含窒素WC-β-Co合金に生じる表面部の脱β層

概要

論文の詳細を見る
The formation mechanism off-free layer(βFL) which appears near the specimen surface of WC-β(N)-Co alloys was studied. The alloys were prepared by vacuum-sintering using WC-TiC-TiN solid-solution (β(N)) powders having different compositions.<BR>It was found that the thickness of OβFL decreased with increasing the amount of β(N) (with a fixed com-position) in the alloy, and with increasing nitrogen content in the alloy at a fixed amount of f(N) (with differ-ent compositions), and also with decreasing carbon content in the alloy. The relation, xoct<SUP>1/2</SUP>, wascon firmed, where x is the thickness of βFL and t is the sintering time. From these results, it was concluded that the formation of βFL was rate-controlled by diffusion process, in which nitrogen moves towards the specimen sur-face through the liquid phase during sintering in β-FL, in the same way as in WC-β-Co alloys containing TiN. The mass transfer from the surface layer to the inside of specimen was also examined.
社団法人粉体粉末冶金協会の論文