Vacuum Arc Source Research Articles

TRIBOLOGICAL BEHAVIORS OF DUPLEX DLC/Al2O3 COATINGS FABRICATED USING MICRO-ARC OXIDATION AND FILTERED CATHODIC VACUUM ARC SYSTEM

Micro-arc oxidation technique (MAO) treatment produces a layer of alumina film on the surface of the aluminum alloy. A hard and uniform tetrahedral amorphous carbon film (diamond-like carbon, DLC) was deposited on the top of the alumina layer of the 2024 aluminum alloy by a pulsed filtered catholic vacuum arc (FCVA) deposition system with a metal vapor vacuum arc (MEVVA) source. The morphology and tribological properties of the duplex DLC/ Al 2 O 3 coating were investigated by a scanning electron microscope (SEM) and a ball-on-disk sliding tester. These results suggested that the duplex DLC/ Al 2 O 3 coating had good adhesion and a low friction coefficient, which improved significantly the wear resistance of aluminum alloys.

Surface modification of W9Cr4V2Mo high-temperature bearing steel by rare earth ion implantation

Wear and corrosion are the main failure mechanisms of bearings and it is important to prolong their working lifetimes by improving the bearing surface properties. Incorporation of rare-earth elements is one of the viable means in many technologies such as plating, chemical heat treatment, and thermal spraying. In this work, various kinds of rare earth ions including praseodymium, lanthanum and neodymium were implanted into W9Cr4V2Mo high-temperature bearing steel specimens using a metal vapor vacuum arc source. Pin-on-disk wear tests and microhardness and potentiodynamic polarization measurements were employed to evaluate the mechanical properties and chemical stability of the treated specimens. The chemical composition and surface morphology of the implanted layers were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Our results indicate that the tribological characteristics of the treated samples are affected significantly due to the smoother and harder surface, while the enhancement of the corrosion resistance in the 3.5 wt.% NaCl aqueous solution after ion implantation is not appreciable. The modified surface yields better wear resistance.

Hall stratum filtered cathodic arc source for carbon plasma

A novel filtered cathodic vacuum arc source of carbon plasma, in which plasma ions are reflected from a Hall stratum formed in the inter-electrode gap, was studied. The plasma source consisted of a rectangular carbon cathode, positioned between the poles of a permanent magnet, a copper anode, and a triggering mechanism. An arc was operated with current pulses having a duration of 7 ms and a peak current of 200 A. It was shown that the cathode spot plasma jets were reflected from the Hall stratum formed in the arched magnetic field, and bent through 180° towards substrates positioned alongside of the cathode, while macroparticles flew from the cathode spots in straight trajectories. The calculated thickness of the Hall stratum ranged from less than 1 mm to ≥ 10 mm. The ratio of the substrate ion current to the arc current was ∼ 7.5%, which is much larger than that of most known filtered systems, and approaches the plasma transfer efficiency of unfiltered vacuum arc plasma sources.

Surface analysis and oxidation behavior of Y-ion implanted AZ31 magnesium alloys

AZ31 samples were implanted with yttrium ions with fluences of 5×1016, 1×1017 and 5×1017ions/cm2, using a metal vapor vacuum arc source at an extraction voltage of 45kV. The surfaces of the implanted samples were then analyzed by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It was found that after treatment a pre-oxidation layer was formed, and the higher the fluence, the thicker the pre-oxidation layer was. The valence states showed that yttrium existed in the form of Y2O3. Isothermal oxidation tests have been conducted in pure oxygen at 773K for 90min to evaluate the oxidation behavior of the implanted samples. The results indicate that after implantation the oxidation resistance of the samples was significantly improved. Moreover, the greater the fluence, the better the oxidation resistance has been achieved. The characterization of the implanted layers after isothermal oxidation was examined by SEM, AES and XPS. From the results, it can be found that the thickness of the oxide scale formed on the implanted surfaces have been greatly decreased, and there is no obvious change for both the thickness of the pre-oxidation layer and the valence states of the elements after oxidation.

Effects of tantalum ion implantation on the corrosion behavior of AZ31 magnesium alloys

Using a metal vapor vacuum arc source operated at an extraction voltage of 45 kV, AZ31 magnesium alloys were implanted with tantalum ions with doses ranging from 1 × 10 16 to 1 × 10 17 ions/cm 2. After treatment, the depth distribution and valence states of elements in the surface of the samples were analyzed by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS), respectively. The potentiodynamic polarization technique and immersion test were applied to evaluate the corrosion resistance of the implanted samples. It was found that the corrosion resistance of the implanted samples was improved, attributing to the formation of the pre-oxidation layer. The mechanism of the corrosion behavior of the implanted samples was discussed.

