Substrate Bias Voltage Research Articles

Improvement of the Wear and Corrosion Resistance of CrSiN Films on ZE52 Magnesium Alloy Through the DC Magnetron Sputtering Process

The utilization of magnesium alloys as lightweight structural materials is becoming increasingly prevalent, particularly within the fields of electronics, automotive engineering, and defense. These alloys display high specific strength and excellent heat dissipation properties. The magnesium–zinc–rare earth alloy ZE52 displays superior formability and strength-ductility when compared to conventional magnesium alloys. A CrSiN film was deposited on the surface using a sputtering technique with the objective of enhancing wear and corrosion resistance for industrial applications. A CrSi buffer layer was deposited onto the ZE52 substrate prior to the deposition of the CrSiN film, with the objective of enhancing the adhesion between the two materials. The sputtering process for CrSiN films entailed the modulation of the substrate bias voltage. The CrSiN films exhibited a nanocomposite structure comprising CrN nanocrystallites embedded within an amorphous Si3N4, which resulted in enhanced hardness. Upon adjusting the bias voltage, improvements in mechanical properties were observed, with the film hardness and Young’s modulus increasing to 16.5 GPa and 187.4 GPa, respectively. Among the various CrSiN coatings under investigation, the ZE52 alloy that was coated with a CrSiN film deposited at a bias voltage of −50 V and a substrate temperature of 250 °C demonstrated the most favorable performance, exhibiting the lowest wear rate and superior corrosion resistance. In the tungsten carbide wear test with a loading of 4 N, the coating exhibited the lowest wear rate, at 2.2 × 10−6 mm3·m−1·N−1. Furthermore, the coating demonstrated remarkable corrosion resistance in a 3.5% NaCl solution, displaying a corrosion current density of 1.23 μA·cm−2 and a polarization resistance of 1271.4 Ω·cm−2.

Combinatorial Deposition and Wear Testing of HiPIMS W-C Films

We used high-power impulse magnetron sputtering (HiPIMS) to deposit tungsten carbide films for superior wear protection in abrasive environments. In order to sample different W-to-C ratios more efficiently, a combinatorial approach was chosen. A single sputter target with two equal segments was used, consisting of an upper tungsten and lower graphite segment. This allowed us to vertically sample various elemental compositions in just one deposition run without creating graphitic nano-layers by rotating the substrate holder. The substrate bias voltage, being one of the most effective process parameters in physical vapor deposition (PVD), was applied in both constant and pulsed modes (the latter synchronized to the target pulse). A direct comparison of the different modes has not been performed so far for HiPIMS W-C (separated W and C targets). The resulting coating properties were mainly analyzed by nano-hardness testing and X-ray diffraction. In general, the W2C phase prevailed in tungsten-rich coatings with pulsed bias, leading to slightly higher tungsten contents. Hardness reached maximum values of up to 35 GPa in the center region between the two segments, where a mix of W2C and WC1-x phases occurs. With pulsed bias, voltage hardnesses are slightly higher, especially for tungsten-rich films. In those cases, compressive stress was also found to be higher when compared to constant bias. Erosive wear testing by blasting with alumina grit showed that the material removal rate followed basically the coating’s hardness but surprisingly reached minimum wear loss for W2C single-phase films just before maximum hardness. In contrast to previous findings, low friction that requires higher carbon contents of at least 50 at. % is not favorable for this type of wear.

Influence of substrate bias voltage on tribological and corrosion properties of tetrahedral amorphous carbon films

Influence of substrate bias voltage on tribological and corrosion properties of tetrahedral amorphous carbon films

Effect of Bias Voltage on the Microstructure and Photoelectric Properties of W-Doped ZnO Films.

