Formation of S-phase layer on plasma sprayed AISI 316L stainless steel coating by plasma nitriding at low temperature

Adachi, Shinichiro; Ueda, Nobuhiro

doi:10.1016/j.tsf.2012.05.062

Cited by 34 publications

(26 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, Thomas Lindner reported that HVOF-sprayed stainless steel coating was treated by gas nitriding and nitrocarburizing at low temperatures [19,20]. Additionally, we examined plasma-sprayed AISI 316L stainless steel coatings that were treated by low-temperature treatments below 450 • C [21,22]. As a result, it was recognized that the plasma-sprayed stainless steel coatings had improved wear resistance, similar to steel plates.…”

Section: Introductionmentioning

confidence: 99%

Wear and Corrosion Properties of Cold-Sprayed AISI 316L Coatings Treated by Combined Plasma Carburizing and Nitriding at Low Temperature

Adachi

Ueda

2018

Coatings

Self Cite

View full text Add to dashboard Cite

Cold-sprayed AISI 316L stainless steel coatings are treated to form an austenite phase with excessive dissolved nitrogen (known as the S-phase) by plasma nitriding at temperatures below 450 • C. The S-phase is a hard and wear-resistant layer with high corrosion resistance. However, the S-phase layer formed after only nitriding is thin and the hardness abruptly decreases at a certain depth; it lacks mechanical reliability. We examined two types of combined low-temperature plasma treatment to enhance the mechanical reliability of the S-phase layer: (i) sequential and (ii) simultaneous. In the sequential plasma treatment, the carburizing step was followed by nitriding. In the simultaneous treatment, the nitriding and carburizing steps were conducted at the same time. Both combined plasma treatments succeeded in thickening the S-phase layers and changed the hardness depth profiles to decrease smoothly. In addition, anodic polarization measurements indicated that sequential treatment involving carburizing followed by nitriding for 2 h each resulted in high corrosion resistance.However, plasma-sprayed stainless steel coatings include oxide layers, cracks, and pores in their structure, which deteriorate the corrosion resistance considerably.Cold-spraying is not a fusing process but a solid particle stacking process. Hence, cold-sprayed coatings are without any oxides, similar to a bulk steel structure [23]. It was reported that thick cold-sprayed 316L stainless steel coatings show electrochemical polarization behavior similar to bulk stainless steels [24]. Therefore, it is expected that cold-sprayed AISI 316L coatings can be applied as corrosion protective coatings. Additionally, Villa et al. reported that cold-sprayed 316L coatings can be hardened by cold working during the deposition process, which can also result in increased strength, and the abrasive wear resistance of the coating is in the same order of magnitude as that of coatings produced by HVOF [25]. However, the hardness of the 316L coatings was 358 ± 36 HVN, which is insufficient to apply under severe wear conditions.We have previously reported low-temperature plasma nitriding of cold-sprayed AISI 316L coatings to successfully improve the Vickers hardness to 1200 HV [26]. In particular, remelted AISI 316L coatings by a postlaser treatment had excellent corrosion protection for ordinary steel substrates due to a dense microstructure.However, there is a concern that S-phase layers formed by nitriding without carburizing could be delaminated when an external force is applied, because the hardness of the S-phase layers declines drastically at a certain depth. Low-temperature treatments combining nitriding and carburizing have been reported to result in a milder hardness distribution (with hardness not declining drastically), excellent wear resistance, and thickening of the S-phase layers. There are two types of combined treatments-(i) sequential and (ii) simultaneous. In the sequential treatment, carburizing is followed by nitriding [27][28][29]. Meanwhile, in ...

show abstract

Section: Introductionmentioning

confidence: 99%

Wear and Corrosion Properties of Cold-Sprayed AISI 316L Coatings Treated by Combined Plasma Carburizing and Nitriding at Low Temperature

Adachi

Ueda

2018

Coatings

Self Cite

View full text Add to dashboard Cite

show abstract

“…This step-like distribution was also observed in the surface modified layer of AISI 316L stainless steel plates [27,28]. In another study on plasma-sprayed AISI 316L coating [29], this step-like distribution was not found. It is because, compared with nitrogen, the solid oxides in the coating interacted with the chromium atoms more strongly.…”

