Microstructure and Wear Resistance of N-Doped TiO2 Coatings Grown on Stainless Steel by Plasma Surface Alloying Technology

W-Mo and W-Mo-N surface-modified layers on Ti6Al4V alloy were obtained using a double glow plasma surface alloying technique. The morphology, microstructure, and chemical composition distribution of the modified layers were analyzed by scanning electron microscope, Xray diffraction, and glow discharge optical emission spectrometry. The hardness and toughness of the modified layers were measured using a micro-hardness tester, and dynamic repeating press equipment. The wear resistance in ambient air and the corrosive wear resistance in NaCl solution were evaluated using a ball-on-disk wear tester. The results show that W-Mo and W-Mo-N surface modified layers are composed of the alloying layers which vary in composition and phase form along the depth. A microhardness gradient was observed in the modified-surface layers. The surface hardness of the W-Mo-N and W-Mo modified layers was 25.3 and 14.2 GPa, which is seven-fold and 3.9-fold harder than the Ti6Al4V substrate, respectively. W-Mo and W-Mo-N surface-modified layers significantly improved the wear and corrosion resistance of Ti6Al4V. It seems that the wear resistance of W-Mo and W-Mo-N surface-modified layers in NaCl solution is better than that in ambient air owing to the strong lubricating effect of NaCl solution and the excellent corrosion resistance of the modified layers.

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Tribological Performance of TiAl Based Alloy Treated with Plasma Surface Chromizing Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.1091 ◽

2011 ◽

Vol 189-193 ◽

pp. 1091-1095

Author(s):

Zhi Yong He ◽

Zhen Xia Wang ◽

Ying Qin Wang ◽

Xiao Ping Liu ◽

Zhong Xu

Keyword(s):

Wear Resistance ◽

Room Temperature ◽

Surface Alloy ◽

Wear Volume ◽

Surface Alloying ◽

Plasma Surface ◽

Sliding Test ◽

Plasma Surface Alloying Technique ◽

Plasma Surface Alloying ◽

Wear Condition

TiAl-Cr alloy was prepared on surface of TiAl based alloy by plasma surface alloying technique. The wear resistance of the surface alloy was examined under various wear condition. During the room temperature ball-on-dic sliding test, the TiAl-Cr surface alloy showed reduced friction and improved wear resistance. For the 500°C sliding and room temperature fretting tests, the friction coefficient of TiAl-Cr surface alloy was a little higher than that of TiAl-based alloy, but the wear volume showed significant reducing, the wear resistance was improved obviously. The addition of chromium increases the strength and hardness of the TiAl-based alloy, and therefore the load bearing and anti-adhesion capacity of the surface were also enhanced, these were the main mechanisms for the improvement of wear resistance.

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Multiple Needle Cathodes Plasma Surface Alloying of Ti6Al4V with W-Mo-C-N

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.373-374.426 ◽

2008 ◽

Vol 373-374 ◽

pp. 426-429

Author(s):

Yue Fei Zhang ◽

Xin Chao Bian ◽

Qiang Chen ◽

Guang Qiu Zhang ◽

Yuan Gao

Keyword(s):

Wear Resistance ◽

Layer Structure ◽

Surface Hardness ◽

High Hardness ◽

Surface Alloying ◽

Cathode Plasma ◽

Working Pressure ◽

Plasma Surface ◽

Pure Graphite ◽

Plasma Surface Alloying

A multiple-needle-cathode plasma surface alloying process has been developed for improving the properties of surface hardness, wear resistance and corrosion resistance of Ti6Al4V. The process is carried out at temperatures below 800 °C and facilitates the simultaneous introduction of W, Mo,nitrogen and carbon into the surfaces of Ti6Al4V forming gradient alloying layer structure with an extremely high hardness. The process is performed at working pressure of 30Pa-80Pa with 9-needle-cathode of W80Mo20 alloy rods array and a high pure graphite plate cathode as target electrode. A maximum microhardness is 4-6 times much harder than the substrate. The results show the presence of carbide and nitride ceramics phases contribute to high microhardness and wear resistance. The multiple-needle-cathode discharge plasma treatment is an effective method for improvement of the mechanical and tribological properties of titanium-base alloys by formation of graded diffusion hard surface layers. The present paper describes this novel process and properties characteristics.

