Metal Vapor Vacuum Arc Research Articles

Corrosion, mechanical and biological properties of biodegradable WE43 alloy modified by Al ion implantation

A high-energy metal vapor vacuum arc (MEVVA) ion source was used to implant aluminum (Al) ions into the WE43 alloy (Al-WE43) at a dose of 1 × 1016 ions·cm−2, and the structural composition, mechanical properties, corrosion resistance, and biocompatibility of the alloy before and after implantation were systematically studied. The results showed that an Al2O3/Al thin film was formed on the surface of the WE43 alloy after Al ion implantation, and the dense film caused the corrosion current density (Icorr) of the alloy to decrease from 140.2 ± 9.3 to 17.9 ± 6.1 μA⋅cm−2. Nanoindentation experiments revealed that the elastic model (EIT) and nano-hardness (HIT) of the Al-WE43 alloy were significantly improved due to the surface lattice distortion caused by Al ion implantation. A diluted extract of the Al-WE43 alloy showed higher cell activity, anti-hemolysis and anti-coagulation properties than that of the WE43 alloy. In general, the Al-WE43 alloy can be considered as a promising biodegradable metallic material for cardiovascular stent applications.

Microstructural evolution and vibration fatigue properties of 7075-T651 aluminum alloy treated by nitrogen ion implantation

The effects of nitrogen ion implantation on the microstructures and the vibration fatigue properties of the 7075-T651 aluminum alloy were investigated. Nitrogen ions were implanted into 7075-T651 aluminum alloy by metal vapor vacuum arc (MEVVA) at the dose of 3 × 1017 ions/cm2 at room temperature. The trajectory distribution range and the introduced defects of nitrogen ion-implanted 7075-T651 aluminum alloy were simulated using the Stopping and Range of Ions in Matter software. The phase composition was tested by X-ray diffraction (XRD), the microstructures were characterized using a transmission electron microscope (TEM), and the fracture morphologies of vibration samples were observed using a scanning electron microscope (SEM). Experimental results indicate that the fatigue life of the ion-implanted vibration samples increased by 75% compared with the untreated samples. The ion implantation caused the microscopic strain，which increased the density of dislocation structure and reduced the grain size. The gradient microstructure and fracture properties of the sample were analyzed. The results show that the high-density dislocation and fine grains induced by ion implantation are beneficial to prolong the vibration fatigue life.

ENHANCING UV PROTECTION AND HYDROPHOBIC ABILITIES OF POLYESTER TEXTILES BY NOVEL SURFACE MODIFICATION TECHNIQUES

In this study, water vapour permeability, wrinkle recovery, UV protection and contact angle properties of ion implanted Polyester (PES) fabrics were investigated. In order to achieve this goal; our Metal Vapor Vacuum Arc (MEVVA) source implanted Pb, Ag, Ag+N, Ti+O and Cr+O to the PES fabrics with 5x1016 ion/cm2 and 30 kV acceleration voltage. The test results were compared with unimplanted PES fabric. The results indicated that UV Protection and contact angle values increased significantly and also almost no change observed at water vapour permeability and wrinkle recovery. These results also varied on severly with different ion species.

Beam test of the ion beam facility based on the metal vapor vacuum arc ion source at Korea multi-purpose accelerator complex

Beam test of the ion beam facility based on the metal vapor vacuum arc ion source at Korea multi-purpose accelerator complex

Damage evolution behavior of TiN/Ti multilayer coatings under high-speed impact conditions

The erosion of compressor blades by solid particles brings huge safety hazards to aero engines. The application of erosion-resistant hard coating has become a good solution to protect titanium alloy blades. In this work, TiN monolayer and TiN/Ti multilayer coatings were prepared on Ti-6Al-4V alloy using a magnetic filtered cathode vacuum arc system (FCVA) and a metal vapor vacuum arc (MEVVA) ion implantation device. The mechanical properties of the coatings were evaluated by nanoindentation and scratch tests. The damage evolution behavior and mechanism of TiN monolayer and TiN/Ti multilayer coatings are studied by single-particle impact test and finite element simulation. The results show that the fracture toughness of TiN monolayer coating is lower than that of TiN/Ti multilayer coating; TiN/Ti multilayer coatings exhibit good erosion resistance. The main reason lies in that the Ti layer dissipates part of impact energy by plastic deformation and reduces the tensile stress. The interfaces in the multilayer coating inhibited the propagation of cracks.

