Thermal stress resistance and heat-induced damage of silicon carbide materials for laser mirrors

The thermal stress resistance, strength and heat induced damage of silicon carbide manufactured by a sublimation, reaction-bonded technique are investigated over a wide temperature range. An electron-beam method simulating the laser heat loading is developed for determination of the laser damage. The damage induced in the materials by a pulse-mode and steady-state heat loading is quantitatively assessed. It is shown that the heat-induced damage to sublimated silicon carbide under steady heat load is at least the same and, under the pulse load is lower, than that for traditional materials such as Cu, Mo, W.