Surface modification of steel by metal plasma immersion ion implantation using vacuum are plasma source

Employing an improved vacuum are plasma source, metal plasma immersion ion implantation (PIII) is performed on 9Cr18 bearing steel. Titanium, tantalum, molybdenum and tungsten ions are implanted followed by nitrogen PILI to result in a modified surface layer with superior wear resistance. The surface properties of the 9Cr18 bearing steel samples are evaluated by measuring the microhardness, wear property, coefficient of friction, as well as elemental depth profiles and chemical composition of the modified layer. The results show that the wear resistance of the samples treated by metal plus nitrogen PIII is enhanced to a larger degree than that of the samples undergoing nitrogen PIII alone. The XPS results indicate that some nitride phases have been formed in the implanted layer. In this paper, we will also discuss the improvement on the metal vacuum are plasma source and experimental protocols. Using metal and gas PIII, the surface properties of 9Cr18 bearing steel are enhanced significantly. (C) 1999 Elsevier Science S.A. All rights reserved.