Papers by Keyword: Direct Nitridation

Abstract: Silicon nitride powders were prepared via direct nitridation of silicon powders diluted with -Si₃ N₄ at atmospheric pressure. The nitridation temperature and time were ranged from1623K to 1823K and from 0 minute to 20 minutes respectively. Based on the relations between the conversion rate of silicon and the time at different temperatures, and using shrinking core model, a simple model for the reaction between silicon and nitrogen was derived. The model showed that the relations between the conversion rate of silicon and the time displayed asymptotic exponential conversion trend. Using this model, the kinetics parameters of nitridation of silicon powder at atmospheric pressure were calculated, including pre-exponential factor in Arrhenius equation, activation energy, effective diffusion coefficient, and the formula of the reaction rate constant.

Abstract: Ultrafine e grain amorphous silicon nitride (Si3N4) powders were produced via direct nitridation process of silicon powders in transport bed. The properties of the nitridation products, such as morphology, phase composition, chemical composition and structure, were examined using standard characterization techniques (SEM, XRD, FTIR, etc). The experimental results showed, in the case of silicon powders with particle size of 2.7μm, the conversion rate of silicon was 53.4% at reaction temperature of 1380°C and reaction time of 2.7minutes, and the products mainly comprised amorphous silicon nitride powders.