Double Glow Plasma Surface Metallurgy Research Articles

Tribological Properties of the Fe-Al-Cr Alloyed Layer by Double Glow Plasma Surface Metallurgy

A Fe-Al-Cr alloyed layer was deposited onto the surface of Q235 low-carbon steel via double glow plasma surface metallurgy (DGPSM) to improve the steel’s wear resistance. After the DGPSM treatment, the Fe-Al-Cr alloyed layer grown on the Q235 low-carbon steel was homogeneous and compact and had a thickness of 25 µm. The layer was found to be metallurgically adhered to the substrate. The frictional coefficient and specific wear rate of the sample with a Fe-Al-Cr alloyed layer (treated sample) were both lower than those of the bare substrate (untreated sample) at the measured temperatures (25, 250 and 450 °C). The results indicated that the substrate and the alloyed layer suffered oxidative wear and abrasive wear, respectively, and that the treated samples exhibited much better tribological properties than did the substrate. The formation of Fe2AlCr, Fe3Al(Cr), FeAl(Cr), Fe(Cr) sosoloid and Cr23C6 phases in the alloyed layer dramatically enhanced the wear resistance of the treated sample. In addition, the alloyed layer’s oxidation film exhibited a self-healing capacity with lubrication action that also contributed to the improvement of the wear resistance at high temperature. In particular, at 450 °C, the specific wear rate of treated sample was 2.524 × 10−4 mm3/N m, which was only 45.2% of the untreated sample.

Tribological behaviors of Fe–Al–Cr–Nb alloyed layer deposited on 45 steel via double glow plasma surface metallurgy technique

Double glow plasma surface metallurgy technique was used to fabricate a Fe–Al–Cr–Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of the Fe–Al–Cr–Nb alloyed layer were analyzed by scanning electronic microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate that the 20 μm alloyed layer is homogeneous and compact. The alloyed elements exhibit a gradient distribution along the cross section. Microhardness and nanoindentation tests imply that the surface hardness of the alloyed layer reaches HV 580, which is almost 2.8 times that of the substrate. Compared with the substrate, the alloyed layer has a much smaller displacement and a larger elastic modulus. According to the friction and wear tests at room temperature, the Fe–Al–Cr–Nb alloyed layer has lower friction coefficient and less wear mass, implying that the Fe–Al–Cr–Nb alloyed layer can effectively improve the surface hardness and wear resistance of the substrate.

Preparation and high-temperature oxidation behavior of plasma Cr–Ni alloying on Ti6Al4V alloy based on double glow plasma surface metallurgy technology

To improve the oxidation resistance of Ti6Al4V alloy, it was coated with a Cr–Ni alloy with 20, 40, 60, and 80at.% Ni content using the double-glow plasma surface metallurgy technology. The coatings were dense, uniform, and compact, including a complete structure of deposited layer, interdiffusion layer, and sputtering-affected zone. The effect of Ni content on the isothermal oxidation behavior of coating was investigated at 750, 850, and 950°C. The results show that the oxide scale consisted of NiO and Cr2O3. The morphology and distribution of NiO in oxide scale were affected by oxidation temperature and Ni content. When the Ni content was ≤40at.%, the oxidation resistance of the Cr–Ni alloy coating was enhanced.

Double glow plasma chromizing of Ti6Al4V alloys: Impact of working time, substrate–target distance, argon pressure and surface temperature of substrate

Surface chromizing of Ti6Al4V alloys was achieved by double glow plasma surface metallurgy technology. Effects of working time, substrate–target distance, argon pressure and surface temperature of substrate on chromium coating were investigated in detail. The results show that the structure of coating achieved by double glow plasma surface chromizing includes a complete structure of surface deposited layer, inter diffusion layer and sputtering-affected zone. Working time has a significant effect on the composition, morphology and structure of plasma chromium coating. An increasing number of β-Ti turned into α-Ti and TiCr2 phases precipitated in the inter diffusion layer with rising of surface temperature of Ti6Al4V and working time. Argon pressure and the substrate–target distance mainly affected the surface deposited layer of coating. A multilayered deposited structure appeared in the coating when working time was 5 h, which led to the degradation of coating.

