Characterization of low sintering temperature and high strength SiO2-B2O3-CaO vitrified bonds for diamond abrasive tools

SiO2-B2O3-CaO vitrified bonds are widely used in the fabrication of diamond abrasive tools. The structures and properties of SiO2-B2O3-CaO vitrified bonds with low sintering temperatures and high strength were investigated. Their structures were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR). The bending strength, Rockwell hardness, and thermal expansion coefficients were tested at meantime. The interfacial bonding state between the diamond grains and an optimized 4# vitrified bond was observed by scanning electron microscopy (SEM). The results showed that the thermal expansion coefficients of the varied vitrified bond samples approximated to 7.0 x 10(-6) degrees C-1, the highest bending strength attained was 114 MPa, and the highest Rockwell hardness achieved was 60 HRB. The bending strength displayed regular changes with rising sintering temperatures as did the hardness values. The 4# vitrified bond efficiently wetted diamond grains, enhancing the interfacial bonding strength. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.