抄録
The sintering process of Cu-Si mixed powder compacts was studied by dilatometric and microscopic examination, E. P. M.A. and X-ray diffraction. The sintering process depended on the particle size of added Si powder. The results obtained for Cu-5wt%Si compacts were summarized as follows:
(1) An intermediate η phase (Cu3Si) was produced by solidus diffusion at about 675°C, where an expansion was observed in the Cu-5wt%Si compact with a small particle size Si powder (-250 mesh), and this is due to the pore formation in the vicinity of the interfaces between Si particles and Cu matrix. This rapid diffusion was the first stage leading to homogenization. In consequence, a uniform structure was formed in the Cu-Si compacts with small size Si particles after sintering even at 700°C.
(2) The expansion due to Kirkendall effect was not observed in the Cu-5wt%Si compact with large size Si particles (-100+150 mesh). In this specimen, however, an abrupt expansion occurred at 835°C, and it was caused by the penetration of eutectic (Si+η) liquid into interface between Cu particles, leaving pores at the sites where Si particles were located. Afterwards, a homogenization process proceeded in the region filled with eutectic liquid.