Effect of Nb addition on structure and mechanical properties of FeAl coating

Mild steel was coated by hot-dipping in a molten aluminum bath. The Fe–Al–Nb alloyed coating was prepared by implanting the Nb atoms into the Fe–Al coating using a double-glow plasma surface metallurgy method. The morphology, element distribution and phase composition of the alloyed layer were characterized by OM, SEM/EDX and XRD. Meanwhile, the basic mechanical properties of these two coatings were measured and compared. The results showed that the Nb element exhibited gradient distribution in the Fe–Al coating. And the alloyed layer consisted of pure Nb, Fe2Al5, Fe3Al, AlNb2 and Fe7Nb6 phases. After Nb addition, the microhardness of the Fe–Al coating was improved for the diffusely distributed carbide phases. And the adhesion was enhanced with better plastic deformation. What's more, the nanoindentation tests indicated that the toughness of the Fe–Al coating was improved with a stronger ability to resist plastic deformation and a greater plastic deformation work.

A study on high temperature oxidation behavior of double glow plasma surface metallurgy Fe–Al–Cr alloyed layer on Q235 steel

Abstract The high-temperature oxidation behavior of Q235 steel coated with Fe–Al–Cr by using double glow plasma surface metallurgy method was studied in air at different temperatures of 500, 600 and 700 °C, respectively. The Q235 and the 304 stainless steels were produced as the control samples. Electron microscopy, energy dispersive spectroscopy and X-ray diffractometry were carried out to investigate the surface morphologies, microstructures and phases of alloyed layer before and after oxidation. It showed that the structure of the Fe–Al–Cr alloyed layer was compact without any microstructure defects. This alloyed layer connected with the substrate metal by metallurgical bonding. At the temperatures of 500 and 600 °C, the high temperature oxidation resistance of the Fe–Al–Cr alloyed layer was similar to that of the 304 steel, but 2–3 times higher than that of the Q235 steel. While at 700 °C, the Fe–Al–Cr alloyed layer exhibited much better oxidation resistance than that of the 304 steel (2.5 times) and the Q235 steel (5.5 times). And this was because the special Al distribution (approximate Gaussian distribution) in the Fe–Al–Cr alloyed layer, which displayed the self-healing ability for the oxidation film on the surface of the Fe–Al–Cr alloyed layer in the high temperature oxidation conditions.

The Study about the Effect of Work-Piece Space on Copper-Cerium Alloy Case Thickness and Component

In this paper, the author uses double glow plasma surface metallurgy technology, prepares antibacterial stainless steel with copper-cerium case on its surface, does some research on how work-piece space affects Copper-cerium case thickness and component in the case. According to experiment, we find in the range of 10 mm to 25 mm, copper-cerium case depth firstly increase and then decrease with the distance expands; copper-cerium component first rises and then falls with the work-piece space .When the distance is 15mm, hollow cathode effect forms between two plates, we can obtain ideal copper-cerium alley case.

Nanoindentation behavior of molybdenum surface-modified titanium

By using double glow plasma surface metallurgy technique, the molybdenum (Mo) surface-modified layer on titanium (Ti) was obtained. The corresponding cross-section morphology, phase formation, and element concentration were investigated by optical microscopy, X-ray diffraction (XRD), and glow discharge optical emission spectroscopy (GDOES), respectively. The experimental results indicate that the Mo modified layer is composed of a 1.7 μm pure Mo deposition layer and a 14.3 μm Mo diffusion layer. Along the sample thickness direction, nanoindentation tests were performed on the cross-section of the Mo diffusion layer and the Ti substrate (for the comparison purpose) by Hysitron TI900 TriboIndenter. The 2D and 3D residual indentation profiles of the Mo diffusion layer were obtained by scanning probe microscopy (SPM). The elastic modulus and hardness values of every indent were acquired and analyzed. According to the load-displacement curves, the plastic deformation degrees of the Mo diffusion layer and the Ti substrate were analyzed. It is indicated that the Mo diffusion layer possesses high strength-toughness.

The Effects of Temperature and Time on Cu-Ce Infiltration Layer of 304 Stainless Steel by Double Glow Plasma Surface Metallurgy

The Cu-Ce infiltration layer was formed on 304 Stainless Steel surface by double glow plasma surface metallurgy technology. The effects of heat insulation temperature and heat insulation time on surface alloying concentration, surface hardness and infiltration layer depth were analyzed by comparative test. The results showed: In the experimental range, the contents of Cu and Ce, surface hardness, diffusion layer depth increase with the temperature and time increasing; the deposition layer depth increases with time increasing and decreases with temperature increasing in a certain range.

