A. Naoumidis

Thermal shock testing of ceramics with pulsed laser irradiation

The need for a high temperature material, capable of withstanding power densities of 15 kW/cm2, for the first wall of nuclear fusion devices has led to the comparative testing of ceramics for their resistance to thermal shock by different pulse loading techniques, photon, proton, and electron beams. The parameter φ √ t, where φ is the impinging energy flux and t is the pulse length, has been used as an index of thermal shock damage threshold for comparing published results on different kinds of beams over a range of temperatures and pulse lengths. Measurements were made of the thermal damage threshold by pulsed ruby laser radiation on a series of ceramics including TiC coated graphite, TiC coated Mo, TiN coated IN 625. pyrocarbon, and others. The results show reasonably good agreement between the different testing methods within a range of different power densities and pulse lengths from 5 μs to 3 s.