Abstract: A process for nitriding materials containing silicon to form a silicon nitride material predominantly in the alpha phase is disclosed which includes nitriding the silicon-containing material by (a) heating the silicon-containing material in an atmosphere containing at least hydrogen in the temperature range of about 0.degree. C. to about 800.degree. C. and (b) thereafter, nitriding the silicon-containing material by subjecting the silicon-containing material to a nitriding atmosphere containing at least nitrogen gas in the temperature range of from about 1000.degree. C. to about 1450.degree. C. to effect nitriding.