Wear Resistance of Plasma Surface Copper Infiltrated on 0Cr18Ni9 Stainless Steel

The copper infiltrated stainless steel was formed by double glow plasma surface metallurgy technology on 0Cr18Ni9 steel. A comparative test with untreated samples was carried out. The results indicates that the friction coefficient decreases with the load increasing, and copper infiltrated stainless steel is superior to untreated samples in wear rate and wear resistance, finally makes an analysis of the reasons.

The Effects of Voltage on Cu-Ce Infiltration Layer of 304 Stainless Steel by Double Glow Plasma Surface Metallurgy

The Cu-Ce infiltration layer was formed on 304 Stainless Steel surface by double glow plasma surface metallurgy technology. The effects of source voltage and cathode voltage on surface alloying concentration, surface hardness and infiltration layer depth were analyzed by comparative test. The results showed: In the experimental range, the contents of Cu and Ce, surface hardness, deposition layer depth increase with the source voltage increasing, which is contrary to the cathode voltage; the diffusion layer depth increases with either voltage increasing in a certain range.

Characteristics of Mo–Cr duplex-alloyed layer on Ti6Al4V by double glow plasma surface metallurgy

To improve the wear resistance, a Mo–Cr alloyed layer is prepared on the surface of Ti6Al4V by double glow plasma surface metallurgy. The microstructure and phase constituents of the Mo–Cr alloyed layer are characterized by analyses of SEM and XRD. The results indicate that the alloyed layer is composed of a deposited layer and a diffused layer with thickness of 10μm and 12μm respectively. The modified layer is homogeneous and dense. In the diffused layer the contents of Mo and Cr distributed decreasingly with the depth increasing. Microhardness and nanoindentation tests were carried out to evaluate the mechanical properties of the alloyed layer. The surface hardness reaches 1309HV0.01, and also decreases gradually with the depth increased. The nanoindentation tests show that the alloyed layer has a much smaller displacement and larger elastic modulus than that of the substrate. The tribological behaviors of Mo–Cr duplex-alloyed samples and bare substrate were investigated using a ball-on-disk tribometer under the conditions of lubrication-free at room temperature. Comparing to the substrate, the Mo–Cr alloyed specimen records a lower friction coefficient. The wear mass of Mo–Cr alloyed layer is just 1% of the bare substrate. All the results indicate that the Mo–Cr duplex-alloying has effectively improved the wear resistance of Ti6Al4V.

Improving corrosion resistance of Q235 steel by Ni-Cr alloyed layer

Ni-Cr alloyed layer was formed on surface of Q235 steel by double glow plasma surface metallurgy to improve the corrosion resistance of substrate. The composition and microstructure of alloyed layer was analyzed by SEM and XRD. Potentiodynamic polarization and electrochemical impedance spectroscopy was applied to evaluate the corrosion resistance of the alloyed layer. The results showed working pressure had a great effect on structure of Ni-Cr alloyed layer, and the dense and smooth alloyed layer was prepared at 50 Pa working pressure. Compared with substrate, Ni-Cr alloyed layer exhibited higher corrosion potential, lower corrosion current density and larger charge transfer resistance, which indicated that Ni-Cr alloyed layer significantly modified the corrosion resistance of Q235 steel.

Effects of Cr-Mo Infiltration Source Cathode Different Mixing Proportion on the Thickness of Alloy Layer

Based on the plasma nitriding technique, the double glow plasma surface metallurgy (DG-PSM) technology was developed. This technology is also known as the Xu-Tec Process which utilizes solid metallic elements such as Ni, Cr, Mo, W, Ti, Al, Nb, Zr and their combinations to accomplish plasma surface alloying. Mo-Cr strengthened coating was prepared on the surface of low carbon steel Q235 by this technology. This coating is used to high wear resistant cold die LD steel. By experiment of the three different prescriptions in source cathode, the effect of source cathode composition on the coating has been studied. The technological parameters were as follows: The ratio of Mo and Cr were 2:1, 4:1 and 6:1. The work-piece material is Q235 low carbon steel. Holding time is 4h. Holding temperature 1050°C.Source cathode structure was threadiness. The consequences of composition analysis and microstructure observation results show that, most approaches the purpose of this research is the ratio of Mo and Cr is 6:1, and the alloyed layer has stronger adhesion with substrate.

