Physical Vapor Deposition Method Research Articles

Biological and Electrochemical Behaviour of Zirconia Modified 316L SS for Potential Biomedical Applications

Abstract Numerous metallic implant materials have been used to replace various damaged or missed part of the body due to its strength, wear resistance and moderate corrosion resistant properties. However, the ideal implant characteristics such as bioactivity, hemocompatibility, corrosion resistance, mechanical strength, antimicrobial activity, etc are not usually achieved in single metallic implant materials. Hence, the surface tailored ceramics coating onto metallic materials will be a suitable choice to obtain the above ideal biomaterials characteristic properties in a single system. Different phases of zirconia ( m -ZrO 2 , t -ZrO 2 and c -ZrO 2 ) were deposited onto 316L SS substrate by electron beam physical vapor deposition (EBPVD) method. The microstructure and surface topography was analyzed by X-ray diffraction and atomic force microscopy (AFM) respectively. Further, bacterial invasion analysis by total viable count (TVC) and the results showed that different ZrO 2 coating effectively protected the bacterial invasion. Hemolysis behavior was studies and it did not express any hemolytic nature against the test samples. Furthermore, electrochemical behavior of the samples was examined in presence of goat whole blood as electrolyte solution. The EIS results divulged that the coated materials ( m -ZrO 2 , t -ZrO 2 and c -ZrO 2 ) showed higher corrosion resistance nature than that of bare 316L SS substrate. Hence, the overall result\s reveal that ZrO2 coating with three different phases can be used for potential biomedical applications.

An Investigation on Surface Roughness and Tool Wear in Turning Operation of Inconel 718

This paper investigates the influences of three different input parameters, such as feed rate, insert nose radius, and insert coating methods, in the turning operation of Inconel 718. The coating methods were selected as medium temperature chemical vapor deposition (MT-CVD) and physical vapor deposition (PVD) and in addition to coating methods, the role of various coating materials was discussed since the inserts were coated with multi-layers of TiCN/Al2O3/TiN and single-layer of TiAlN on carbide substrates. The results were discussed in terms of wear behavior of cutting tools and surface quality of the workpiece, which is indicated by surface roughness. A full factorial experimental design was employed in the present work and the results were evaluated using main effects plots. Furthermore, the analysis of variance (ANOVA) method was applied to specify both reactive and non-reactive effects of experimental parameter reactions. The results showed that surface roughness is reduced using low feed rates and large nosed inserts in the operations. Furthermore, TiAlN-coated inserts with PVD method provided better surface finish than with MT-CVD method. It was also found that surface roughness increases as the wear rate of inserts increases.

Friction Behavior of TiAlN, AlTiN and AlCrN Multilayer Coatings at Nanoscale

In this study, 3.5 μm thick TiAlN, AlTiN, and AlCrN multilayer coatings were deposited on the H13 steel surface by physical vapor deposition (PVD) method. Friction behavior of these coatings was investigated by friction force microscopy for the first time at nanoscale in the literature. Friction force measurements were performed with the atomic force microscopy lateral force mode at various loads. Results showed that the AlTiN coating had three times lower COF value than the TiAlN and AlCrN coatings due to the lower surface energy. It was observed in this study that Amonton’s law was valid for the COF evolution at the nanoscale.

Physical synthesis of iron oxide nanoparticles and their biological activity in vivo

The physical synthesis of iron oxide nanoparticles obtained from the vapor phase using the electron beam physical vapor deposition method is considered. The results of studying the structure of porous condensates of iron—sodium chloride compound, chemical and phase compositions, as well as nanoparticles size are presented. With a rapid removal from vacuum, iron nanoparticles are oxidized in the air to magnetite. In the initial state, they have significant sorption capacity with respect to oxygen and moisture, therefore, with further heating in the air, the porous condensate mass decreases up to the temperature 650 °C, primarily due to the desorption of physically sorbed moisture. Physically adsorbed oxygen participates in oxidation of Fe3O4–Fe2O3 in the range of 380–650 °C. An increase in condensation temperature is accompanied by an increase of nanoparticle size, as a result of which the total surface area of nanoparticles is significantly reduced, and, consequently, their sorption capacity is decreased. Even without stabilization, such nanoparticles studied as ex tempore prepared aqueous dispersion have characteristic anti-anemic effect in the laboratory animals that can be used in medicine.

