (AVCarb® Carbon Fiber Paper Р50 and Toray Carbon Fiber Paper TGP-H-060 Т) supports. The deposition method is characterized by the use of deposited-metal ions as assisting ions. Metal deposition and mixing between the precipitable layer and surface of the substrate by accelerated ions of the same metal were carried out on the experimental unit from a neutral vapor fraction and the vacuum-arc discharge plasma of a pulsed electric arc ion source, respectively. Ion accelerating voltage is 10 kV; vacuum – 10– 2 Pa. Investigation of the composition and microstructure of layers was carried out by RBS, SEM, EPMA and XRF methods. It has been established that the obtained catalytic layers contain atoms of the deposited metals and substrate material, as well as impurity oxygen atoms; their thickness reaches ~30–100 nm. Content of platinum atoms in the layers is ~2×1016 cm–2, concentration of deposited metals atoms in the maximum of distribution equals about a few at.%. According to investigations with use of cyclic voltammetry the electrocatalysts with prepared layers exhibited high catalytic activity in the reactions of electrochemical oxidation of methanol and ethanol, which form the basis for the principle of operation of low temperature fuel cells (DMFC and DEFC) (Figure 1). Figure 1. Cyclic voltammograms in the ethanol comprising solution of electrocatalyst prepared using ion beam deposition of ytterbium and platinum onto Toray Carbon Fiber Paper TGP-H-060 Т In comparison with the traditional multistage chemical methods of preparation of the deposited catalysts, the proposed IBAD method appears to be promising and often more preferable. It allows of the introduction of micro amounts of a doping impurity in the near-surface of a substrate under non equilibrium conditions and of the formation of cohesive catalytic layers at ultra-low platinum consumption. Figure 1

Low friction Ti-B coatings deposited by dual beam IBAD method for wear resistant applications

Thin Ti-B coatings of 500 nm in thickness were deposited by dual beam ion beam assisted deposition method (DB IBAD) on the surfaces of sintered α-Al2O3 (with 1% vol. MgO) cutting inserts. Deposition of Ti-B coating was conducted in vacuum. Two beams of Ar+ ions were applied of the same energy of ~10 keV. First ion beam was directed to TiB2 target at angle 67 and used for sputtering, the second one was directed perpendicularly to the surface of alumina substrate. XPS was applied to investigate chemical bonds in Ti-B coatings. Detailed spectra of B1s and Ti 2p indicated the presence of TiB2, TiO2 and B2O3. Mechanical properties of coated and uncoated alumina composites were examined by nanoindentation test using diamond indenter of Berkovich-type geometry, loaded in range 0.5 mN to 50 mN. The frictionwear performance of coated alumina were examined in ball-on-disc test using an alumina and a 100Cr6 steel balls as counterparts, loaded at 1 N. Cutting test was carried out in longitudinal turning of 100Cr6 steel shaft without use of any liquid coolant. Coated alumina inserts were harder and more resistant to wear than uncoated ones. The highest hardness of 45 GPa, was calculated by Oliver & Pharr method for coated sample tested under the load of 1 mN. It was almost 3 times the value calculated for uncoated substrate (16.5 GPa). The wear mechanism of Ti-B coated alumina was of abrasive type with alumina ball and of mixed abrasive and adhesive type in the case of friction contact with the steel ball. SEM observation of the surface of Ti-B coated alumina tools after turning revealed the presence of a liquid phase at the worn edge.

Ion Beam Assisted Deposition Enhanced Thermoelectric Properties (with Figure of Merit Above 3.0)

Ion Beam Assisted Deposition (IBAD) was used to process a thermoelectric materials system, with high volume fraction and high thermoelectric figure of merit, based on the interaction of composites of two metal nanocrystals in silica substrate prepared by a multilayer structure having alternate layers of metal/material mixture. The alternate layers component of this work either has gold or silver content. The deposited layered structure was bombarded during deposition by 500eV to 10keV argon ions in order to produce nanoclusters in each layer. Using the IBAD method we obtained a much larger volume fraction, compared to our previous work, and a resulting thermal conductivity as low as 1.2 (W/m.k), electrical conductivity nearly as high as 90,000 (1/Ohm.m), square of Seebeck Coefficient as high as 1.37 x 10-7 (V/k)2 at 350K, which translates to a Figure of Merit as high as 3.6.