W-doped ZnO (WZO) films were deposited on glass substrates by using RF magnetron sputtering at different substrate bias voltages, and the relationships between microstructure and optical and electrical properties were investigated. The results revealed that the deposition rate of WZO films first decreased from 8.8 to 7.1 nm/min, and then increased to 11.5 nm/min with the increase in bias voltage. After applying a bias voltage to the substrate, the bombardment effect of sputtered ions was enhanced, and the films transformed from a smooth surface into a compact and rough surface. All the films exhibited a hexagonal wurtzite structure with a strong (002) preferred orientation and grew along the c-axis direction. When the bias voltage increased, both the residual stress and lattice parameter of the films gradually increased, and the maximum grain size of 43.4 nm was achieved at -100 V. When the bias voltage was below -300 V, all the films exhibited a high average transmittance of ~90% in the visible light region. As the bias voltage increased, the sheet resistance and resistivity of the films initially decreased and then gradually increased. The highest FOM of 5.8 × 10-4 Ω-1 was achieved at -100 V, possessing the best comprehensive photoelectric properties.

Influence of Substrate Bias Voltage on Structure and Properties of (AlCrMoNiTi)N Films.

(AlCrMoNiTi)N high-entropy alloy nitride (HEAN) films were synthesized at various bias voltages using the co-filter cathodic vacuum arc (co-FCVA) deposition technique. This study systematically investigates the effect of bias voltage on the microstructure and performance of HEAN films. The results indicate that an increase in bias voltage enhances the energy of ions while concomitantly reducing the deposition rate. All synthesized (AlCrMoNiTi)N HEAN films demonstrated the composite structure composed of FCC phase and metallic Ni. The hardness of the (AlCrMoNiTi)N HEAN film synthesized at a bias voltage of -100 V attained a maximum value of 38.7 GPa. This high hardness is primarily attributed to the synergistic effects stemming from the formation of strong metal-nitrogen (Me-N) bonding formed between the target elements and the N element, the densification of the film structure, and the ion beam-assisted bombardment strengthening of the co-FCVA deposition technique. In addition, the corrosion current density of the film prepared at this bias voltage was measured at 4.9 × 10-7 A·cm-2, significantly lower than that of 304 stainless steel, indicating excellent corrosion resistance.

The effect of substrate bias voltage on the properties of Al-doped ZnO films deposited by magnetron sputtering

Our work aims to investigate the influence of substrate bias voltage on the structure, optical, and electrical properties of ZnO:Al thin films deposited on Si (100) and glass substrates by radio frequency magnetron sputtering. We have applied the layer-by-layer growth method in magnetron sputtering. X-ray diffraction, atomic force microscopy, Raman scattering, photoluminescence, Fourier transform infrared spectrometry, multi-angle spectral ellipsometry, optical transmission, and electrical measurements were used to characterize samples. It was found that the negative bias voltage applied to the substrate holder during film growth caused an increase in the conductivity of ZnO:Al films four times compared with ZnO:Al films grown without external bias voltage. The concentration of Al donor impurity was increased in ZnO:Al films with increasing the negative bias voltage applied to the substrate.

Synthesis of AlxCoCrFeNi HEA thin films by high power impulse magnetron sputtering: Effect of substrate bias voltage

Synthesis of AlxCoCrFeNi HEA thin films by high power impulse magnetron sputtering: Effect of substrate bias voltage

Design and Scalable Synthesis of Thermochromic VO2-Based Coatings for Energy-Saving Smart Windows with Exceptional Optical Performance.

We report strongly thermochromic YSZ/V0.855W0.018Sr0.127O2/SiO2 coatings, where YSZ is Y-stabilized ZrO2, prepared by using a scalable deposition technique on standard glass at a low substrate temperature of 320 °C and without any substrate bias voltage. The coatings exhibit a transition temperature of 22 °C with an integral luminous transmittance of 63.7% (low-temperature state) and 60.7% (high-temperature state) and a modulation of the solar energy transmittance of 11.2%. Such a combination of properties, together with the low deposition temperature, fulfills the requirements for large-scale implementation on building glass and has not been reported yet. Reactive high-power impulse magnetron sputtering with a pulsed O2 flow feedback control allows us to prepare crystalline W and Sr codoped VO2 of the correct stoichiometry. The W doping of VO2 decreases the transition temperature, while the Sr doping of VO2 increases the luminous transmittance significantly. A coating design utilizing second-order interference in two antireflection layers is used to maximize both the integral luminous transmittance and the modulation of the solar energy transmittance. A compact crystalline structure of the bottom YSZ antireflection layer further improves the VO2 crystallinity, while the top SiO2 antireflection layer provides also the mechanical and environmental protection for the V0.855W0.018Sr0.127O2 layer.

