Ion implantation modification of special steels in Thailand

Abstract

Various ion implantation methods, including using focused high-density and scanning beams, mixing B-ions to implanted N-ion layers and assisting normal N-ion implantation with both preparative and closing implantations, have been recently developed for modification of special steels in the ion beam center at Chiang Mai University in Thailand. Tool, machinery and structural steel samples in a hardened or unhardened state have been ion-beam-treated. Experimental evidence shows increases in microhardness and improvements in wear resistance for the implanted steels and some particularly impressive modifications. Comparisons are made for ion implantation effects on the tribological property modification of the hardened and unhardened steels between wear conditions of hard ball with heavy load and soft ball with light load. The results indicate that scanning high-density beam N-ion implantation has a potential in strengthening hardened steels, but with a dependence on the Cr as well as C contents, and additional B-ion implantation and multiple N- and B-ion implantation can also effectively strengthen the hardened steels.