A review article on the CVD processes used to form SiC and Si3N4 by one of the pioneers in this area, Erich Fitzer [Fitzer, E., and D. Hegen, Chemical vapor deposition of silicon carbide and silicon nitride-Chemistry's contribution to modern silicon ceramics, Angew. Chem. Int. Ed. Engl., 18, 295 (1979)], describes the reaction kinetics of the gas-phase formation of these two technical ceramics in various reactor arrangements (hot wall, cold wall, and fluidized bed) for several precursor combinations, as indicated in the accompanying diagram.
(a) Determine the activation energy(ies) for each ceramic/reactor/precursor type.
(b) Comment on what causes the break in two of the curves at high temperatures.
