Laser surface annealing and characterization of Ti2AlC plasma vapor deposition coating on zirconium-alloy substrate

Laser surface treatment of amorphous Ti-Al-C (50:25:25 at.%) coating deposited on Zircaloy-4 substrate by dc magnetron sputtering was parametrically investigated as a function of surface temperature and dwell time. The as-deposited coating was transformed to crystalline Ti2AlC without significant phase alteration of Zircaloy-4 substrate under optimized conditions (900 °C for 3 s). Thermal analysis via commercial finite element software was applied to guide the selection of parameters for laser surface treatment. Coating performance was evaluated with wear and scratch tests as well as high temperature steam oxidation tests. Although laser treatment led to the formation of microcracks, it was noted to improve the mechanical integrity of the coatings and the oxidation tests indicated the protective nature of the as-deposited and laser-annealed coatings. The oxide particulate morphology and size formed during the steam oxidation tests varied dramatically between the as-deposited and laser-annealed coatings.