Sintering parameters and wear performances of vitrified bond diamond grinding wheels

A glass matrix was chosen to bond diamond grits into vitrified bond diamond grinding wheels. The processing variables included the variation of volume percentages of pore-forming polymer beads, sintering atmosphere, sintering temperature, and sintering time. Thermal mechanical analysis was carried out to identify the shrinking behavior of the composite during sintering, showing that the shrinkage of the composite became significant at temperatures higher than the glass transition temperature of the glass bonding matrix (around 520-600 degrees C). Raman spectra were used to identify the influence of sintering atmosphere on the diamond grits. Results indicated that air atmosphere was required for clean burnout of the pore-forming polymer beads, while an inert atmosphere such as nitrogen was necessary for the high temperature sintering, in order to avoid the oxidation and graphitization of the diamond grits. In the range of the sintering temperature and isothermal holding time investigated in this study, sintering temperature had a greater influence on the wheel's grinding performance than isothermal holding time. The bond hardness and shrinkage percentage closely maintained linear relationships with the isothermal holding time at a sintering temperature of 700 degrees C. A highest grinding ratio was achieved when the diamond wheels were sintered at 700 degrees C for 120 min. (C) 2005 Elsevier Ltd. All rights reserved.