Effect of copper ions implantation on the corrosion behavior of ZIRLO alloy in 1 mol/L H 2SO 4

In order to study the effect of copper ion implantation on the aqueous corrosion behavior of ZIRLO alloy, specimens were implanted with copper ions with fluences ranging from 1×10 16 to 1×10 17 ions/cm 2, using a metal vapor vacuum arc source (MEVVA) at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), respectively. Glancing angle X-ray diffraction (GAXRD) was employed to examine the phase transformation due to the copper ion implantation. The potentiodynamic polarization technique was used to evaluate the aqueous corrosion resistance of implanted ZIRLO alloy in a 1 mol/L H 2SO 4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of ZIRLO alloy implanted with copper ions when the fluence is 5×10 16 ions/cm 2. When the fluence is 1×10 16 or 1×10 17 ions/cm 2, the corrosion resistance of implanted samples was bad. Finally, the mechanism of the corrosion behavior of copper-implanted ZIRLO alloy was discussed.

Thin-film photo-catalytic TiO 2 phase prepared by magnetron sputtering deposition, plasma ion implantation and metal vapor vacuum arc source

This study utilizes three methods, magnetron sputtering deposition (MSD), plasma ion implantation (PIII), and metal vapor vacuum arc (MeVVA), to prepare a thin-film TiO 2. The formation of stoichiometrical TiO 2-polymorphs as a layer is regularly relevant to the characteristic of the photo-catalytic effect. TiO 2-polymorphs created at the outermost surface and initiated by efficient photons are still capable to produce superficial hydroxyl groups for subsequent photo-catalytic reactions. The MSD-treated surface with the majority of TiO 2-anatase (101) surface is presently photo-catalytic. The PIII or MeVVA treatment results in an ion-implanted layer of different Ti / O ratios along with the detecting depths, whereas the Ti and O elements in TiO 2 phase at the outermost surface of the layer can be distinguished. Although the PIII- or MeVVA-treated surface is relatively insignificant in photo-catalytic reactions assessed by water droplet contact angle, the consumption of methylene blue in water and antibacterial test, it is still potential to adjust their surface chemistry by improving the quality of the ion-implanted layer, roughening the contact surface area, and increasing the efficiency to regenerate the photo-catalytic reactions. In addition, the ion implantation methods do not alter the size and dimension of a substrate that is a great advantage to employ them for various advanced applications.

Wear resistant and anti-corrosive treatment for TI–6AL–4V using metal vapor vacuum arc source in comparison with plasma immersion ion implantation

This study utilizes two ion-implantation methods, plasma immersion ion implantation (PIII) and metal vapor vacuum arc (MeVVA), to prepare Ti–N phases on the surface of Ti–6Al–4V. By the nitrogen PIII method, both nitrogen and minor oxygen species are simultaneously attracted by the negatively charged substrate. The penetration of N and O interstitial elements to an extensible depth is possible owing to the effect from the negatively charged target. The nitrogen PIII treatment does not produce a novel Ti–N phase. As a result, the modified surface does not behave anticorrosive. The H n and the E determined by nanoindentation also remain unchanged. It is still potential to apply this non-directional treatment by increasing bias voltage of the target, coating pure titanium on Ti–6Al–4V, and adjusting the regeneration process of nitrogen ions. The MeVVA treatment creates a novel αTiN 0.3 (011) phase on Ti–6Al–4V in present study. It signifies that the interactions between kinetic Ti ions of varied energies and minor nitrogen molecules, with minor participation of oxygen, are highly feasible. The novel ion-implanted Ti–N phase is corrosion resistant, which is capable to reduce passivation current density by forming a passive film. Moreover, the MeVVA-treated surface is surface-hardened; the E is simultaneously increased. The increase of nano mechanical properties can be visualized by 3D images using Nano Vision and determined by analyzing the tip/surface impact structure on the indentation site.

Effect of copper ions implantation on corrosion behavior of zirconium in 1 M H 2SO 4

In order to study the effect of copper ion implantation on the aqueous corrosion behavior, specimens of zirconium were implanted with copper ions with fluences ranging from 1 × 10 16 to 1 × 10 17 ions/cm 2, using a metal vapor vacuum arc source (MEVVA) operated at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES), respectively. Transmission electron microscopy (TEM) was used to examine the micro-structure of the copper-implanted samples. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of the implanted zirconium samples in a 1 M H 2SO 4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of zirconium implanted with copper ions. While the corrosion resistance of implanted samples declined with increasing the fluence. Finally, the mechanism of the corrosion behavior of copper-implanted zirconium was discussed.

