Kazuhiko Ogawa and Tamotsu Fukatsu
The sintering process of carbide and metal powders has been studied by means of metallographical or X-ray diffraction methods. In this investigation, however, the magnetic properties (saturation magnetization and Curie temperature) were measured to reveal a sintering mechanism of Cr3C2 and Ni powders. The main results were as follows : (1) It is observed that there are four stages in the sintering process. In the first stage, article-bonds were not yet formed, but the surface diffusion of chromium atoms into nickel powders occurred. In the second stage, this diffusion process being rapidly promoted, the bonding between adjacent powders starts. After this diffusion process is nearly finished,in the third stage, a rapid densification occurred due to formation of a liquid phase at the eutectic temperature. And then, in the final fourth stage, a remarkable grain growth of Cr3C2 is observed. (2) The structure of the binder phase is a solid solution of Ni-Cr alloys, where the concentration of Cr is changed according to the condition of sintering.
Please do not copy without permission.