Direct coating of cubic boron nitride with titanium powder under high pressure and high temperature

• A simple method, as a low cost process, is developed for simultaneous synthesis and coating of cBN.
• The crystal growth process has an important role in direct coating of cBN.
• The uniform pure TiN-coated cBN are obtained under HPHT and its residual stress is less than 0.64 GPa.
• A strategy provides useful coated cBN composite materials guidance for simultaneous synthesis and coating of cBN composite materials.

In this paper, we propose a facile one-step method for preparing cubic boron nitride (cBN) composite materials. In this method, the pure titanium nitride (TiN) coatings are grown on cBN at 5.0 GPa and 1400–1650 °C during a crystal growth process. We investigate the composition and the microstructure of the coatings. The results indicate that the uniformity of TiN coatings formed on cBN surface can be controlled by the temperature and Ti powder content. The average residual stress of TiN-coated cBN is less than 0.64 GPa. We find that the crystal growth process plays an important role in direct coating of cBN. This one-step method of direct coating of cBN is an effective way to facilitate the preparation of coated cBN composite materials.