1992 Volume 56 Issue 1 Pages 104-110
Austenitic type 304 stainless steel with ion-nitrided at 823∼853 K, using a N2-H2 d.c. glow discharge palsma. On that occasion, thin compound layer mainly composed of γ′-Fe4N was removed by emery paper. Secondly, a thin layer of Ti with a thickness of 0.1 μm was deposited on this nitrided specimen and, subsequently, TiN of 1.7 μm was deposited at about 623 K, using an ion-plating technique. By this complex treatment combining ion-nitriding with subsequent ion-plating, surface hardened layers were composed of (i) a thin outermost coating layer of TiN with the hardness of about Hv2200 and (ii) a thick inner diffusion layer of about Hv1100.
The mechanical properties of the specimens TiN-coated after ion-nitriding were examined compared with the untreated or only TiN-coated specimens. The specimens showed a large improved resistance to wear compared with the untreated specimens and the largest wear resistance among them. As for the corrosion resistance, the specimens were a little inferior to the only TiN-coated specimens, but showed an improved resistance to corrosion compared with the untreated specimens. Concerning the resistance to fatigue limit of the specimens was lowered slightly compared with the only ion-nitrided specimens, but showed a considerable improvement compared with the untreated specimens.
