Nitriding of stainless steel in an rf plasma

Abstract

Treatment of stainless steels in an rf-powered nitrogen plasma achieves a much increased rate of nitriding, as well as higher hardness and corrosion resistance than traditional nitriding. Small amounts of adsorbed hydrogen are found to be necessary initially, and the process of nitriding is modeled on the basis of this hydrogen increasing the surface sticking coefficient for nitrogen, which is followed by nitrogen diffusion into bulk in the form of nitrogen-vacancy (weakly bound) pairs. The detailed microstructural role of chromium in the process is also discussed.

Improvement of the Surface Layer of Steel Using Microwave Plasma Nitriding

“…When N 2 and H 2 mixing gases are ionized in the discharge current or in the microwave plasma, the ionized hydrogen ions interact with the steel surface leading to the reduction of oxide. 11) This increases the sticking coefficient for nitrogen ions at the steel surface, 12) which can effectively promote the diffusion of nitrogen into the inner region of the steel.…”

Electronic structure and mechanical properties of plasma nitrided ferrous alloys

“…Plasma nitriding is a well established technology for surface modification of metal alloys, involving a complex interaction mechanism between three different phases, namely gas, plasma, and solid [1][2][3]. Essentially, nitrogen is implanted at rather low energies ( 3 eV) and diffuses at temperatures above 300 8C.…”

Influence of bias voltage on the formation and properties of iron-based nitrides produced by plasma nitriding

“…Considerable effort has been made over past ten years to overcome these problems. Post-discharge nitriding [7], RF nitriding [8], plasma immersion implantation [9,10] and through cage (TC) plasma nitriding [11][12][13][14][15][16][17][18][19][20] have been developed. A basic consideration of these modified nitriding processes is to decouple the plasma generation from the components to be nitrided.…”