Enhancement of the Mechanical and Tribological Performance of Stainless Steel 304 by Ti-Based Nanocomposite Coatings Deposited by PVD Method

The Ti-based nanocomposite coatings such as Ti-Si-B-C and Ti-Si-B-C-N were developed through physical vapour deposition (PVD) i.e. sputtering method on stainless steel (SS 304). The film was deposited under argon and nitrogen atmosphere for development of Ti-Si-B-C and Ti-Si-B-C-N thin films respectively. The performance of mechanical behaviour such as the hardness and modulus were investigated by using nanoindenter XP. The results exhibited that both hardness and modulus of SS 304 were enhanced by Ti-Si-B-C and Ti-Si-B-C-N films. The ball-on-disc tribometer was conducted for comparative wear study of the films as well as uncoated SS 304 substrate at load 50gm. The wear loss and friction coefficient of the samples revealed the superior wear resistance behaviour of Ti-Si-B-C and Ti-Si-B-C-N films. The 3D topographies and 2D cross sectional profiles of the worn surface were studied by 3D profilometer. The roughness of the coated and uncoated surface was measured by using AFM, which suggested that lower deposition rate enabled to prepare smoother surface. The microstructural and compositional feature of the surfaces was carried out with the assistance of FESEM and EDX respectively.

Optical characterization of nanostructured Ge1 − xSnxSe2.5 (x = 0, 0.3, 0.5) films

The paper reports the optical properties of thin films of nanostructured Ge1 − xSnxSe2.5 (x = 0, 0.3, 0.5) glassy alloys. The glassy alloys of Ge1 − xSnxSe2.5 (x = 0, 0.3, 0.5) were prepared using melt quenching method. Thin films of nanostructured Ge1 − xSnxSe2.5 (x = 0, 0.3, 0.5) glassy alloys were prepared using physical vapor deposition method. The films were characterized using XRD, EDX and TEM, which confirmed the amorphous nature, composition and formation of nanorods in the samples. Absorption and transmission spectra of thin films were recorded in the spectral range 400–2500 nm to obtain energy band gap, refractive index, extinction coefficient, dielectric constant etc. Results show that refractive index increases while band gap decreases on increase of Sn content in the Ge–Se system. This is due to the increase in density of defect states within band gap. The values of Urbach energy support the obtained results.

The Remote Light Emission Modulated by Local Surface Plasmon Resonance for the CdSe NW–Au NP Hybrid Structure

AbstractCdSe nanowire (NW)–Au nanoparticle (NP) compounds are synthesized successfully using the method of physical vapor deposition, and the modulated remote emission is realized in the hybrid structure with strong metal–semiconductor coupling. The well‐crystallized, uniform morphology, smooth surface CdSe NW is attached with an Au NP on the terminal, which forms the integration structure with direct plasmon–exciton coupling of semiconductor–metal hybrid system. When the CdSe terminal or Au NP terminal of the hybrid structure is excited by the laser with wavelength of 633 nm, the remote light emission at another terminal is greatly modulated. To reveal the physical mechanism of energy conviction between plasmon and exciton, finite‐difference time‐domain simulations are performed for the CdSe NW–Au NP hybrid structures. The calculated results confirm that the modulation of remote light emission is attributed to the competing of the quench of photoluminescence and the electric field enhancement of local surface plasmon resonance. These works can provide deeper understanding of physical mechanism of plasmon and exciton coupling, and open up new application for the remote light sensing and detection.

