The combination of two laser energy sources for surface modification of high alumina ceramics

Abstract

Alumina-based refractory materials are extensively used in high-temperature applications, such as linings in waste incinerators. A significant problem affecting the performance of these materials is the presence of porosity and material inhomogeneities, which promote molten slag corrosion and chemical degradation. Single laser energy sources have been used in the past to modify the surface properties of such ceramics. A major difficulty during laser surface treatment is solidification cracking due to very large temperature gradients that are developed during processing. The aim of the work presented in this paper is to investigate the surface modification of 60% alumina refractory ceramics by combining two laser energy sources in order to control the thermal gradients and cooling rates so that crack formation can be eliminated. The surface morphologies and cross sections of the treated samples have been examined using optical and scanning electron microscopy (SEM) and compared with those of single laser beam treated samples.Alumina-based refractory materials are extensively used in high-temperature applications, such as linings in waste incinerators. A significant problem affecting the performance of these materials is the presence of porosity and material inhomogeneities, which promote molten slag corrosion and chemical degradation. Single laser energy sources have been used in the past to modify the surface properties of such ceramics. A major difficulty during laser surface treatment is solidification cracking due to very large temperature gradients that are developed during processing. The aim of the work presented in this paper is to investigate the surface modification of 60% alumina refractory ceramics by combining two laser energy sources in order to control the thermal gradients and cooling rates so that crack formation can be eliminated. The surface morphologies and cross sections of the treated samples have been examined using optical and scanning electron microscopy (SEM) and compared with those of single laser b...