Investigation of W–Mo alloyed layer synthesised by double glow plasma surface metallurgy

In the present study, the W–Mo alloyed layer was deposited on surface of Ti–6Al–4V. Microhardness and nanoindentation testing was used to evaluate mechanical properties of the alloyed layer. The tribological behaviour of W–Mo alloyed layer was estimated using a pin on disc tribometer. The friction coefficient and the wear mass were measured. Results showed that the tungsten and molybdenum content in the alloyed layer decreased gradually from surface to substrate, while the microhardness decreased gradually as the depth increased. The W–Mo alloyed layer had a smaller penetration depth and larger elastic modulus than the substrate. The friction coefficient of the W–Mo alloyed layer was lower than the substrate. The wear mass of W–Mo alloyed layer was one‐third lower than that of the substrate. It can be attributed to the higher hardness of the W–Mo alloyed layer surface which limited plastic deformation of the friction surface and decreased wear mass.

Study on Surface Metallurgy High Speed Steel Using Double Glow Plasma Technique

Mo-Cr diffusion layer on carbon steels are prepared by double glow plasma surface metallurgy and then treated by ultra-saturated carbonization, quenching and tempering. The content of component is roughly that of high-speed steels (HSS). The results showed that the depth of coating is over 100μm and the content of Mo, Cr alloyed layer is about 20% and 10% respectively. Surface carbon content is over 2.0% after ultra-saturated carbonization. The carbides of the alloyed layer are fine and dispersed, without coarse eutectic ledeburite. X-ray diffraction showed that the carbides are M6C, M2C, M23C6 etc. SEM analyse indicated that the dimension of surface carbide is less 1μm. The abrasion experimental results showed that the relative wear resistance of the treated sample was 2.38 times as that of quenched GCr15.

Cr-Mo Diffusion Layer Made by Double Glow Plasma Surface Metallurgy

Abstract Cr-Mo diffusion layer on carbon steels was prepared by double glow plasma surface metallurgy and treated by ultra-saturated carbonization, quenching and tempering, the excellent wear resistance was obtained. The results indicated that the hardness of surface alloying was up to 1300 Hv 0.025 . The carbides in the alloyed layer were fine and dispersed without coarse eutectic ledeburite. The microstructure of the composite layer indicated that the dimension of surface carbides was less 1μm. The abrasion experimental results showed that the average relative wear resistance of modified-steels was 10.3 times as that of T10 steel by quenching and low tempering. The alloy layer possessed a very strong ability resistance to tempering, and its surface hardness exceeds 595 Hv 0.025 after tempering at 690°C for 4h.

A study on double glow plasma surface metallurgy Mo–Cr high speed steel of carbon steel

Double glow plasma surface metallurgy and heat treatment technology that generated excellent properties reinforcing layer on the surface of Q235 steel was introduced. Using this technology, the alloying elements of Mo, Cr, C can be obtained on the surface of Q235 steel. The content of constituent elements was near or equal to metallurgic high speed steel (HSS). The fundamental principle is that alloying elements Mo, Cr are penetrated into the Q235 steel in a vacuum chamber by glow discharge sputtering so that the content of alloyed layer content was about 20% Mo and 10% Cr on the surface of Q235 steel. Then after ultra-saturated carbonization alloyed constituent was similar to molybdenum HSS with surface carburizing of more than 2.0%. After quenching + low tempering; quenching + cryogenic treatment for 2 h + low tempering; quenching + cryogenic treatment for 16 h + low tempering, it was found that the surface hardness of cryogenic treatment was up to 1600 HV much higher than that without cryogenic treatment. The abrasion test results indicate that carbonization + quenching + low tempering, infiltration of Mo–Cr + carbonization + quenching + infiltration of Mo–Cr + carbonization + quenching + cryogenic processing for 2 h + low tempering and infiltration of Mo–Cr + carbonization + quenching + cryogenic processing for 16 h + low tempering the relative wear resistance was higher by one order in magnitude.