異種金属粉末の焼結に関する研究（第1報）銅‐ニッケル混合粉末の焼結について

Abstract

Homogeneity during heat-treatment of 57:43 (by weight) copper-nickel compacts was observed by means of observations of microstructure and X-ray diffraction pattern and measurements of temperature coefficient of electrical resistance. Powder mixtures of copper and nickel, having different particle sizes, were pressed at 30 and 100 kg/mm2. In combination of 100∼120 mesh copper and 100∼120 mesh nickel powders, homogenization was not sufficient for sintering at the condition of 1100°, 2 hr. In combination of fine powders (250∼300 mesh), homogenization seems complete at the temperatures of 1000° and 1100°. Effect of compacting pressure on homogenization was not evident. Weight changes that take place in hydrogen atmosphere during heating of mixed powders and its green compacts pressed at 30 and 100 kg/mm2 were measured up to 900° by thermal balance. By the reduction of oxide film, adsorbed oxygen on particle surface and oxygen entrapped during the pressing operation with hydrogen, water vapour evolves. Adsorbed and entrapped nitrogen evolves at elevated temperature too. Weight decrease of compact pressed at 100 kg/mm2 was smaller than that of powder and of compact pressed at 30 kg/mm2. Then, it seemed that, in compact pressed at 100 kg/mm2, residual water vapour and nitrogen are enclosed in gaps between particles, and those water vapour and nitrogen prevent the interdiffusion between copper and nickel.