Wear Evaluation of Engine Piston Rings Coated With Dual Layer Hard and Soft Coatings

The main objective of this investigation is the evaluation of the performance of hard diamond-like-carbon (DLC) or tungsten carbide (WC) and soft (epoxy composite) dual-coatings on the internal combustion (IC) engine piston rings as a protective coating to reduce their wear. The rings were coated with DLC or WC by physical vapor deposition (PVD) method and then soft polymeric composite coating (epoxy/graphene/base oil SN150) was applied on the hard coating. The tribological tests of the dual-coated piston rings were conducted for 3.6 × 105 cycles at 1500 rpm engine speed and 50% rated load of a diesel engine in order to evaluate the wear performance of the piston rings. Scuffing of cylinder liner and piston rings interface was prevented by the application of polymer composites over the hard-coated rings. DLC hard and soft polymer composite dual coating over the top piston ring was found to have the lowest wear rate 1.69 × 10−12 mm3/N·m compared with the wear rate of dual coatings on the middle and lower rings.

Enhanced thermal conductivity of MoS2/InSe-nanoparticles/MoS2 hybrid sandwich structure

MoS2 based hybrid structures have much attention due to their novel structures and potential applications in diverse areas, such as solar energy conversion, thermoelectric power generation and photo-transistors. In the present work, we have fabricated a novel sandwich structure of MoS2/InSe-nanoparticles (NPs)/MoS2 layers on SiO2/Si substrate by a combination of chemical vapor deposition and physical vapor deposition methods. The morphology of these structures was also studied using scanning electron microscopy. In addition, we have also explored the thermal properties of these hybrid sandwich structures using temperature and power-dependent Raman spectroscopy. For MoS2/InSe-NPs/MoS2 sample, the first-order temperature coefficients of E12g and A1g modes were found to be −0.01722 and −0.01575 cm−1/K, respectively, which are significantly large compared to MoS2 layers without InSe-NPs (i.e. MoS2/MoS2 sample). Further, the thermal conductivity of MoS2/InSe-NPs/MoS2 and MoS2/MoS2 samples on SiO2/Si substrate was extracted as ∼102.3 and ∼81.7 W/m-K, respectively. This work suggests an effective way to form a novel 2D-MoS2 based sandwich structure with semiconductor/metal-NPs; opening up a new scenario to understand the electronic structure of the hybrid structure, and the local strain introduced by NPs. Electron-phonon interactions at an interface can have significant effects on electrical/thermal transport through the optoelectronic devices.

Production of nanopowders from physical vapor deposited films on nonmetallic substrates by conjunctional freezing-assisted ultrasonic extraction method

A new technique to extract nanoscale powders from thin films deposited by a physical vapor deposition method on nonmetallic substrates is proposed. Powders were extracted from films of different materials, such as silicon, nickel, copper, iron, aluminum and cobalt, and compounds, such as aluminum nitride, aluminum oxide, copper oxide, iron oxide, nickel cobaltite, nickel ferrite, nickel oxide, silicon carbide, silicon nitride and silicon oxide. These thin films were deposited on glass substrates by magnetron sputtering, pulsed-laser deposition, spray pyrolysis or thermal evaporation, and the particle sizes of the extracted powders were comparable to those of film samples. This technique is fast, low cost, reliable, highly clean and appropriate for large-scale samples.

Tribological Behavior of TiAlN, AlTiN, and AlCrN Coatings at Boundary Lubricating Condition

In this study, ~ 3.5 µm thick multilayer titanium alumina nitride (TiAlN), alumina titanium nitride (AlTiN), and alumina chromium nitride (AlCrN) coatings were deposited on the H13 steel surface by cathodic arc physical vapor deposition (CAPVD) method. The tribological performance of the coatings was evaluated by a tribometer at boundary lubrication condition. Then, coating surfaces were observed by optical microscope, optical profilometer, and atomic force microscope to evaluate the morphological changes, wear volumes, and tribofilm thickness. Also, scanning electron microscopy (energy dispersive X-ray) and X-ray photoelectron spectrometry analyses were applied to coating surfaces for the tribochemical evolution of the tribofilm. Results showed that AlCrN coating performed the best tribological behavior at boundary lubricated condition, when compared to TiAlN and AlTiN coatings and it can be used as a wear resistant cam tappet coating in internal combustion engines.

