Crystallization and properties of B2O3 doped LZAS vitrified bond for diamond grinding tools

摘要

The effects of B2O3 on the crystallization and properties of Li2O-ZnO-Al2O3-SiO2 (LZAS) vitrified bonds were investigated for diamond grinding tool application. The results show that the [BO3] in the glass structure increased with increasing B2O3 content. The glass transition temperature and the first crystallization peak temperature decreased, while the second crystallization peak temperature increased with increasing B2O3 content. The increase in B2O3 content has a little influence on the value of Avrami exponent (n), keeping two-dimensional crystal growth mechanism. Realized composite with 8 mol% B2O3 of LZAS vitrified bond has a higher crystal volume fraction and a uniform sphere-shaped microstructure. Moreover, vitrified bond B8 exhibits a high bending strength (198 MPa), a good chemical durability (20 days, DR = 3.1 x 10(-9) g/cm(2) min), an appropriate TEC (4.63 x 10(-6)/degrees C) and a good wettability to diamond abrasives, suggesting that it would be a promising material for diamond grinding tool. (C) 2015 Elsevier B.V. All rights reserved.