The Characterization of Nitrogen Implanted WC/Co

Abstract

ABSTRACTAlthough the mechanical properties of nitrogen implanted cemented carbides show significant improvements in performance over unimplanted specimen, the chemical or physical mechanisms giving rise to these improvements are not well understood. Furthermore, the mechanical properties of the implanted samples under thermal stress may not be stable. This study presents analytical results obtained for a series of nitrogen implanted cemented carbides that were subsequently characterized by Auger Electron Spectrometry (AES) and Thermal Desorption Mass Spectrometry (TDMS). Results show that, in the fluence range of 0.5 to 2.5×1017 N2/cm2, peak nitrogen concentration is linear and reaches a maximum concentration of 25 a/o for the highest fluence and 180 keY energy. During vacuum heating, the implanted nitrogen is evolved rapidly between 600–700°C, which corresponds to an activation energy of approximately 7 kcal/mole (.30 ev). A small quantity of nitrogen is still present after heating to 1000°C, at an estimated average concentration of 3 a/o with little diffusional broadening as a result of post-implant heating.