Optimization of timea€“temperature schedule for nitridation of silicon compact on the basis of silicon and nitrogen reaction kinetics

摘要

A timea€“temperature schedule for formation of silicona€“nitride by direct nitridation of silicon compact was optimized by kinetic study of the reaction, 3Si + 2N₂ = Si₃N₄ at four different temperatures (1250?°C, 1300?°C, 1350?°C and 1400?°C). From kinetic study, three different temperature schedules were selected each of duration 20 h in the temperature range 1250?°a€“1450?°C, for complete nitridation. Theoretically full nitridation (100% i.e. 66.7% weight gain) was not achieved in the product having no unreacted silicon in the matrix, because impurities in Si powder and loss of material during nitridation would result in 5a€“10% reduction of weight gain.