TEM studies of nitrides in surface-treated and implanted 12% chrome steel

Abstract

Specimens of alloy steel containing 12% chromium as a major alloying constituent were implanted with 100 keV N₂⁺ ions at a constant fluence of 1 × 10¹⁷ N₂⁺ cm⁻². The estimated specimen temperature during implantation did not exceed 450 K. Two kinds of specimens were used for implantation: electropolished and mechanically polished. Iron nitrides of the Fe₁₆N₂ type and mixed iron chromium nitrides (Cr,Fe)₂Ni_1−x (x = 0–0.5) were found in electropolished samples. In mechanically polished samples the Fe₁₆N₂ nitrides predominated. The influence of markedly different surface layers on nitride formation and their detection by diffraction methods is discussed.