Advancements in biomedical coatings: A comprehensive review of DC magnetron sputtering on Ti–6Al–4V alloy

This study investigates the application of DC magnetron sputtering (MS) technology for producing TiN and ion-substituted Ca-P coatings on dental implant materials, demonstrating ultimate tensile strength (UTS) of 887 MPa, a modulus of elasticity of 11.3 × 106 MPa. The influence of various physical vapor deposition (PVD-MS) parameters—such as substrate temperature, post-heat treatment, deposition duration, discharge power, and bias voltage—on the characteristics of these coatings is examined. The research evaluates the advantages and limitations of PVD-MS in fabricating TiN and Ca-P coatings, with an emphasis on their impact on surface topography and chemical composition, which are critical factors influencing cellular behavior. The study reveals that while ion-substituted HA coatings can enhance cell adhesion, they may also exhibit cytotoxic effects, potentially limiting cell growth. It compares osteogenic cell proliferation rates between low-crystalline HA coatings and highly crystalline variants on Ti-based substrates, highlighting significant performance disparities. Additionally, PVD-MS demonstrates robust adhesion capabilities and facilitates the incorporation of therapeutic ions, effectively replicating bioapatite properties. The addition of coating on the substrate promotes additional strengthening mechanisms of the layers, leading to improved wear resistance compared to an alloyed substrate. Estimated values for hardness range between 7.2 and 8.4 GPa, and for Young's modulus, they range from 126 to 162 GPa. The study highlights the potential of PVD-MS in creating nanostructured Ca-P coatings on biodegradable metals, alloys, and polymeric biomaterials. This technology improves corrosion resistance, biocompatibility, chemical stability, wear resistance, and overall performance in various biomedical applications.

Enhancement of copper nanoparticle yield in magnetron sputter inert gas condensation by applying substrate bias voltage and its influence on thin film morphology

Large-scale synthesis of high-purity nanoparticles is an intense topic of scientific research, with magnetron sputter inert gas condensation recognized as a promising, environmentally friendly technique avoiding wet chemical processes. This study explores the deposition of size-selected nanoparticles under varied substrate bias voltages and reports on a consequent increase in deposition rates up to 32 %. These alterations in substrate bias voltage induce a progressive change in the morphology of the resulting nanoparticle thin films, attributable to the increased kinetic energy of the nanoparticles. Comprehensive characterization via quadrupole mass spectroscopy of the nanoparticle flux, scanning electron microscopy, X-ray photoelectron spectroscopy, and low-energy ion scattering spectroscopy of the deposited nanoparticles corroborates the enhanced nanoparticle yield associated with increased substrate bias voltage. These findings signify a methodological advancement, enhancing the efficiency of magnetron sputter inert gas condensation and moving the technology a step further towards feasible industrial production.

Effects of substrate temperature and bias voltage on mechanical and tribological properties of cosputtered (TiZrHfTa)Nx films

This study investigated the effects of substrate temperature and bias voltage on the mechanical and tribological properties of cosputtered (TiZrHfTa)Nx films. A substrate temperature ranging from room temperature to 400 °C, and a bias voltage ranging from 0 to −150 V were selected as the sputtering variables. A mixture gas with a nitrogen flow ratio (fN2 = N2/[N2 + Ar]) of 0.2 was used to fabricate nitride films. Nanoindentation and wear tests were conducted to assess the performance of the fabricated (TiZrHfTa)Nx films, which formed a single face-centered cubic structure. Increasing the substrate temperature resulted in grain growth, lattice shrinkage, and nonsignificant improvements in mechanical properties. Applying a bias voltage of −150 V to the substrate increased the hardness of the fabricated film to a peak of 32.7 GPa compared with that of 29.3 GPa for the film prepared in an electronically grounded state. The (Ti0.24Zr0.22Hf0.19Ta0.35)N0.66 film prepared at a bias voltage of 0 V and substrate temperature of 400 °C exhibited the optimal combination of mechanical and tribological properties (hardness, 30.0 GPa; elastic modulus, 325 GPa; and wear rate, 1.16 × 10−5 mm3/Nm).

