Thermophysical Properties of Ceramic Substrates with Modified Surfaces

Laser induced changes of thermophysical properties using a laser supported modification process have been studied. Metal–ceramic composites have been produced by a laser dispersing process. Two types of substrates have been included, namely, pure Al2O3 and Al2O3 reinforced with 10 mass% ZrO2. As a modifying material during the laser process, hard metal powders like TiN and WC have been applied in order to produce a metal–ceramic composite with a metal concentration between 30 and 50%. Standard measurement techniques such as the laser-flash method and differential scanning calorimetry (DSC) have been used to measure the thermal diffusivity and the heat capacity of the ceramics before and after the laser processing. These properties have been evaluated within a temperature range from room temperature to 1400◦C. The experimental results show that the effective thermal conductivity will be enhanced within the laser modified region. The increase of this heat transport property due to particle dispersion into the ceramic matrix depends on the thermal conductivity of the second-phase material.