Chemical and Materials Engineering Vol. 2(8), pp. 179 - 189
DOI: 10.13189/cme.2014.020803
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Surface Characteristics of Silicon Nitride Compounds Deposited on Plasma Nitrided Austenitic Stainless Steels 316L


Ahmad Reza Rastkar *, Sepehrdad Akbari
Laser and Plasma Research Institute, Shahid Beheshti University, Tehran 1983969411, Iran

ABSTRACT

Silicon nitride compound deposited by plasma enhanced chemical vapor deposition (PECVD) on plasma nitrided stainless steel 316L using tetraethylorthosilicate (TEOS):H2:N2 mixtures. Plasma nitriding is extensively used to improve the hardness and wear performance of steels. It is also known that silicon nitride compounds can have interesting properties, such as low friction coefficient, high hardness and wear resistance. Therefore the deposition processes were carried out at optimized gas compositions and temperatures in order to obtain a combination of the best mechanical and enhanced tribological properties. The composition and structure of the surface layers were characterized using XRD, Glancing angle X-ray diffraction (GAXRD), optical and EDX built in electron microscopy, Microhardness and pin-on-disc wear tests. The compound of α-Si3N4 was found on the top surfaces of PECVD and plasma nitrided austenitic stainless steel 316 L. The nitride compounds were composed of Fe2–3N, Fe4N in addition to chromium nitride. PECVD treatments substantially improved the hardness and wear resistance of plasma nitrided SS 316 L and reduced the friction coefficient and wear rate of the samples. The investigation showed that the combination of PECVD of organosilicon compounds and plasma nitriding results in superior high hardness, low friction and high wear resistance of treated surfaces if compared to those of conventional plasma nitrided surfaces.

KEYWORDS
PECVD, α-Si3N4, Friction, Hardness, Plasma Nitriding

Cite this paper
Ahmad Reza Rastkar , Sepehrdad Akbari (2014). Surface Characteristics of Silicon Nitride Compounds Deposited on Plasma Nitrided Austenitic Stainless Steels 316L. Chemical and Materials Engineering, 2 , 179 - 189. doi: 10.13189/cme.2014.020803.