Critical Atomic-level Processing Technologies: Remote Plasma-enhanced Atomic Layer Deposition and Atomic Layer Etching

As feature sizes of devices shrink every year, deposition and etching processes change to be very challenge, especially for sub-7 nm technology node. The acceptable variability of feature size is expected to be several atoms of silicon/germanium in the future. Therefore, Remote Plasma-Enhanced Atomic Layer Deposition (RPE-ALD) and Atomic Layer Etching (ALE) change to be more and more important in the semiconductor fabrication. Due to their self-limiting behavior, the atomic-scale fidelity could be realized for both of them in the processes. Compared with traditional Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) methods, atomic-scale thickness controllability and good conformality can be achieved by RPE-ALD. Unlike conventional plasma etching, atomicscale precision and excellent depth uniformity can be achieved by ALE. The fundamentals and applications of RPE-ALD and ALE have been discussed in this paper. Using the combination of them, atomic-level deposition/etch-back method is also mentioned for achieving high quality ultra-thin films on three dimensional (3D) features.

A STM study of Ni-Rh bimetallic particles on reducible CeO2(111)

Ni-Rh particles were prepared on well-ordered CeOx(111) thin films by physical vapor deposition method under ultrahigh vacuum conditions. CeOx(111) (1.5 < x < 2) thin films with controlled oxidation states were grown on Ru(0001) to examine the effect of support structures on the growth and sintering of Ni-Rh particles. Scanning tunneling microscopy studies reveal that pure Ni and Rh grow small particles with 0.3 ML coverage at room temperature on CeO2(111), suggesting a strong metal-ceria interaction. Smaller metal particles are formed on a reduced CeO1.75(111) surface. The degree of Ce reduction in ceria can also affect the electronic properties of deposited metals. Charge transfer from the metal to ceria was observed upon deposition of both Rh and Ni on CeO2. However, Ni and Rh remain a metallic state on CeO1.75. Bimetallic Ni-Rh particles were prepared by deposition of 0.3 ML Rh followed by 0.3 ML Ni on CeO2 at 300 K. A large fraction of Ni deposits on the pre-dosed Rh particles on CeO2 to produce bimetallic Ni-Rh particles. However, a significant amount Ni was observed to form additional pure Ni particles. The formation of Ni-Rh bimetallic particles can be promoted by increasing the particle density upon deposition of the first metal, which can act as the nucleation sites for the second metal. Ni-Rh bimetallic particles exhibit a significantly smaller size compared to that of pure Ni and Rh upon heating. Addition of Rh can inhibit the sintering of Ni and enhance its thermal stability on ceria. Our study has provided morphological and size information for the understanding of the activity of ceria-supported Ni-Rh catalysts.

Highly crystalline synthesis of tellurene sheets on two-dimensional surfaces: Control over helical chain direction of tellurene

