Laser remelting of alumina tile surfaces: Corrosion testing in aqueous solution

Laser treatment of alumina surfaces in a nitrogen gas environment was carried out and the corrosion response of the resulting surfaces is examined. The corrosion tests were carried out using 5% NaCl solution for seven days, with continuous steering by a magnetic stirrer. Metallurgical and morphological changes in the laser irradiated region are examined using the scanning electron microscope, optical microscope, X-ray diffraction. It was found that formation of nitride (AlN) compounds was evident with a compact and dense structure formed in the laser irradiated region. Moreover, a few shallow pit sites are evident around the crack tips after the static corrosion tests, especially at a high laser output power.