This study investigated the effects of nano aluminum nitride (AlN) on the microstructure and mechanical properties of vitrified bond diamond tools. Raman spectra analysis indicated that added nano AlN helped to protect the diamond crystal structure during sintering. The diffraction peaks of diamond, AlN, Al₂O₃, and a few of SiO₂ crystal were observed in the X-ray diffraction analysis. However, a lower sintering temperature of 690 ^oC in this study decreased the formation of Al₂O₃ and α-SiO₂ phases. Scanning electron microscope images showed that addition of 10 vol% nano AlN into the specimen provided an appropriate wetting and bonding between the diamond grits and the matrix, thus producing the highest grinding ratio (24.1) of the tools and the best workpiece surface roughness. The added amount of nano AlN higher than 20 vol% would trigger gas eruption from the matrix during the sintering process, which produced a larger number of pores and caused the vitrified matrix expansion. The deteriorated microstructure decreased the mechanical properties of vitrified bond diamond tools.

Keywords: Nano AlN, Vitrified bond diamond tool, Microstructure, Grinding ratio