Surface stress distribution in diamond crystals in diamond–silicon carbide composites

Diamond–silicon carbide composites were sintered at high temperature, up to 2273 K, and high pressure, up to 10 GPa. Raman microscopy was used to map stress distribution in diamond crystals on surfaces of the composites. Splitting of the triple degenerate band of diamond and frequency shifts of its components were used to calculate the magnitudes of stress. Those magnitudes varied with location and reached maximum values near crystals boundaries. Stress depended on the sintering temperature, pressure, and the crystal size and was attributed to differences in thermal expansion coefficients and bulk moduluses of diamond and silicon carbide.