| 摘要 |
Soft hexagonal boron nitride crystals of 200-600 microns platelet size are produced from crystals of less than fifty microns particle size by mixing the small crystals with an intermediate metallic nitride such as Li3N, heating the mixture to a temperature between 1100.degree.C and 1550.degree.C for twenty minutes or more, cooling the mixture, and separating off the water soluble material present in the mixture to leave a residue of large crystals of boron nitride. Alternatively, the heating step can be carried out under a pressure of about 40 kilobars. |
