Superhard nanocrystalline silicon carbide films

Nanocrystalline silicon carbide films were deposited by thermal plasma chemical vapor deposition, with film growth rates on the order of 10 mu m/min. Films were deposited on molybdenum substrates, with substrate temperature ranging from 750-1250 degrees C. The films are composed primarily of beta-SiC nanocrystallites. Film mechanical properties were investigated by nanoindentation. As substrate temperature increased the average grain size, the crystalline fraction in the film, and the hardness all increased. For substrate temperatures above 1200 degrees C the average grain size equaled 10-20 nm, the crystalline fraction equaled 80-85%, and the film hardness equaled approximately 50 GPa. (c) 2005 American Institute of Physics.