Mechanochemical reaction and formation of an amorphous nitride phase during ball milling of Si in NH3

The formation of an amorphous SixNyH phase is obtained by a solid-gas mecha nochemical reaction induced by ball milling of Si in NH3 gas. We suggest th at mechanical damage together with absorbed N and H play an important role in the formation and stability of the amorphous SixNyH phase during milling . Transmission electron microscopy, x-ray diffraction, thermal analysis, an d composition analysis have been used to characterize the samples after bal l milling and subsequent annealing. Crystallization of the amorphous phase to alpha-Si3N4 is observed at temperatures above 800 degrees C. (C) 1999 Am erican Institute of Physics. [S0003-6951(99)02946-0].