Effect of Bi2O3 on physical properties of vitrified bond and mechanical properties of diamondcomposites

The microstructures and properties of vitrified bond abrasive tools, which are composed of diamond grains and vitrified bond with varying Bi2O3 doping amounts, were comprehensively investigated. The diamond composites were sintered within the temperature scope of the research work. The results show that the addition of Bi2O3 improved the high-temperature fluidity of vitrified bond and the wettability between vitrified bond and diamond grains; decreased the thermal expansion coefficient of vitrified bond and the open porosity of the diamond composite; and improved the mechanical properties of diamond composites, such as bending strength and Rockwell hardness. The microstructure analysis showed that the diamond grains were closely overlaid by vitrified bond and the composites with 4 wt.% Bi2O3 content exhibited relatively uniform pore distribution.