High current ion sources and injectors for induction linacs in heavy ion fusion

Heavy ion beam driven inertial fusion requires short ion beam pulses with high current and high brightness. Depending on the beam current and the number of beams in the driver system, the injector can use a large diameter surface ionization source or merge an array of small beamlets from a plasma source. In this paper, we review the scaling laws that govern the injector design and the various ion source options including the contact ionizer, the aluminosilicate source, the multicusp plasma source, and the metal vapor vacuum arc (MEVVA) source.

Effect of copper ions implantation on corrosion behavior of zircaloy-2 in 1 M H 2SO 4

In order to study the effect of copper ion implantation on the aqueous corrosion behavior of zircaloy-2, specimens were implanted with copper ions with fluence ranging from 1 × 10 −16 to 1 × 10 −17 ions cm −2, using a metal vapor vacuum arc source (MEVVA) at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), respectively. Transmission electron microscopy (TEM) was used to examine the microstructure of the copper-implanted samples. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zircaloy-2 in a 1 M H 2SO 4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of zircaloy-2 implanted with copper ions compared with as-received zircaloy-2. The corrosion resistance of implanted samples declined with increasing the fluence. Finally, the mechanism of the corrosion behavior of copper-implanted zircaloy-2 was discussed.

The biocompatibility of the tantalum and tantalum oxide films synthesized by pulse metal vacuum arc source deposition

The surface modification technique is extensively employed to improve and control biocompatibility for blood and cell attachment. In this paper, tantalum thin films were synthesized by pulsed metal vacuum arc source deposition, the tantalum oxide films were fabricated by tantalum films heated at 700°C for 1h in air. The films were characterized using X-ray diffraction (XRD). In vitro investigations of cultured human umbilical vein endothelial cells (HUVEC) on Ta, tantalum oxide films, 316L stainless steel and CP-Ti revealed that the growth and proliferation behavior of endothelial cells on the sample surfaces varied significantly. The adherence, growth, shape and proliferation of endothelial cells on tantalum and tantalum oxide films were much better than 316L stainless steel and CP-Ti. The Ta and tantalum oxide films shown to fulfill the requirements necessary for the application as a blood-contacting device (such as stent) coating.

Microstructure and antibacterial properties of AISI 420 stainless steel implanted by copper ions

In order to study the effect of copper ion implantation on the antibacterial property of AISI 420 stainless steel (SS), specimens were implanted by copper ions in a dose ranging from 2 × 10 16 to 5.0 × 10 17ions cm − 2 , using metal vapor vacuum arc source at an extracting voltage of 50 kV. The microstructure, phase compositions and Cu ions concentration profile in the implanted layer were revealed by glancing angle X-ray diffraction, transmission electronic microscopy (TEM) and Auger electronic spectroscopy, respectively. Film attachment method was adopted for evaluation of antibacterial property of specimens against Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus). With TEM, changes of bacterial appearance on the surface of un-implanted SS and annealed Cu-implanted SS were observed separately. Results showed that novel phases such as Fe 4Cu 3 and Cu 9.9Fe 0.1 were formed in the surface layer of the annealed Cu-implanted SS and that the antibacterial property resulted from the Cu-contained and Cu-rich phase which had a damaging effect on pericellular membrane and cell wall. Furthermore, the pericellular membrane was thickened and then the karyon was degraded, and finally, bacteria died. Annealed Cu-implanted SS not only obtains excellent antibacterial property, but also keeps good corrosion resistance which is equivalent to that of common AISI 420 SS.

Influence of titanium ions implantation on corrosion behavior of zirconium in 1 M H 2SO 4

In order to study the effect of titanium ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted with titanium ions with fluence ranging from 1 × 10 16 to 1 × 10 17 ions/cm 2, using a metal vapor vacuum arc (MEVVA) source at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), respectively. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zirconium in a 1 M H 2SO 4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of zirconium implanted with titanium ions. The larger the fluence, the better is the corrosion resistance of implanted sample. Finally, the mechanism of the corrosion behavior of titanium-implanted zirconium was discussed.

Influence of titanium ion implantation on the corrosion behavior of zircalloy-4 in 1 M H2SO4

In order to study the effect of titanium ion implantation on the aqueous corrosion behavior of zircalloy-4, specimens were implanted with titanium ions with a fluence ranging from 1×1016 to 1×1017ionscm−2, using a metal vapor vacuum arc source at an extraction voltage of 40kV. The valence state and depth distribution of the elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy and Auger electron spectroscopy, respectively. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zircalloy-4 in a 1M H2SO4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of zircalloy-4 implanted with titanium ions. The larger the fluence, the better is the corrosion resistance of the implanted samples. Finally, the mechanism of the corrosion behavior of titanium-implanted zircalloy-4 was discussed.