Effect of Nitrogen Ion Implantation Energy on the Mechanical and Chemical Properties of AISI M50 Steel

Nitrogen ion implantation has shown its role in enhancing steel surface properties. In this work, AISI M50 steel was implanted with nitrogen ions by using the metal vapor vacuum arc technique with a dose of 2 × 1017 cm−2, and corresponding implanted energies were at 60 keV, 80 keV, and 100 keV, respectively. The distribution of implanted nitrogen ions was calculated, and the samples were tribologically tested and examined. As shown by the results, the microhardness in implanted samples was 1.17 times greater relative to that of the unimplanted sample. The implantation of the nitrogen ion leads to a change in the friction coefficient of the AISI M50 steel. Adhesive wear mechanism occurs in the unimplanted sample, and adhesion resistance tends to increase when nitrogen-implanted energy increases. The formation of oxides α-Fe2O3 and Fe3O4 further enhanced the tribological properties for implanted samples.

Microstructure, Mechanical and Antibacterial Properties of TiNb-Based Alloy Implanted by Silver Ions

In this study, in order to obtain an antibacterial property for the TiNb-based alloy, the metal vapor vacuum arc (MEVVA) ion implantation technology was applied to implant the silver on the surface of TiNb-based alloy, which brought the change of the microstructures and mechanical properties for the surface of substrate. It was found that the diffusely distributed silver nanoparticles generated on the outermost surface of the implanted layer and the Ag element exist as a solid-solution state in the implanted layer. Meanwhile, the region of the implanted layer mainly constituted nanocrystalline structures based on the analyses of microstructures. Hence, the nanocrystalline strengthening effect formed by high-energy ion bombardment and the solid solution strengthening effect of silver atoms made contributions to the increase of surface comprehensive mechanical properties, including the surface hardness and elastic modulus. Finally, the suitable Ag-implanted specimen can obtain excellent antibacterial ability. Except for the antibacterial mechanism of silver ions release, the dispersed silver nanoparticles on the surface also provide the contact antimicrobial mechanism, which is the Schottky barrier–dependent antimicrobial efficacy of silver nanoparticles.

Study on the ZrN/Ag2O Micro–Nano Gradient Composite Structure Constructed on Pure Ti for Biomaterials

Titanium and titanium alloys have been extensively utilized in biomedical implants due to their excellent comprehensive mechanical properties and biocompatibility. In this study, a ZrN/Ag2O micro–nano gradient composite structure was prepared on the surface of pure Ti by multi-arc ion plating (MAIP) technique and metal vapor vacuum arc (MEVVA) ion implantation technology. This study indicated that a dramatic improvement in performance in the surface hardness (~1800 HV0.1) was attributed to the presence of the ceramic phase (ZrN) with high hardness included in composite structure. The relatively low wear rate of gradient composite structure confirmed its excellent performance in abrasion resistance and the abrasion mechanism of gradient composite structure was mainly abrasive wear. After the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests, because of the synergy effect of ZrN micron coating and Ag2O nanoparticles, the ZrN/Ag2O gradient coatings indicated the highest free corrosion potential (Ecorr) and lowest corrosion current density (icorr) in Ringer’s solution, and the polarization resistances of multilayer coatings were greater than that of the substrate, exhibiting positive effects on retarding localized corrosion tendency. Additionally, the suitable dose of ZrN/Ag2O gradient composite coating can obtain antibacterial ability, which exerts no significant cytotoxicity and even excellent cytocompatibility over a longer service process. Furthermore, this study is conducive to design and develop for multifunctional coatings of implant materials.

