LASER PROCESSING OF CERAMICS.

Abstract

Results of experiments exploring the feasibility of using a laser heat source for sealing plasma sprayed coatings, toughening ceramic bars, and making ceramic alloy powders are reported. Chemical modification of the coated surfaces in conjunction with surface melting showed promise for controlling craze type cracking. Precipitates which should be beneficial to the toughness of zirconia coatings were developed as a result of laser treatment. Fine, complex microstructures were developed in the surface of ceramic alloy bars and in spherical particles. Strengthening of some bars was indicated but it was limited by the shape and character of the underlying material. Molten droplets of selected ceramic compositions typically solidified into spheres on the order of 40-200 mu m for the range of rotational speeds used. Spheres typically contained porosity which enhances their crushability for powders.