Some effects of Al and O2 on the nitridation of silicon compacts

Abstract

The influence of a simultaneous decrease of the nitrogen partial pressure and increases of the oxygen potential on the nitridation of Si and Si-6% Al powders has been investigated. The highest final weight gains and densities have been obtained when Si-Al compacts were nitrided in an oxygen enriched atmosphere. These samples were also found to exhibit the most homogeneous microstructures. X-ray diffraction analysis shows that they consist of a β′-Si-Al-O-N solid solution. It is also shown that obtaining only this phase depends, once the nitrogen pressure of the reaction atmosphere has been set, on the adjustment of its oxygen content. Finally, some of the important steps of the overall process, which in the present case appears to be gas flow controlled, are identified and discussed. © 1976 Chapman and Hall.