Monitoring of a ceramic surface temperature field induced by pulsed Nd: YAG laser

Abstract

Temperature distribution induced by laser radiation is a very important parameter for an efficient and safe application of lasers in different ceramic processing techniques. This paper presents the results of an infrared thermography (IRT) application for monitoring temperature distribution on a ceramic surface during Nd: YAG laser irradiation with different fluences and 8ns pulse duration. FLIR, E40 and SC7200 IR cameras were used with the aim of recording the maximum temperature in the irradiated zones. It was expected that IRT could give some information related to the heat affected zone and possible damage to the base material; however, the results have shown that IR cameras, even those with high performance such as SC7200, cannot record the maximum temperature value at the moment of laser operation, but only the average temperature of the bulk sample material after laser pulses. The results of the numerical simulation have confirmed the value of the thermographic measurements. The microstructure and micromorphology of the ceramic surface before and after the laser treatment were analysed by optical and scanning electron microscopy as well as by examining the roughness of the irradiated and non- irradiated surfaces, while the micromechanical changes were analysed by comparing the micro-hardness of the irradiated and non-exposed surfaces.