Interaction of Sn-Cu-Co powder materials with diamond in liquid-phase sintering

Abstract

The interaction of the Sn-Cu-Co powder material with diamond in liquid-phase sintering has been studied. The material contained commercially pure metal powders at the following proportion, wt. %: 21 Sn, 46 Cu, 33 Co. Metal powders and synthetic diamonds AS150 were mixed with the organic binder and applied on a steel base. Sintering was performed in vacuum at 820-1100 C. The structure of sintered materials is investigated by X-ray diffractometry, scanning electron microscopy and energy dispersive X-ray microanalysis. It has been found out that at sintering temperatures of over 900 C, the liquid phase wets and dissolves diamonds due to its containing cobalt. When the material is cooled down after sintering, the dissolved carbon crystallizes on the surface of diamonds in the form of graphite flakes, which leads to the formation of a weak layer between diamonds and the metallic matrix.