| 摘要 |
PROBLEM TO BE SOLVED: To improve high temp. corrosion resistance of a gasturbine blade by using the treatment that comprises subjecting an M-Cr-Al-Y (M is Ni and/or Co) alloy contg. a specified amount of Re to thermal spraying or vapor deposition on a blade material to form an alloy coating layer on the blade material, and thereafter subjecting the coating layer to Cr chemical vapor deposition or diffusion/infiltration treatment. SOLUTION: In this treatment, as the alloy for the coating, an alloy formed by adding a 1 to 12 wt.% of Re to an M-Cr-Al-Y alloy, is used. Preferably, the thickness of the alloy coating layer formed by thermal spraying or vapor deposition is generally adjusted to 100 to 200 μm. The Cr (or Al) chemical vapor deposition treatment of the coating layer comprises: adding AlCl1-3 or CrCl3 vapor to gaseous Ar contg. 1 to 10 vol.% of gaseous H2 ; heating the gaseous mixture to 1,000 to 1,200 deg.C; and then, depositing Cr or Al on such an alloy coating layer. The Cr (or Al) diffusion/infiltration treatment of the coating layer comprises: burying a blade material having such an alloy coating layer, together with powdery Cr or Al, in an Al2 O3 -NH4 Cl powder; and then, heating them in a gaseous H2 atmosphere to 1,000 to 1,200 deg.C. In any of these treatments, the Cr (or Al)-treated layer is formed so that it extends to a 10 to 50 μm depth from the surface of the treated alloy coating layer. |
