The influence of sintering parameters on the mechanical properties of vitrified bond diamond tools

• Sintering temperature has significant influence on the mechanical properties.
• High sintering temperature causes the graphitization of diamond grit.
• Both hardness and the microstructure determine the grinding ratio of the diamond tool.
• The specimen sintered at 710 °C has the highest grinding ratio.

The aims of this study were to investigate the influence of sintering parameters on the mechanical properties of vitrified bond diamond tools. All of the sintered specimens were examined using a thermal analyzer, an X-ray diffraction analyzer, an X-ray photoelectron spectrometer analyzer, a Raman spectrometer analyzer and a scanning electron microscope. The mechanical properties of the sintered specimens including the radial shrinkage percentage, sintered density, hardness and grinding ratio were also recorded. Experimental results showed that the introduction of nitrogen at a sintering temperature of 500 °C could prevent diamond grit from reacting with oxygen and prevent diamond crystals from forming a graphite structure. The microstructure of the sintered specimen 710-90 indicated that the vitrified matrix and diamond grit had excellent coverage and wetting. After the grinding ratio tests, the surface of the vitrified matrix of specimen 710-90 revealed a brittle failure pattern, indicating that the diamond grit could be easily pulled from the vitrified matrix when the diamond grit was worn and the cutting force increased. Therefore, the diamond grit always kept its sharpness and the workpiece maintained the preferred surface roughness. In this study, specimen 710-90 had the best mechanical properties and highest grinding ratio (57.5).

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