Improvement on the Performance of Ceramic Gas Turbine Components by Chemical Vapor Infiltration

In the course of developing a high-efficiency ceramic gas turbine capable of withstanding intense heat conditions, we developed a turbine nozzle composed of separate ceramic parts assembled and then wound with ceramic-fiber-reinforced material. We synthesized silicon carbide on the surface of the carbon fiber of a three-dimensional fabric using chemical vapor infiltration (CVI) and a silicon carbide film formed at 1300 K and above. The lower the deposition temperature, the lower the deposition rate, but the differences in the deposition rate on the surface and inside the fabric became smaller. After heat cycle tests, a turbine nozzle model with a matrix formed by CVI exhibited residual strength that was nearly twice that produced by conventional methods. We attribute this to the silicon carbide film formed by CVI inhibiting oxidation damage to the ceramic fiber.