Exploring the corrosion behavior of Mn-implanted biomedical Mg

Many surface modification technologies have been developed on biomedical magnesium (Mg) and its alloys to expand potential clinical applications. In this study, the bio-safe manganese (Mn) element was implanted into the biomedical Mg surface by a metal vapor vacuum arc (MEVVA) technique. In the Mn-implanted layer, Mn existed in the form of both metallic and oxidized states. Besides, Mn ion implantation changed the corrosion behavior of biomedical Mg in Hank’s solution. At the initial stage of immersion, the corrosion rate was accelerated owing to the galvanic couple between metallic Mn and Mg, and micro-scale galvanic corrosion was uniformly distributed on surfaces. With the immersion time prolonging, Mn-implanted Mg displayed enhanced anti-corrosive property, presenting as a change from corrosion prone to corrosion resistance. On the one hand, the anti-corrosive and uniform Ca, P-containing products were formed on the corroded surface based on uniformly-distributed micro-scale pitting corrosion. On the other hand, the metallic Mn tended to be oxidized to stable Mn oxide so that galvanic corrosion was retarded. This research attempts to explore the effect of Mn ion implantation on the corrosion behavior of biomedical Mg, and offers new insight into novel surface modifications of biomedical Mg devices for long-time implantation.

Analysis of Surface Properties of Ag and Ti Ion-Treated Medical Textiles by Metal Vapor Vacuum Arc Ion Implantation

The study focuses on the effects of Ag (silver) and Ti (titanium) ions on textiles by MEVVA (metal vapor vacuum arc) ion implantation. In order to comprehend this, the research was executed in three parts. In the first part, the antibacterial efficiencies of Ag and TiO2 were investigated in detail since the antibacterial capabilities of Ag and TiO2 are well known. A group of polyester- and cotton-based medical textiles were modified by Ag and TiO2 ions, with doses ranging from 5 × 1015 to 5 × 1016 ion/cm2. To determine the adhesion capabilities of the implanted ions on surfaces, after the first round of antibacterial tests, these medical textiles were washed 30 times, and then antibacterial tests were performed for the second time. The results were also compared with nanoparticle-treated medical textiles. In the second part, the corrosion and friction capabilities of Ag and Ti ion-implanted polyester textiles, with a dose of 5 × 1015 ion/cm2, were investigated. Finally, the UV protection capabilities of Ag and Ti ion-implanted polyester textiles, with a dose of 5 × 1015 ion/cm2, were investigated. The experiments showed that even after 30 washes, the TiO2 ion-implanted polyester textile had almost 85% antibacterial efficiency. In addition, Ti ion implantation reduced the friction coefficiency of a polyester textile by almost 50% when compared with an untreated textile. Finally, the Ag-ion-implanted polyester textile provided a UV protection factor of 30, which is classified as very good protection.

Effect of Yttrium and Rhenium Ion Implantation on the Performance of Nitride Ceramic Cutting Tools.

In the paper, the results of experimental investigations of ion implanted cutting tools performance are presented. The tools, made out of Si3N4 with additives typically used for turning of Ti-6Al-4V alloy, underwent implantation with ions of yttrium (Y+) and rhenium (Re+) using the metal vapor vacuum arc method. Distribution of ions on the tool surface was measured. The cutting tools were tested in turning process with measurement of cutting forces and analysis of wear. A rather unexpected result was the increased wear of the tool after Y+ implantation with 1 × 1017 ion/cm2. It was demonstrated, however, that the tool after Y+ 2 × 1017 ion/cm2 ion implantation provided the best machining performance.

Effect of copper surface modification applied by combined modification of metal vapor vacuum arc ion implantation and laser texturing on anti-frosting property

Heat transfer deterioration due to frost accumulation on metallic surfaces provided motivation for development of protective barriers that could effectively repel water in many forms. Currently, extensive attention has focused on superhydrophobic surfaces which have been found to be effective in reducing droplets condensation and frost accumulation. The combined modification using nanosecond laser and metal vapor vacuum arc (MEVVA) ion implantation of carbon is applied to the copper surface. The results revealed that the increased proportion of carbon content contribute to the increase of surface hydrophobicity, the contact angle of the combined surface was 152.1° ± 1° and the rolling angle was 6.7° ± 1°, which exhibited a superhydrophobic character, without thermal conductivity deterioration. The processes of droplet condensation, freezing and the frosting of three kinds of surfaces (rough #1, combined surface modification #2, silanization coating #3) have been examined. The combined surface can delay the freezing process to some extent. Compared with rough copper surface, combined surface had sparse frost structure and the growth of frost could be delayed by 43% when the frost thickness was 1.5 mm. Thus, the method of combined surface shows a great advantage of frost inhibition applicability.

