Crystallization behavior of amorphous silicon nitride added with silicon powder

摘要

The additives may accelerate the crystallization process of amorphous powder and shorten the crystallization time. In this respect, special attention should be paid to the effects of additives on the crystallization process of amorphous silicon nitride powder. In this paper, silicon nitride crystalline powder is prepared by crystallization process of nanosized amorphous silicon nitride powder added with 5% silicon powder at temperatures in the range of 1300-1500 ℃ The complete crystallization time of amorphous silicon nitride powder would be reduced from more than 6 h to 30 min by silicon powder and the factors such as temperature and duration on the crystallization process are investigated. The XRD results indicate that the added silicon powder accelerates the crystallization process of amorphous silicon nitride powder effectively and the final products are mainly α-Si_3N_4 and Si_2N_2O. The SEM results show that most of the crystallization products are in the morphologies of slender columnar and irregular rod. The mechanisms of amorphous silicon nitride crystallization induced by Si are discussed. The crystallization process occurs at the interface of the amorphous powder and the added Si powder.