Laser Cladding on Carbon-Carbon Composites

摘要

This report describes the results of experiments on laser cladding a variety of protective coatings onto carbon-carbon substrates as oxidation- protection coatings. The work was performed using a 12-kW flattop CO2 laser and a powder delivery system to inject the material to be deposited into the laser beam at the surface of the sample to be coated. The laser beam is delivered by a series of optics to the substrate, where it is focused to an approximately 1.3- cm-diameter spot size. Most of the test cases used 6 kW/sq cm to clad the coating material to the substrate surface. Coating materials included powdered aluminum, nickel chromium alloy, gray alumina ceramic, and a magnesium oxide/ zirconium oxide ceramic. Mixed results were obtained, with the alumina providing a slightly better cladding, based on visual appearance and micrographic views.