Effects of AlN on the thermal and mechanical properties of vitrified bond and vitrified CBN composites

The effects of AlN fillers on the thermal and mechanical properties of vitrified bond and vitrified cubic boron nitride (CBN) composites were systematically investigated. The basic vitrified bond (B2O3-Al2O3-SiO2-Li2O-Na2O-ZnO) and AlN fillers make up the vitrified bond, and then constitute the vitrified CBN composites consists together with CBN grains. When the adding amount of AlN rises from 0 wt% to 8 wt%, the thermal conductivity of the vitrified bond increases from 0.74 W/m K to 1.44 W/m K. 6 wt% AlN-doped-vitrified bond presents the minimum coefficient of thermal expansion and bending strength of 66.35 MPa. The substantial improvement of thermal conductivity may be attributed to the formation of thermal conductive path and new crystalline phase-α-tridymite in the vitrified bond. Microstructure characterization indicates that the main crack deflection and divergency are the primary strengthening mechanisms. Such vitrified CBN composites with good thermal conductivity and mechanical strength might be promising in grinding materials for reducing burn.