Synthesis and application of titania-coated ultrafine diamond abrasive particles

In order to improve the oxidation resistance of ultrafine diamonds (UFDs) and broaden their applications in the field of ultra-precision grinding, titania-coated UFDs were prepared successfully with the aid of acetic acid and polyvinylpyrrolidone (PVP). Compared with the pristine UFDs, the oxidation resistance temperature of titania-coated UFDs was enhanced by around 130 degrees C. The titania shell thickness was approximately 4 nm. The hydrolysis rate of titania precursors was controlled effectively, and a mass of isolated titania particles were not formed when pH value of the system was about 5.0. The amphiphilic PVP could be adsorbed easily on the surface of UFDs and subsequently combine with the hydroxyl groups of hydrolyzed TiO2 particles, which stimulated the formation of titania-coated UFDs. In addition, titania-coated UFD-vitrified bond wheels were manufactured through the titania-coated UFD-vitrified bond composite powders obtained by a polyacrylamide gel (P-G) method, with which their mechanical performances were largely improved. These results would provide a new pathway of manufacturing high quality ultra-precision grinding wheels. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.