| 摘要 |
A blade for a fluid flow engine, especially a gas turbine, has a protective coating against injurious attack by the propellant or working medium. A metal blade having a diffusion layer or a sprayed coating for inhibiting corrosion is known. Such coating renders the blade highly resistant against heavily erosive and corrosive attack, especially by pulverized coal combustion gas or similar agents. The present blade is made of ceramic material, especially a dense ceramic material with a surface layer of at least one of the following materials: TiN, TiC, B4C, BN and titanium carbon nitride. These materials are easy to apply and provide a good bond with the ceramic material. If the ceramic materials are silicon carbide (SiC) or silicon nitride (Si3N4) an especially good bond is achieved. This coating strongly resists removal, as it does oxidation and heat. Local removal down to the ceramic material, as it may result from rather long service, is recognizable immediately. These coating materials can be applied to give adequate quality and satisfactory repeatability by using the known CVD (chemically vapor deposited) or the PVD (physical vapor deposited) process. |