Mechanical and Tribological Properties of CrN Coated Inconel X750

Three CrN coatings were deposited on the Inconel X750 through the metal vapor vacuum arc ion implantation and the magnetic filtered cathodic vacuum arc deposition system (MEVVA-FCVA) with the N2 flow rates of 10, 50, and 100 sccm, respectively. The surface morphologies and cross-section morphologies of the CrN coatings were obtained through scanning electron microscopy (SEM) and an optical profilometer. The microstructures of the coatings were characterized through X-ray diffraction (XRD). The hardness and the elastic modulus of the coatings were tested by a nano-hardness tester. The adhesion strength and friction coefficients were investigated through scratch tests and ball-on-disk tests and the wear tracks were tested by the optical profilometer. The experimental results indicate that the CrN coating deposited on the Inconel X750 substrate displays a uniform thickness and a smooth surface. The mechanical properties behaves well as the N2 flow rate varies. The CrN coating significantly reduces the friction coefficient fluctuation and improves the antiadhesion and anti-wear properties of the Inconel X750.

MEVVA ion implantation of TiCN coatings; structural and tribological properties

The application of wear resistant metal nitride coatings, typically 2–5 μm thick, is a well-established strategy, employed for prolonging service life of cutting tools, twist drills, taps, dies. Although TiN is an established coating for such applications, in recent years attention has focused on a more diverse range of metal nitride coatings. Specifically, modifications to the TiN structure through the addition of C to produce TiCN are well established for improvement in properties such as friction coefficient and wear rates. Further improvements in tribological performance are expected by modifying the surface using ion implantation.In this exploratory study, TiCN coatings were deposited onto polished AISI 316 stainless steel substrates using commercially available physical vapor deposition technology. Coated samples were ion implanted with a range of metal ions to include Mo, Nb, W, Zr and Cr using the metal vapor vacuum arc (MEVVA) technique. Ions were implanted at a constant dose of 4 × 1016 ions/cm2.The range of techniques used to characterize the implanted layers included x-ray diffraction, Rutherford backscattering, and optical and atomic force microscopy. Dry sliding friction and wear behavior of implanted coatings was assessed using pin on disc equipment.The results showed that, with some exceptions, ion implantation generally improved friction and wear; in particular, implantation with Nb reduced stress levels, grain size, surface roughness, friction and wear rates.

Effects of Zr Ion Implantation on Surface Mechanical Properties and Corrosion Resistance of Pure Magnesium

Zirconium (Zr) was implanted into pure Mg by metal vapor vacuum arc (MEVVA) at the dose of 2 × 1016 ions/cm2 at room temperature. The surface characteristics of Zr-implanted Mg were analyzed by the Stopping and Range of Ions in Matter software (SRIM) and x-ray photoelectron spectroscopy (XPS), the surface nanohardness and tribological behavior were measured through nanoindentation and a friction-abrasion testing machine, and the corrosion resistance of Zr-implanted Mg was evaluated by electrochemical measurement and immersion test in simulated body fluid (SBF). The results demonstrated that a gradient modified layer composed of MgO, Mg(OH)2, ZrO2 and Zr was formed on the near surface of pure Mg and the nanohardness of pure Mg was improved by 48%. Furthermore, the Zr-implanted Mg exhibited a more positive corrosion potential of − 1.43 V (versus SCE) and a lower corrosion current density of 19.9 μA/cm2, and localized corrosion was effectively retarded during 24 h immersion in SBF, suggesting that the corrosion resistance of pure Mg was remarkably improved after Zr ion implantation. The mechanisms of surface strengthening and improved corrosion resistance were also discussed in this paper.

Influence of ion implantation on growth mechanism of α-Fe2O3 nanowires/nanoblades

Hematite nanowires (NWs) and nanoblades (NBs) were successfully synthesized by thermal oxidation at 400 °C and 600 °C, respectively, under atmospheric conditions. Ion implantation was performed using a homemade metal vapor vacuum arc (MEVVA) technique as a new method to interfere with the growth mechanism of NWs/NBs. The metal, rare earth and gas ions with high energies were implanted into the NWs/NBs. The structure and morphology of NWs and NBs were systematically analyzed using different methods such as X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM). The NWs became short and bend, which showed a large deformation and the surface energy changed after Ni/Co/Er/Ar ion implantation. The implanted NWs/NBs were covered entirely by an oxide layer after a short annealing time and new NWs/NBs regrew during a long annealing time. The results were indicated that both the NW and NB formation mechanisms were ascribed to the tip growth model, where the diffusion played a key role. What’ more, the influence of ion implantation on growth mechanism of α-Fe2O3 NWs/NBs was independent of implanted ion species, implanted energy and dose and damage extent decided solely by defects.

