In this study, we synthesized diamond grains containing cBN particles by adding cBN particles during the synthesis of diamond by the high-pressure high-temperature (HPHT) method. The obtained particles were characterized by Raman spectroscopy. We also investigated the mechanical strength and oxidation resistance of the abrasive grains in air. The results confirmed that cBN particles were trapped inside the diamond grains. In addition, compared with commercial diamond abrasive grains, these diamond particles had high friability and high oxidation resistance in air. These diamond particles have potential as a new diamond abrasive.

Most monocrystalline materials, such as silicon carbide (SiC), gallium nitride (GaN), and sapphire (α-Al₂O₃), are first fabricated in wafer form and then finished by chemical mechanical polishing (CMP). CMP normally requires a different machining platform than that used for lapping and grinding in the roughing process. It would greatly improve efficiency if both roughing and finishing processes could be conducted on the same machine tool. Therefore, we are continuously developing chemo-mechanical grinding (CMG) technology implemented on a rotary in-feed grinding machine to deliver finishing capability equivalent to CMP. This paper describes the development of binder-free abrasive pellets (BAP) to realize a CMG wheel with extremely high concentration of 100 wt%, evaluation of BAP properties, and the performance of the BAP-CMG wheel in sapphire wafer finishing.