Recent results have identified two-dimensional (2D) tellurene as a potential van der Waals (vdW) material for thermoelectric and optoelectronics applications owing to their pseudo-one-dimensional (anisotropic) behavior and structure. While hydrothermal synthesis is suitable for yielding potentially crystalline materials, it is well known for its incompatibility with manufacturing and scaling. There is an urgent need for synthesis of tellurene sheets in vdW layered form with the desired crystallinity as well as controlled crystalline anisotropy using more conventional and scalable processes. Here, we report on the synthesis of tellurene sheets onto a variety of surfaces of vdW-bonded 2D layered crystals in their trigonal layered form with controlled tellurene chain (anisotropy) direction using horizontal physical vapor deposition method. Our systematic tellurene growth studies on six different vdW surfaces show that GaS and GaSe surfaces enable highly crystalline and self-oriented tellurene sheets. Detailed cross-sectional transmission electron microscopy (TEM), angle-resolved Raman spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy measurements provide fundamental insights into the growth dynamics and characteristics of tellurene. First-principles calculations and cross-sectional TEM measurements suggest that tellurene chains are well-oriented along the GaSe armchair lattice direction owing to the much-reduced total energy of the system and a stronger degree of coupling across adjacent layers. Synthesized tellurene sheets exhibit remarkable structural anisotropy, as evidenced by angle-resolved Raman measurements, and the overall results open a clear pathway for layer-by-layer growth of tellurene sheets with controlled crystalline anisotropy using conventional synthesis techniques.

The formation and characterization of titanium dioxide layers deposited on copper middle nano-layer

In this research, two thin layers of Cu with thicknesses of 20 ± 2 nm and 30 ± 2 nm are coated on substrates of quartz. A layer of titanium dioxide with a thickness of 300 ± 25 nm is coated on each nano layer. Also, in order to compare, a layer of titanium dioxide with a thickness of 300 ± 25 nm is coated on a substrate of quartz. All coatings are conducted using physical vapor deposition and electron beam deposition methods. The major goal is to study the impact of Cu nano layer on the surface morphology, grain size, grain boundaries, crystalline structure and phases, and some optical properties such as absorption and transmission of titanium dioxide layers. The field emission scanning electron microscope is used to analyze the surface morphology. Moreover, the crystalline structure of layers is determined using X-ray diffraction. The transmission and absorption of titanium dioxide layers are also determined using ultraviolet–visible spectroscopy. These analyses indicate that the existence of a middle nano layer of copper makes the layers’ surfaces denser and more uniform; however, it has no effect on the structure of layers’ crystalline phase and the way of transferring the layers’ crystalline phase caused by annealing. A slight increase in layers’ absorption and a small shift in absorption edge occur due to the presence of middle nano layer of copper and its thickening. Another remarkable effect that happens due to the presence of copper’s middle nano layer is the amplification and shift of absorption bands in the visible spectrum.

Growth and thermal properties of various In2Se3 nanostructures prepared by single step PVD technique

In2Se3 nanostructures have attracted much attention due to their potential applications in diverse areas, such as solar energy conversion, thermoelectric power generation, phase change random access memories, photodetectors, and optoelectronics in the visible region. In the present work, we have fabricated various In2Se3 nanostructures on SiO2/Si substrate using a simple and single-step physical vapor deposition (PVD) method, without using metal seed layer on the substrates. Morphology, structure and phase of the as-grown In2Se3 nanostructures have been carried out using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, respectively. In addition, we have also explored thermal properties of In2Se3 nanostructures on SiO2/Si substrate using temperature and power dependent Raman spectroscopy. Further, the thermal conductivity of nanoparticles, nanospheres, and rod like flowers at room temperature were found to be ∼37.6, ∼39.5, and ∼15.6 W/m-K, respectively. This work suggests an effective way to form various novel nanostructures, opening up a new scenario to understand the vibrational properties and electron-phonon interactions of In2Se3 nanostructures.

