Abstract
Variations of repulsive load and temperature in a ceramic slab subjected to rapid heating on one side under mechanical three-point restriction, were measured to estimate the thermal fracture stress and thermal shock resistance. The thermal stress at fractured point was estimated by comparing the calculated repulsive load with the experimental one. The temperature dependences of thermal conductivity and thermal diffusivity were introduced in the numerical calculations to realize the practical heat conductive condition. Alumina ceramic having high and changeable thermal conductivity with temperature and mica ceramic having low and constant thermal conductivity were used as the specimens. The thermal fracture stress and thermal shock resistance of slab were easily obtained by measuring the repulsive load at restricted point. The temperature dependences of thermal properties had significant effects on the generated repulsive load and thermal stress. The thermal properties of alumina changed with temperature to induce a significant increase in repulsive load and thermal stress. The thermal fracture stress estimated in the experiments showed lower values than the mechanical three-point bending strength.
