Surface properties of laser-treated ceramic materials

Abstract

Laser surface treatment of high alumina refractory ceramics has been applied successfully to produce pore-free, homogeneous and crack-free surfaces. The treated surfaces should lead to an increase in the corrosion and erosion resistance of the materials, due to lower permeability to corrosive species and higher surface hardness, respectively. The corrosion resistance, in particular, can be influenced by the penetration of elements, contact characteristics and surface morphology of the treated surfaces in the service environment. Therefore, it is important to investigate the effect of laser treatment of ceramic materials on the interaction of the surface with the various environmental elements. This work is concerned with an experimental investigation of the water permeability, surface roughness and wetting characteristics of laser treated ceramic surfaces. Laser melted and re-solidified high alumina ceramic surfaces, some containing cracks and some being crack-free, are compared with untreated surfaces and the results are reported. It is found that the treated surfaces are smoother than the untreated surfaces. The untreated surfaces demonstrated considerable non-uniformity in wetting, in contrast to the treated surface. Wetting of the latter appeared to be higher. Water permeability through the treated zone was very small compared to that through the untreated surface, and, negligible in the case of crack-free surfaces.