Kinetic studies of the formation of nanocrystalline chromium silicide-silicon carbide from homogeneous amorphous precursor powders

The kinetics of formation of nanocrystalline chromium silicide and silicon carbide composites from homogeneous amorphous precursor powders has been investigated. This study was conducted in a dynamic argon atmosphere at 1 atm in the temperature range 900–1300 °C for time periods ranging from 3 min to 62 h. Two precursors with different concentration ratios of Cr, Si and C were examined. The phase percentages of the final composites, (1) hexagonal Cr5Si3CX and cubic β-SiC and (2) tetragonal Cr5Si3 and cubic β-SiC, vs. temperature and time were determined using X-ray diffraction. The relationship between the phase percentages of the crystalline material, the processing temperature and time follow the Avrami-Erofeʹev equation (J.D. Verhoeven, Fundamentals of Physical Metallurgy, Wiley, 1975). The activation energies have also been determined, and the formation of nanocrystalline chromium silicide and silicon carbide has been discussed.