Laser gas assisted nitriding of alumina surfaces

摘要

Laser gas assisted nitriding of alumina surfaces is a process for applying a nitride coating to an alumina or alumina-based composite surface. The method involves the step of applying a phenolic resin to the alumina surface in a thin, uniform film. The resin-coated alumina surface is maintained in a controlled chamber at about 8 bar pressure at a temperature of about 175° C. for about 2 hours. The surface is then heated at about 400° C. for several hours in an argon atmosphere. This converts the phenolic resin to carbon. The carbon coated alumina surface is then scanned by a 2 kW laser beam while applying nitrogen under pressure. The end result is the conversion of the alumina at the surface to aluminum nitride, the oxygen being released in the form of carbon dioxide.