PHASE STABILITY OF SILICON CARBIDE IN THE TERNARY SYSTEM Si-C-N

After introductory remarks on advanced techniques for producing silicon carbide of high density and strength the phase stability of silicon carbide against nitrogen is discussed. Thermodynamic calculations are in agreement with experimental results. The stability of silicon nitride in contact with carbon is strongly pressure dependent. In the temperature range between 2200°C and 2500°C nitrogen induces transformation of α-SiC into β-SiC. Under suitable conditions the conversion can be forced repeatedly into both directions.