チオシアン酸アンモニウム (NH₄SCN) と硼酸 (H₃BO₃) からの窒化硼素の合成

「六方晶窒化硼素の合成に関する研究」 (第1報)

抄録

This research was carried out as a part of the study on synthesis of hexagonal boron nitride.
Orthoboric acid (B) and ammonium thiocyanate (N) were mixed as starting materials and then put in a porcelain vessel. The four steps heating method was used, namely, the first was held at 100°C for one hour, the second at 140°C for 2 hours, the third at 250°C for 2 hours and lastly at 800°C for 2 hours, as the better condition in a stream of nitrogen and ammonia.
The obtained white product was filtered off, washed with hot water and ethanol and dried. Then the composition and crystalline state of residual sample were examined by a chemical analysis, X-ray diffractometer and under a polarizing microscope. The yield of boron nitride was decided from its content in the product by chemical analysis.
In the mixture of N/B=1 in a nitrogen atmosphere, the yield was only about 25% by weight, but in N/B=2, about 57%, the higher yield.
On the other hand, in a flowing atmosphere of ammonia, the yield was about 83% by weight in the mixture of N/B=1, 94% in N/B=2 and 96% in N/B=5, and inclined to increase with N/B molar ratio.
It is remarkable that direct heating to 800°C in ammonia atmosphere was given the nearly same yield compared with that of the four steps heating method.