Simple Mathematical Models of High Energy Ion Beam Assisted Deposition Concentration Profiles in Binary Thin Films

Mathematical models of composed high energy ion beam assisted deposition (IBAD) concentration profiles of implanted component in binary thin films are described. Yields of the backscattered ions and sputtering of the deposited component are considered. A Gaussian probability density is assumed to apply to the ion range distribution. The construction of concentration profiles of various shapes is considered. These profiles should of course be constructed based on continuous changes of the process parameters, but certain technical problems can arise with this continuous parameter changes. Therefore, it has been assumed that the changes to the process parameters are discrete and proceed in several steps. The resulting mathematical models are combinations of error functions. Mathematical models can be used as regression functions for the determination of some parameters, e.g., the sputtering yield. Based on the mathematical model the gradient concentration profile of nitrogen in the SiNx film was experimentally produced by the IBAD method, measured by Rutherford backscattering spectroscopy and compared with the mathematical model.

Study on design and deposition of minus filters for laser protection application

Minus filters are by definition filters that eliminate one wavelength band from a spectrum and transmits at both shorter and longer wavelengths. Such filters would be useful in such optical systems for rejecting a laser threat while transmitting others. Paper focused on use the equivalent-layer concept to design minus filters. According to design 532nm minus filter and 1064nm minus filter were deposited by ion beam assisted deposition method. Results show that the filter was provided with good performance and environmental stability. The results of damage threshold of coating for 10ns pulse: 859MW/cm2.

Characterization of InN Thin Films Grown by IBAD Method

The optical and electrical properties of nanostructured indium nitride (InN) thin films are studied in this work. Indium nitride films has been the subject of intensive research in the past few years due to its potential applications in optoelectronic area, such as solar cells and photo sensors. The primary objective of this work is to study the effects of deposition temperature on the crystallinity and morphology of these films. InN thin films were grown at room temperature (RT) and at 300 {degree sign}C using the Ion Beam Assisted Deposition (IBAD) method. The XRD patterns revealed that the room temperature deposited films were amorphous. Films formed at 300 {degree sign}C showed two peaks around 31{degree sign} (wurtzite-type InN 002) and around 33{degree sign} (metallic In 101). The thickness, roughness and deposition rate of the InN films were measured by high step meter and ellypsometer. In current versus voltage (IxV) analyses, all samples show semiconductor characteristics.

Effects of assisting and sputtering ion current on ion beam assisted deposition textured yttria stabilized zirconia buffer layers of coated conductors

Biaxially textured yttria stabilized zirconia (0 0 1) thin films were fabricated on untextured hastelloy substrates by ion beam assisted deposition method. The effects of assisting beam current density J a and sputtering beam current density J s on the textures of the films were studied. The results indicate that as J a or J s increase, both the out-of-plane and the in-plane textures are improved initially, and then degrade. The results can be attributed to anisotropic damage and selective sputtering effect of assisting ions. At the same ion-to-atom arrival ratio r, which is reflected with J a / J s value, lower deposition rate can enhance the biaxial texture.

A competition between (0 0 1) and (0 1 1) alignments in yttria stabilized zirconia thin films fabricated by ion beam assisted deposition

Biaxially textured yttria stabilized zirconia (YSZ) thin films, were deposited on glass substrates by ion beam assisted deposition method with different deposition time. As contrasts, films were also fabricated without assisting ion beam. The orientation properties of the films were characterized by X-ray diffraction. A comparative study shows that there is a competition between (0 0 1) and (0 1 1) alignments during the growth process. Assisting ions make the films (0 0 1)-advantaged and biaxially textured. The competitive growth and the orientation development are explained by selective resputtering and anisotropic damage on growing films induced by assisting ions.

Low-temperature formation of silicon dioxide films by oxygen cluster ion beam assisted deposition

Silicon dioxide films were formed by the cluster ion beam assisted deposition method. An oxygen cluster ion beam was irradiated while a silicon monoxide vapor was deposited on a substrate at room temperature. The deposited films were oxidized to form silicon dioxide films when the beam current density of the oxygen cluster ion beam was larger than 500 nA/cm 2 and the acceleration voltage of the oxygen cluster ion beam was higher than 3 kV.

