Fractal characteristics of apparent pores present on polished cross sections of alumina coatings prepared by laser-assisted flame hybrid spraying

A novel laser-assisted flame hybrid spraying process has been developed to deposit alumina coatings on an alumina-based refractory. In this paper, polished cross sections of the alumina coatings, prepared using various process parameters, have been investigated by fractal analysis using an optical microscopy image analysis method. It was evident that both the density correlation functions and the perimeter-area relationships of the apparent pores present on the polished cross sections of the coatings statistically followed fractal laws in nature. Both fractal dimensions, estimated by the density correlation function, and perimeter-area relationships, decreased with increases in laser irradiation intensity. The changes in fractal dimensions suggest that the mechanism of coating, deposition have been changed to some extent by the laser treatment. (C) 2003 Elsevier B.V. All rights reserved.