ステンレス鋼表面に形成されたクロム拡散被覆層に関する一考察

Abstract

Chromium diffusion coating, such as the Cr powder pack process using chlorides, brings specimens an increase in weight and size. This facts suggest that the position of the specimen surface moves due to Cr deposition on the specimen surface during the coating treatment. Therefore it is supposed that the formation of diffusion coated layer is controlled mainly by the diffusion coefficient of Cr in the substrate, the Cr deposition velocity on the specimen surface, and the diffusion coating time. In the present work, Cr concentration profiles in the diffusion coated layer were calculated approximately according to Fick’s law under a boundary condition that the position of the specimen surface moved with time, and, the changes in surface Cr concentration were explained reasonably. The calculated results were recognized experimentally, too, by electron probe micro-analysis of the chromium diffusion coated layers.