Section: Microstructurementioning

confidence: 77%

Effects of Gas Nitriding Temperature on the Surface Properties of a High Manganese TWIP Steel

Xia

Zhao

Xing

et al. 2017

Metals

View full text Add to dashboard Cite

Abstract:The effects of gas nitriding temperature on the cross section morphology, element nitrogen distribution, and surface layer compositions of a cold rolled and pre-strained high manganese austenitic TWIP steel 25Mn-3Cr-3Al-0.3C-0.01N and the corresponding anti-corrosion ability have been studied. The results show that, depending on nitriding temperature, the distribution of element nitrogen and main phase compositions are significantly different in the nitriding layers. At a temperature lower than 500 • C, the main composition in the modified layer is S-phase and the nitrogen concentration linearly decreases from the surface to the center, while Fe 4 N forms with S-phase and a step-like distribution of nitrogen content is present at nitriding temperature of 600 • C. Caused by the increasing of modified layer thickness and the formation of S-phase and Fe 4 N, the surface hardness was obviously enhanced. Anodic polarization curves in 3.5 wt. % NaCl solution indicate that the nitrided processes have a tremendous modification effect on anti-corrosion ability. Moreover, the increase of (111) oriented grain, caused by the elevated nitriding temperature, has a positive effect on the corrosion resistance.

show abstract

“…Plasma nitriding is becoming increasingly popular due to its high nitrogen potential, short treatment time and low environmental impact. [1][2][3][4][5][6][7] However, the components to be treated are subjected to a high cathodic potential in traditional DC plasma nitriding (DCPN), which results in the production of plasma directly on their surface. As a result, edge effect, arcing and hollow cathode occur.…”

Section: Introductionmentioning

confidence: 99%

Effect of Surface Deposits on Nitriding Layer Formation of Active Screen Plasma Nitriding

2016

View full text Add to dashboard Cite

Austenitic stainless steel SUS 316L was nitrided by active-screen plasma nitriding (ASPN) to investigate the effect of surface deposits from the screen on the nitriding layer formation. ASPN experiments were carried out using a DC plasma-nitriding unit. The sample was placed on the sample stage in a oating potential (bias-off) and a cathodic potential (bias-on). The screen, which was SUS 316L expanded metal with 38% open area ratio, was mounted on the cathodic stage around the sample stage. Nitriding was performed in a nitrogen-hydrogen atmosphere with 25% N 2 + 75% H 2 for 18-180 ks at 673 K under 200 Pa by the ASPN process. After nitriding, the nitrided samples were examined using scanning electron microscopy, X-ray diffraction, Vickers microhardness and glow discharge optical emission spectroscopy. From the surface observation of the nitrided sample, deposits were observed on the top surface of the sample nitrided with bias-off whereas deposits were not on that nitrided with bias-on. The nitrogen-expanded austenite (S phase) was formed on the surface of both samples. Layer thickness of the S phase increased with increasing the nitriding time. Additionally, the degree of an increase of the layer thickness of the S phase nitrided with bias-on was approximately 2.5 times greater than that nitrided with bias-off. This result suggests that the ASPN treatment with bias-on is effective for the increase of the nitriding layer thickness.

show abstract

Formation of S-phase layer on plasma sprayed AISI 316L stainless steel coating by plasma nitriding at low temperature

Cited by 34 publications

References 10 publications

Wear and Corrosion Properties of Cold-Sprayed AISI 316L Coatings Treated by Combined Plasma Carburizing and Nitriding at Low Temperature

Wear and Corrosion Properties of Cold-Sprayed AISI 316L Coatings Treated by Combined Plasma Carburizing and Nitriding at Low Temperature

Effects of Gas Nitriding Temperature on the Surface Properties of a High Manganese TWIP Steel

Effect of Surface Deposits on Nitriding Layer Formation of Active Screen Plasma Nitriding

Contact Info

Product

Resources

About