Quantitative characterization on influence of surface particles on corrosion behavior of multiarc ion plated CrAlN coatings

Surface particles on multiarc ion plated coatings are common defects, and their influence on the service performance of coatings is rarely defined. The CrAlN coatings were deposited on the tungsten steel (YG8) substrates using multiarc ion plating. The effects of the substrate bias voltages and nitrogen flow rates on the quantity of the surface particles were investigated, and the influence of the surface particles on the corrosion resistance of the coatings is quantitatively characterized. The morphology of surface particles was characterized using a scanning electron microscope. The quantity of the surface particles was counted by image software. The corrosion resistance of the coatings was evaluated through an electrochemical workstation. The results show that the quantity of surface particles decreased with the increase in the substrate bias voltage and nitrogen flow rate. The corrosion resistance of the coatings showed a positive correlation with the quantity of the surface particles, and it decreased dramatically when the quantity of the surface particles exceeded 111/10 000 μm2. The corrosion mechanism of the coatings was attributed to the defect-induced pitting corrosion.

Fracture strain improving via structural austenitic stainless steel-coated 22MnB5 plates

A total of 316 austenitic stainless steel (ASS) coatings were deposited on 22MnB5 press-hardening steel plates by varying the substrate bias voltages using a magnetron sputtering technique and quenched in a flat mold with cooling water. The substrate bias current and ion-bombardment energy densities increased up to 0.5 mA/mm2 and 50 J/mm2 at a high voltage of −100 V, and, therefore, the variations in the coatings’ morphologies were owing to the increases in the ion bombardment. The porous bulk pattern appeared in the quenched ASS coating at −100 V, clearly different from the porous columnar structure of the others at −50 and −75 V. The γ-Fe and α-Fe phases were observed from the diffraction peaks, presented the ASS coating and 22MnB5 substrate, respectively. There was no intermetallic compound (IMC) peak detected. In addition, the diffusion layer of the quenched ASS-coated plate was observed, in which its morphology was different from the quenched martensite (M) plate, and proved to be the α-Fe microstructure by the very low α-Fe peak at the standard (110) position. The bright image of TEM and the select area electron diffraction pattern indicated the nanostructure of the quenched ASS coating. The nanohardness of the ASS coating, diffusion layer, and M plate (7.36, 3.60, and 6.25 GPa, respectively) was detected, indirectly proving an α-Fe structure of the diffusion layer. The fracture angles of the 316-coated plates significantly improved from 51.82° at −50 V, 53.77° at −75 V to 57.38° at −100 V, as the ASS structure changed to be porous bulk pattern. The clearance of IMC, coating’s porous bulk pattern, and the low hardness α-Fe diffusion layer benefited for the fracture strain by lengthening the pathway of the crack’s development and blocking the further crack’s propagation, respectively.

Photodetector Devices: Investigation of ZnO Thin Films Fabricated via SILAR Technique on Various Substrates:

The synthesis of photodetectors for ZnO nanostructure films on various substrates, including p-type (100) silicon (Si), and porous silicon (pSi), has been achieved through the utilization of a straightforward technique known as the successive ionic layer adsorption and reaction (SILAR) method. To analyze the optical properties, surface morphology, and crystal structure of the ZnO layers, UV-Vis spectrometers, field emission scanning electron microscopes (FESEM), and X-ray diffraction (XRD) were employed. The characterization of the ZnO samples revealed that the number of SILAR cycles has a significant impact on the morphology and optical band gap of the synthesized layer. The Fourier-transform infrared (FTIR) spectrum successfully detected the distinctive extended vibration mode of ZnO. By conducting 20 cycles, high-quality hexagonal ZnO was obtained. The responsivity of the planar ZnO on silicon (ZnO/Si) and ZnO on the porous silicon (ZnO/pSi) surface exhibited variations depending on the substrate surface and bias voltage. The results indicated that the (ZnO/pSi) heterojunction demonstrated a high response in the visible range (350–850 nm) at a low bias voltage. On the other hand, the (ZnO/Si) photodetector displayed a high sensitivity of 666.66% at a low voltage of 1V in comparison to the (ZnO/pSi) photodetector, which exhibited a sensitivity of 483%.