Influence of aluminum ions implanted on corrosion behavior of zirconium in 1 M H2SO4

In order to study the effect of aluminum ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted with aluminum ions with fluence ranging from 1×1016 to 1×1017 ions/cm2, using a metal vapor vacuum arc source (MEVVA) at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES), respectively. Transmission electron microscopy (TEM) was used to examine the microstructure of the aluminum-implanted samples. Glancing angle X-ray diffraction (GAXRD) was employed to examine the phase transformation due to the aluminum ion implantation. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zirconium in a 1 M H2SO4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of zirconium implanted with aluminum ions. Finally, the mechanism of the corrosion behavior of aluminum-implanted zirconium was discussed.

Effect of copper ions implantation on corrosion behavior of zircaloy-4 in 1 M H 2SO 4

In order to study the effect of copper ion implantation on the aqueous corrosion behavior, samples of zircaloy-4 were implanted with copper ions with fluences ranging from 1 × 10 16 to 1 × 10 17 ions/cm 2, using a metal vapor vacuum arc source (MEVVA) operated at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), respectively. Glancing angle X-ray diffraction (GAXRD) was employed to examine the phase transformation due to the copper ion implantation. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zircaloy-4 in a 1 M H 2SO 4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of zircaloy-4 implanted with copper ions when the fluence is smaller than 5 × 10 16 ions/cm 2. The corrosion resistance of implanted samples declined with increasing the fluence. Finally, the mechanism of the corrosion behavior of copper-implanted zircaloy-4 was discussed.

Corrosion resistant Ti–Pd surface alloys produced by high intensity pulsed plasma beams: Part II. Deposition by pulsed implantation doping mode with palladium implantation using a MEVVA source

Surface alloys of Ti–Pd have been produced on titanium foils using high intensity pulsed plasma beams in the pulsed implantation deposition mode, with nitrogen as the plasma gas. Unlike in previous work, the palladium was initially introduced into the titanium foil by ion implantation using a metal vapour vacuum arc (MEVVA) source. The corrosion resistance of the alloys was examined by exposure to 0.1 M H 2SO 4 solution at 80 °C. This environment has been employed previously to evaluate surface treatments for improving the corrosion resistance of titanium foils used in electron beam technology for removal of pollutants from flue gases. The foils reveal high corrosion resistance relative to untreated titanium. The improved behaviour is associated with the shift of the open-circuit potential into the range of passivity of titanium. During exposure to the test solution, palladium is enriched at the alloy surface, with generation of nanoparticles in association with anatase and possibly amorphous titania. The formation of the nanoparticles in a weakly adherent surface layer results in some loss of the palladium.

Corrosion behavior of carbon-implanted zircaloy-4 in 1 M H 2SO 4

In order to study the effect of carbon ion implantation on the aqueous corrosion behavior, samples of zircaloy-4 were implanted with carbon ions with fluences ranging from 1 × 10 16 to 1 × 10 17 ions/cm 2, using a metal vapor vacuum arc source (MEVVA) operated at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES), respectively. Glancing angle X-ray diffraction (GAXRD) was employed to examine the phase transformation due to the carbon ion implantation. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zircaloy-4 in a 1 M H 2SO 4 solution. It was found that a significant improvement was achieved in the aqueous corrosion behavior of zircaloy-4 implanted with carbon ions when the fluence is smaller than 5 × 10 16 ions/cm 2. The higher the fluence, the worse is the corrosion resistance. Finally, the mechanism of the corrosion behavior of carbon-implanted zircaloy-4 was discussed.

Influence of titanium ion implantation on the corrosion behavior of zircalloy-4 in 1 M H 2SO 4

In order to study the effect of titanium ion implantation on the aqueous corrosion behavior of zircalloy-4, specimens were implanted with titanium ions with a fluence ranging from 1 × 10 16 to 1 × 10 17 ions cm −2, using a metal vapor vacuum arc source at an extraction voltage of 40 kV. The valence state and depth distribution of the elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy and Auger electron spectroscopy, respectively. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zircalloy-4 in a 1 M H 2SO 4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of zircalloy-4 implanted with titanium ions. The larger the fluence, the better is the corrosion resistance of the implanted samples. Finally, the mechanism of the corrosion behavior of titanium-implanted zircalloy-4 was discussed.