Surface Characteristic Effect of Ag/TiO2 Nanoarray Composite Structure on Supercapacitor Electrode Properties.

Ag-ion-modified titanium nanotube (Ag/TiO2-NT) arrays were designed and fabricated as the electrode material of supercapacitors for electrochemical energy storage. TiO2 nanotube (NT) arrays were prepared by electrochemical anodic oxidation and then treated by Ag metal vapor vacuum arc (MEVVA) implantation. The Ag amount was controlled via adjusting ion implantation parameters. The morphology, crystallinity, and electrochemistry properties of as-obtained Ag/TiO2-NT electrodes were distinguished based on various characterizations. Compared with different doses of Ag/TiO2-NTs, the electrode with the dose of 5.0 × 1017 ions·cm−2 exhibited much higher electrode capacity and greatly enhanced activity in comparison to the pure TiO2-NTs. The modified electrode showed a high capacitance of 9324.6 mF·cm−3 (86.9 mF·g, 1.2 mF·cm−2), energy density of 82.8 μWh·cm−3 (0.8 μWh·g, 0.0103 μWh·cm−2), and power density of 161.0 mW·cm−3 (150.4 μW·g, 2.00 μW·cm−2) at the current density of 0.05 mA. Therefore, Ag/TiO2-NTs could act as a feasible electrode material of supercapacitors.

Surface properties of magnesium improved by Sr ion implantation

Strontium (Sr) ion implantation was conducted to improve the surface properties of pure magnesium through a metal vapor vacuum arc (MEVVA) ion implantation. The x-ray photoelectron spectroscopy investigation demonstrated a Sr-implanted layer of approximately 30 nm in thickness formed on the pure Mg surface and Sr element content as a function of the depth in modified layer was similar to a Gaussian distribution. The atomic force microscopy analysis indicated that the roughness value of the pure Mg apparently decreased and the surface became smoother subsequently to Sr ion implantation. Besides, the nanoindentation measurements demonstrated that the elastic modulus and hardness value of the Sr-implanted Mg were both higher than those of pure Mg. Furthermore, compared with untreated Mg, the Sr-implanted Mg exhibited a more positive corrosion potential and a lower corrosion current density in electrochemical tests, and fewer corrosion damage after 12 h immersion tests in SBF. The results suggested that the corrosion resistance and mechanical properties of pure Mg could be improved through Sr ion implantation.

Confocal total reflection X-ray fluorescence technology based on an elliptical monocapillary and a parallel polycapillary X-ray optics

A total reflection X-ray fluorescence (TXRF) spectrometer based on an elliptical monocapillary X-ray lens (MXRL) and a parallel polycapillary X-ray lens (PPXRL) was designed. This TXRF instrument has micro focal spot, low divergence and high intensity of incident X-ray beam. The diameter of the focal spot of MXRL was 16.5 µm, and the divergence of the incident X-ray beam was 3.4 mrad. We applied this TXRF instrument to the micro analysis of a single-layer film containing Ni deposited on a Si substrate by metal vapor vacuum arc ion source.

Effect of MEVVA ion implantation on fatigue properties of TC18 titanium alloy

To evaluate the effects of implantation on fatigue performance of TC18 alloy, Cr and Zr were implanted into specimens using metal vapor vacuum arc plasma source (MEVVA) with a dose of 1 × l017 ions/cm2. The test results show that the fatigue resistance decreased after Cr implantation and Zr implantation, compared to no implanted specimen. The increase in surface roughness after implantation has been found. To analyze the effects of surface roughness produced by ion implantation, the related surface parameters and estimated effective fatigue stress concentration factors was discussed using A&R model. Apart from the residual surface stress and other factors, the surface roughness may have an influence on the fatigue limits of the implanted samples.