Optimizing substrate bias voltage to improve mechanical and tribological properties of ductile FeCoNiCu high entropy alloy coatings with FCC structure

Conventional hard coatings are limited in their tribological applications due to their high brittleness. High-entropy alloy (HEA) coatings, which combine high toughness and hardness, represent a new class of tribological coatings with great potential. The microstructure and stress state of HEA coatings can be significantly affected by the deposition parameters of magnetron sputtering, which can regulate their mechanical and tribological properties. In this study, DC magnetron sputtering with varying substrate bias voltages was used to deposit FeCoNiCu HEA coatings with an FCC single phase structure on 316 stainless steel. The microstructure, mechanical, and tribological properties of these coatings were studied in detail. The residual tensile stress of the coatings decreases, while toughness and hardness increase as the bias voltage increases. The coatings exhibited optimal toughness, highest hardness (11.3 GPa), and the lowest wear rate (as low as 6.01 × 10−5 mm3/N·m) when the bias voltage was set to −200 V. The formation of a metal oxide adhesion layer during friction improved the tribological properties of the coatings. This study demonstrates that optimizing the deposition bias voltage is an effective way to improve the mechanical and tribological properties of high-entropy, face-centered cubic alloy coatings, which are intrinsically tough and ductile.

The deposition properties of the tetrahedral amorphous carbon coating on the piston ring at different incident angles and substrate bias voltages: Molecular dynamics simulation

To reduce the friction and wear of the piston ring-cylinder liner system in the internal combustion engine, the tetrahedral amorphous carbon (ta-C) coating is deposited onto the piston ring. The deposition model is established and deposition process is simulated using molecular dynamics simulation. The visualization of simulation results is obtained using open visualization tool. The second nearest-neighbor modified embedded-atom method potential and Tersoff potential are employed to describe the interactions among the atoms and ions. The deposition properties of the ta-C coating at different incident angles and substrate bias voltages are studied. The layer coverage function, interface mixing, surface morphology, radial distribution function, layer density, layer sp3 fraction, and normal stress of the ta-C coating on the piston ring are analyzed. The simulation results show that a ta-C coating on the piston ring with a smooth surface, a dense amorphous structure, a high sp3 fraction, and a uniform mixing area can be obtained. The minimum RMS roughness is 0.539 Å at −150 V, maximum layer density is 3.560 g/cm3 at −1 V, and maximum layer sp3 fraction is 0.972 at 30°. This study provides theoretical support for the selection of experimental parameters.

Effect of arc deposition process on mechanical properties and microstructure of TiAlSiN gradient coatings

In order to successfully prepare a new advanced TiAlSiN gradient coating with Ti content gradually decreased but Al content gradually increased from the cemented carbide substrate to the outermost coating surface by arc ion plating, we deeply investigated the influence mechanisms of two important process parameters. These parameters include substrate bias voltage and arc current, which affect the mechanical properties and microstructure of the gradient coating. The results show that bias voltage and arc current directly affect the particle accumulation effect on the coating surface and the re-sputtering effect caused by high-energy ion bombardment, thus affecting the deposition efficiency of the coating and the formation of defects such as macro-particles and pits on the coating surface. The increase of bias voltage is conducive to the increase of the density of columnar crystals and nanocrystals. While the increase of arc current makes the coating with high Al content transform from columnar crystals to nanocrystals. The hardness and interfacial adhesion of the gradient coatings showed a tendency of firstly increasing and then decreasing with the increase of both bias voltage and arc current. When the bias voltage and arc current are -80 V and 160 A respectively, the coating has the best mechanical properties, its surface hardness reaches 36.94 GPa, and the interfacial adhesion exceeds 120 N. In addition, with the increase of bias voltage and arc current, particles are deposited on the surface of the coating with higher energy, which leads to the preferential orientation transition from (111) to (200) plane. The high hardness of TiAlSiN coating is mainly due to the formation of high Al content of fcc-TiAlN crystals and amorphous Si3N4 in the gradient-coated surface layer. The results have important theoretical and practical significance for developing new high-performance gradient coating tools.

