Low-Temperature Solid-State Phase Transformations in 2H Silicon Carbide

摘要

Single crystals of 2H SiC were observed to undergo phase transformations at temperatures t+2 tf as low as 400 C. Some 2H crystals transformed to a structure with one-dimensional disorder along the crystal c axis. Others transformed to a faulted cubic6H structure. The transform ation is time and temperature dependent and is greatly enhanced by dislocations. Observations indicate that the transformation takes place by means of a slip process perpendicular to the c axis. Cubic SiC crystals were observed to undergo a solid state transformation above 1400 C. (Author)