Effect of fly ash cenosphere@SiO2 core-shell microspheres on physical properties and microstructures of vitrified bond diamond tools

Abstract

Core-shell structure (FA@SiO2) pore former is employed to fabricate high porosity and low mechanical behavior loss vitrified bond diamond abrasive tools. Four different pore former contents i.e. 2, 4, 6, and 8 wt% are used to fabricate the composites. The effects of content of the FA/FA@SiO2 on the phase, morphology structure, open porosity, fracture strength, as well as Rockwell hardness of the FA/FA@SiO2 pore former in the composite are investigated. With increasing FA/FA@SiO2 content from 0 to 8 wt%, open porosity of the composites increases significantly and fracture strength drops ~15%. As compared with FA composite, FA@SiO2 composite exhibits improved pore structures, thus suppressing dramatically bending strength loss and grade loss while remains high porosity. Moreover, the FA@SiO2 in the matrix facilitates the enhancement of interfacial debonding owing to the high contact area, supported SiO2 interlayer and processes of early crack capture at FA@SiO2/glass matrix interface. Therefore, the 4 wt% FA@SiO2 composite shows superior bending strength and hardness (65.08 MPa; 46.25 HRB), which are 15% and 37% higher than those of 4 wt% FA composites (56.33 MPa; 33.67 HRB).