Effect of B2O3 on physical properties of LZAS vitrified bond and mechanical properties of diamond composites

• Diamond abrasive tools were made of diamond grains and vitrified bond systems.
• The B2O3 addition improved the flowing ability of vitrified bond.
• TEC of vitrified bond B10 was close to TEC of diamond grains.
• The B2O3 (10 mol%) addition improved the mechanical properties of diamond composites.
• Diamond grains were closely covered by vitrified bond B10.

The properties of vitrified bond abrasive tools, which are composed of diamond grains and Li2O–ZnO–Al2O3–SiO2 (LZAS) vitrified bond with and without B2O3 were comprehensively investigated. The results show that the vitrified bond incorporating 10 mol% B2O3 exhibits a lower refractoriness and a higher fluidity compared with that of vitrified bond without B2O3. Moreover, the thermal expansion coefficient (TEC) of vitrified bond containing 10 mol% B2O3 is very close to the TEC of diamond grains. Meanwhile, the open porosity of diamond composite is decreased from 41% to 29% by incorporating 10 mol% B2O3, which was 28.5% lower than that of vitrified bond without B2O3. The bending strength and Rockwell hardness of the diamond composite are significantly improved when the content of B2O3 reached 10 mol%. SEM observation revealed that the diamond grains were closely overlaid by vitrified bond and diamond composite containing 10 mol% B2O3 exhibited a relatively denser structure. The relation between the structural change and compositional variation by introducing B2O3 was analyzed by Fourier transform infrared spectroscopy (FTIR).