Structure Formation during Liquid-Phase Sintering of the Diamond-Containing Composites with Sn-Cu-Co-W Binders

Abstract

Structure formation of diamond-containing composites with Sn-Cu-Co-W binders has been studied within the range of sintering temperatures of 780–820°C. The specimens were obtained by rolling the paste-like mixtures of metallic powders and diamonds on steel substrates, with sintering performed in vacuum. The structure of the sintered specimens was studied by optical metallography, X-ray diffractometry and electron probe microanalysis. Hardness of the materials was identified by Rockwell method (scale B). It has been found that the process of composites sintering is largely affected by oxide films available on the surface of the powders. In order to obtain composites having less than 10% porosity and up to 96–98 HRB hardness, they have to be sintered at the temperature of 820°C which eliminates the oxide films.