Inhibiting the oxidation of diamond during preparing the vitrified dental grinding tools by depositing a ZnO coating using direct urea precipitation method

• ZnO was coated on the surface of diamond by urea precipitation method.
• ZnO as a barrier coating can promote the oxidation resistance of diamond.
• Vitrified bond diamond composite was fabricated using ZnO-coated diamond powders.
• Bending strength of the composite increased by 25%.

Oxidation of diamond during the manufacturing of vitrified dental grinding tools would reduce the strength and sharpness of tools. Zinc oxide (ZnO) coating was deposited on diamond particles by urea precipitation method to protect diamond in borosilicate glass. The FESEM results showed that the ZnO coating was formed by plate-shaped particles. According to the TG results, the onset oxidation temperature of the ZnO-coated diamond was about 70 °C higher than the pristine diamond. The EDS results showed that ZnO diffused into the borosilicate glass during sintering. As the result, the bending strength of the composites containing ZnO-coated diamond was increased by 24% compared to that of the composites containing pristine diamond.