Process optimization of large-sized cubic boron nitride single crystal synthesis with Li₃N as catalyst

Abstract

Cubic boron nitride (cBN) was synthesized using cubic press with lithium nitride as the catalyst and hexagon boron nitride as the source material under high temperature and high pressure in this study. The high quality big-sized cBN single crystal can be synthesized with the optimized synthesis process. Comparing two different pressurization process, two different power process and three different heating times, the influence for the quality of cBN single crystal were studied. The results show that the process of gradually elevated pressure, the constant power and 15 minutes heating time are conducive to big-sized cBN crystals synthesis under high temperature and high pressure. Using the optimized synthesis process, the single block output reaches up to more than 120ct, the proportion of cBN crystal bigger than 50 mesh reaches to more than 16%, the static pressure strength of 60/70 mesh single crystal reaches to 30 N. Meanwhile, the cBN single crystals have fewer surface defects. The final result is high quality large-sized cBN single crystal was obtained.

Keywords:

• Li₃N
• cubic boron nitride
• high temperature and high pressure
• synthesis process

Additional information

Funding

This work was supported by the Natural Science Foundation of China (Grant No. 51272139).