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Corrosion and Wear Behavior of Nitrogen-Doped TiO2 Coatings on Stainless Steel Prepared by Plasma Surface Alloying Technique

Materials Science Forum ◽

10.4028/www.scientific.net/msf.687.602 ◽

2011 ◽

Vol 687 ◽

pp. 602-609

Author(s):

He Feng Wang ◽

Bin Tang ◽

Xiu Yan Li ◽

Yong Ma ◽

Chen Quan Yang

Keyword(s):

Stainless Steel ◽

Wear Behavior ◽

Hybrid Coatings ◽

Composition Analysis ◽

Surface Alloying ◽

Corrosion Properties ◽

Plasma Surface ◽

Nitrogen Doped ◽

Plasma Surface Alloying Technique ◽

Plasma Surface Alloying

A novel process has been developed to improve tribological and corrosion properties of austenitic stainless steel (S. S). Titanium nitride coatings were obtained by plasma surface alloying technique. Nitrogen-doped titanium dioxide was synthesized by oxidative annealing the resulted TiNx coatings in air. The microstructure of TiO2coatings was characterized by SEM, GDOES, XPS and XRD, respectively. Simulated body solution (Hanks’ solution, 37°C) was used to characterize the electrochemical corrosion properties of the coatings and substrate. Ball-on-disc sliding wear was applied to test and compare the tribological behaviors of the coatings and substrate against Al2O3ball. Results reveal that the resultant coatings have a layered structure, comprising of N-doped TiO2layer at the top and a diffuse-type interface. Such a hybrid coatings system shows good adhesion with the substrate. Composition analysis shows that the coatings shield the substrate entirely. The N-doped TiO2coatings are anatase in structure as characterized by X-ray diffraction. The electrochemical measurements show that the corrosion potential positively shifts from -0.267 V for bare S. S to -0.275 V for N-doped TiO2coated S. S, and the corrosion current density decreases from 1.3 × 10-5A/cm2to 4.1 ×10-6A/cm2. Under a load of 7.6 N, the coefficient of friction is in the range of 0.27～0.38 for the N-doped TiO2and the wear rate of the coatings is only one-fourteenth of that for untreated 316L S. S. Duplex-treated N-doped TiO2coatings display much better wear resistance and antifriction performance than that of S. S.

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Microstructure and tribological behavior of W-Mo alloy coating on powder metallurgy gears based on double glow plasma surface alloying technology

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb181031022d ◽

2019 ◽

Vol 55 (2) ◽

pp. 227-234 ◽

Cited By ~ 2

Author(s):

D.-B. Wei ◽

H.-X. Liang ◽

S.-Q. Li ◽

F.-K. Li ◽

F. Ding ◽

...

Keyword(s):

Wear Resistance ◽

Powder Metallurgy ◽

Tribological Behavior ◽

Alloy Coating ◽

Nanoindentation Test ◽

Surface Alloying ◽

Plasma Surface ◽

Before And After ◽

Glow Plasma ◽

Plasma Surface Alloying

In the present paper, plasma surface alloying was implemented on powder metallurgy gears to improve its wear resistance based on double glow plasma surface metallurgy technology. A W-Mo alloy coating was obtained in the process. The morphology, microstructure and phase composition were investigated by SEM, EDS and XRD. The hardness was examined by Vickers hardness test and nanoindentation test. The tribological behavior of powder metallurgy gears before and after plasma surface alloying was evaluated on a ball-on-disc reciprocating sliding tribometer under dry sliding condition at room temperature. The results indicate that the W-Mo alloy coating is homogeneous without defects, which includes deposition layer and interdiffusion layer. The average microhardness of powder metallurgy gears before and after plasma surface alloying is 145.8 HV0.1 and 344.4 HV0.1, respectively; Nano hardness of deposition layer and interdiffusion layer is 5.76 GPa, 14.35 GPa, respectively. The specific wear rate of W-Mo alloy coating is lower than original PM gears. The wear mechanism of W-Mo alloy coating is slight adhesive wear. The W-Mo alloy coating prepared by double glow plasma surface alloying technology can effectively improve wear resistance of powder metallurgy gears.

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