Abstract
In the PROTAL process, a pulsed (10ns) laser irradiation is introduced to prepare the surface simultaneously to the thermal spraying process. The purpose of the laser pre-treatment is to eliminate the contaminants and generate a surface condition favorable to the coating adhesion. This study aims at clarifying the fundamental aspects of laser irradiation effects on metallic substrates. The broad technical applications, which involves various surface conditions, may lead to different phenomena and hence limit our comprehensive understanding of the laser-material interaction. Therefore, all specimens were mechanically polished to a mirror state before the laser treatment, which allows the same surface state. Both morphological and chemical surface modifications were investigated by optical microscopy, SEM observation, roughness measurements. Formation of dispersed craters, which takes place at the superficial defects location, dominates the surface modifications due to localized laser ablation.