Effects of calcium phosphate coating to SLA surface implants by the ion-beam-assisted deposition method on self-contained coronal defect healing in dogs

The aim of this study was to evaluate the healing of self-contained coronal defects on a sand-blasted, large-grit, acid-etched (SLA) surface implant, which had a calcium phosphate (CaP) coating applied by ion-beam-assisted deposition (IBAD). We also evaluated the effect of heating the coating to different temperatures. The CaP-coated SLA implants exhibited a slightly larger bone healing capacity in the self-contained coronal defect than SLA implants, indicating that combining SLA surface implants and a CaP coating by the IBAD method had synergistic effects on bone healing. There was no difference in the healing capacity between 350 °C and 450 °C heat treatment of the coating layer.

Production and Test of a REBCO Superconducting Synchronous Motor

We designed and fabricated a 7.5 kW-360 rpm synchronous motor with a superconducting rotor. The rotor was 6-pole type and has no iron core. The armature winding was wound with copper wires. 6 pieces of racetrack-shaped field coils were wound with 5 mm wide RE1Ba2Cu3O7-delta (REBCO, RE:Rare Earth) superconducting tapes produced by an ion beam assisted deposition method and a pulsed laser deposition method. The total length of REBCO tape was 400 m per a field coil. We confirmed the good transport properties of the respective field coils up to 80 A at 40 to 50 K before and also after the assembly to a motor. The maximum magnetic field in the field coils was 0.67 T. The superconducting rotor was cooled down to around 40 K by forced-flowed helium gas and the completed motor was tested in a similar way to conventional motors. As a result of a load test, the designed operation of 7.5 kW at 360 rpm was verified for the rated field current of 60 A. Even when the field current was increased up to 70 A at 40 K, the temperature at each part of the superconducting rotor was held constant and the quite stable operation up to 11 kW at 360 rpm was also achieved.

Significant reduction in volume, stored energy and magnetization loss of high-field magnet coil based on the improvement of critical current characteristics in GdBCO coated conductor

We have characterized current transport properties in a GdBa 2Cu 3O 7−δ coated conductor fabricated by a combination of ion-beam assisted deposition (IBAD) method and pulsed laser deposition (PLD) method with reel-to-reel systems, and have applied them to a coil design for a high-field magnet. The J- E characteristics in the conductor are given as a function of temperature, magnetic field and the field angle based on percolation transition model, and its potential as a high-field magnet coil is discussed based on a finite element method analysis. As a result, we have found that the conductor with I c = 350 A/cm-w at 77 K and self-field has a possibility to realize a 40 T magnet coil with very compact size (300 mm in outside diameter) and small usage of the coated conductor (8 km). Furthermore, we have also investigated the relationship between the scale of the magnet coil and the corresponding requirements for the conductor. Consequently, it has been suggested that the improvement of critical current characteristics of the conductor greatly advances the downsizing of the coil without large increment in hoop tensile force. In addition, it has also been found that such downsizing of the coil contributes to the reduction in stored energy and total magnetization loss of the coil. This means that the recent improvement of critical current characteristics in coated conductors is especially worthwhile for high-field magnet coils in terms not only of downsizing but also of quench protection and magnetizing/demagnetizing operation.

Substrate surface treatment and YSZ buffer layers by IBAD method for coated conductors

In this work, an Ion Beam Assisted Deposition (IBAD) system was utilized to fabricate Yttria-Stabilized Zirconia (YSZ) template films for coated conductors. The surface of the Hastelloy C276 substrate was modified by rolling and electropolishing. The effect of the electropolishing parameters of the substrate on the texture of the YSZ buffer layers was studied. The electropolishing current and time were optimized for short samples of 1 cm×1 cm square shape as 1 A and 60 s, respectively. And the relationship between the roughness of the substrate surface and the texture of the YSZ layer is discussed. Reel-to-reel metal tape moving apparatus was installed and used to produce meter-long buffer layer for coated conductors. The YSZ template film was deposited by IBAD method on meter-long Hastelloy tape with tape shifting speed of 15–20 m/h, and the thickness of the buffer layer was up to about 1.7 μm. The Hastelloy substrate surface was measured by Atomic Force Microscope. The thickness of the YSZ films over length was measured by Thermal Field Emission Scan Electronic Microscopy. X Ray Diffraction Ω-scan and ϕ-scan measurements were performed in order to examine the out-of-plane and in-plane texture of the YSZ buffer layers, respectively.