AlCrTaTiZr-based high entropy alloy nitride coatings on stainless steel substrates: Characterization and microscale tension testing

High entropy alloy nitride coatings promise improved mechanical properties and are under current investigation for a range of applications. In this work, we report deposition of high entropy alloy nitride coatings on 316 stainless steel substrates by inductively coupled plasma assisted dc magnetron reactive sputtering of nominally equiatomic AlCrTaTiZr alloy targets. Characterization of coating composition and structure was carried out through X-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, X-ray diffraction, and scanning/transmission electron microscopy. Mechanical testing was conducted through instrumented nanoindentation, interfacial shear loading through micropillar compression, and tension loading of coated microscale tensile bars in a scanning electron microscope. Microscale tension testing offers a potential avenue to assess the limiting shear strength of the coating/substrate interface, as well as the level of cohesion within the coating. The present study indicates that microscale tension tests yield results consistent with macroscale testing, while avoiding the need for multiple macroscale specimens. The present results suggest that cohesion of the high entropy alloy nitride coating and limiting shear strength of the coating/steel interface both increase with increasing substrate bias voltage during deposition, and that these coatings may be more adaptive to increased levels of ion bombardment during deposition without inducing excessive residual stresses.

Advanced film/substrate interface engineering for adhesion improvement employing time- and energy-controlled metal ion irradiation

Pre-deposition substrate etching by metal ion bombardment is an efficient and fast cleaning method that ensures improved chemical and topological substrate surface modification. Here, we study the effects of metal ion mass and kinetic energy on etching of industrially-relevant cemented carbide (WC) substrate as well as on adhesion at the Ti0.50Al0.50N/WC interface. Cr+ or W+ ion fluxes are generated by high-power impulse magnetron sputtering (HiPIMS), while their kinetic energy Ekin is tuned by applying negative substrate bias voltage synchronously with the metal ion-rich portion of the flux. The time evolution of ion fluxes at the substrate plane is studied with energy- and time-resolved ion mass spectrometry. The threshold substrate bias voltage required to initiate substrate etching is in the 900–1000 V range for both Cr+ and W+ fluxes. Moreover, we show that the adhesion strength of Ti0.50Al0.50N coatings correlates with Ekin. For Ekin < 900 eV, Cr or W interlayers are grown and no significant improvement in the adhesion strength is observed. Contrary, for Ekin > 900 eV, effective substrate etching with energetic metal ions significantly improves the adhesion strength: we demonstrate an increase of 76–79 % after etching with metal ions as compared to the untreated substrate.

PECVD technology deposition of high hardness a-C:H films on micro-drill surfaces: Substrate bias voltage effects

The plasma enhanced chemical vapor deposition (PECVD) technique was utilized to produce hydrogenated amorphous carbon (a-C:H) films. The overall structure of the films consists of a Cr/WC transition layer, a WC/a-C:H transition layer, and an a-C:H functional layer. The study investigated the effects of substrate bias voltages (SBVs) of −580 V, −660 V, −740 V, −820 V, and −900 V on the microstructure, mechanical, and tribological properties of a-C:H films. The findings indicate that different SBVs influence the ionic energy during the deposition of a-C:H films, consequently affecting the film growth. In this case, when the SBV is -820 V, C+ with sufficient energy will penetrate beneath the initial layer in the form of shallow injection. Therefore, compared to other experimental groups, the a-C:H films prepared under this condition have the lowest Ra value (0.42 nm), the highest sp3 CC bond content (39.88 %), the maximum hardness (31.6 GPa), the lowest friction coefficient (0.052), and the smallest wear rate (7.48 × 10−8 mm3/(N·m)), demonstrating significantly better mechanical and tribological properties. The a-C:H films, prepared at different SBVs, are deposited on micro-drill surfaces for hole drilling tests. The experimental results indicate that a-C:H films prepared at SBV of −820 V exhibit the satisfactory drilling performance due to the better mechanical and tribological properties. This is evident not only in the minimal surface wear of the film micro-drill after different drilling quantities but also by the satisfactory quality of the corresponding machined holes. The a-C:H film micro-drill prepared at SBV of −820 V exhibited larger process capability index (CPK) values for the machined holes at 500, 1000, and 2000 hole numbers of 5.449, 3.693, and 3.263 respectively. During the 2000th drill on the printed circuit board (PCB) surface, the hole wall roughness (Rz) and nail head values of the machined hole were measured to be 10.6 μm and 1.3, respectively.