Desorption of gases from the surface of silicon nitride powders

The influence of fabrication and treatment techniques and of carbon coating onto silicon nitride powders on the process of gaseous component desorption has been studied. The N2, H2O, CO2, and CO molecules, as well as OH and NH radicals, were revealed to be absorbed on the particle surface. Different hydrocarbons are the products of reaction in the gas phase and on the surface. Carbon coating on the powder particle surface alloys one to protect the surface from absorbed gases and from chemosorbed compounds, in particular hydroxylic groups. The results obtained permit one to determine the conditions of intended modification of surface and thermal treatment of powders in order to activate their sintering.