Highly Improved Switching Properties in Flexible Aluminum Oxide Resistive Memories Based on a Multilayer Device Structure

AbstractMultilayer aluminum oxide (Al2O3) resistive memory devices, exhibiting robust switching properties fabricated on a flexible polyethylene naphthalate substrate using only physical vapor deposition methods at room temperature, are reported here. Improved reliability and robust switching properties of the multilayer Al2O3 memory devices are observed compared to those of the single‐layer devices, with the assistance of a guide filament formed in the bottom Al2O3 resistive layer. The multilayer Al2O3 resistive memory devices exhibit nonvolatile and bipolar resistive switching properties with high ON/OFF ratio (&gt;104), DC sweep endurance cycles (&gt;700), statistical uniformity, and retention times (2 × 104 s). The role of the guide filament in the multilayer structure is identified in the non‐rewritable properties of the bottom layer device, increased reset current values, and spatial temperature distribution simulation. Thus, the formation sites of the switchable filament in the top Al2O3 layer can be specified by the guide filament, resulting in remarkable improvement of reproducibility with more robust metallic percolation paths. The reliable resistive switching properties in flexible conditions is also evaluated in a bent radius of 10 mm, and the suggested flexible multilayer memory devices can provide promising strategies to be utilized in future practical storage media.

Wetting Layer and Formation of Metal - Semiconductor Interface

A wetting layer with a nanophase structure was detected and identified before the first bulk phase during the formation of the metal-silicon interface by vapor-phase deposition at room temperature of the substrate. This became possible due to the developed technique for complex analysis of the structural-chemical state of the surface/ interface with help of Auger electron spectroscopy and electron energy loss spectroscopy, and also due to the method of physical vapor deposition at low temperature of vapor. The discovery this wetting layer and stage of its formation fundamentally changes the approach to the formation of contact between metal and silicon.

Protective Properties of a Microstructure Composed of Barrier Nanostructured Organics and SiOx Layers Deposited on a Polymer Matrix.

The SiOx barrier nanocoatings have been prepared on selected polymer matrices to increase their resistance against permeation of toxic substances. The aim has been to find out whether the method of vacuum plasma deposition of SiOx barrier nanocoatings on a polyethylene terephthalate (PET) foil used by Aluminium Company of Canada (ALCAN) company (ALCAN Packaging Kreuzlingen AG (SA/Ltd., Kreuzlingen, Switzerland) within the production of CERAMIS® packaging materials with barrier properties can also be used to increase the resistance of foils from other polymers against the permeation of organic solvents and other toxic liquids. The scanning electron microscopy (SEM) microstructure of SiOx nanocoatings prepared by thermal deposition from SiO in vacuum by the Plasma Assisted Physical Vapour Deposition (PA-PVD) method or vacuum deposition of hexamethyldisiloxane (HMDSO) by the Plasma-enhanced chemical vapour deposition (PECVD) method have been studied. The microstructure and behavior of samples when exposed to a liquid test substance in relation to the barrier properties is described.

Optimization of Solid Particle Erosion by ZrN Coating Applied Fiber Reinforced Composites by Taguchi Method

In this study, ZrN coatings are applied on glass and carbon fiber reinforced epoxy composite materials by magnetron sputtering method to gain an improved understanding of the solid particle erosion (SPE) wear resistance. The tests were carried out by selecting two different impact velocities (34, 53 m/s), four different impingement angles (30°, 45°, 60°, 90°) and two different abrasive (SiO2) particle sizes (approximate 250, 500 m). The thickness of ZrN coating material was 0.15 m. Protective coatings produced by using Physical Vapor Deposition (PVD) method can increase the life time of the components. All test specimens regardless of their various parameter properties exhibit maximum erosion rates at 45 impingement angle and thus exhibiting similar behavior as that observed for semi ductile materials. Optic microscopic views were performed on the surfaces in order to characterize the erosion mechanism. The erodent particles of the both coating layer and composite matrix were found of main role in governing the wear progression. The measured erosion rates were sensitively correlated with the material removal process in order to explain the changes within the coated interfaces. Moreover, an erosion test facility at room temperature and Taguchi’s orthogonal arrays were used for experimentation. The expression derived from the results of Taguchi experimental design is proposed as a predictive equation for estimation of erosion rate of these composites. It is demonstrated that the predicted results from this equation are consistent with the experimental observations. Finally, an optimal parameter combination was determined, which led to minimization of erosion rate (ER).