METHOD FOR REMOVING HIGH TEMPERATURE CORROSION PRODUCT FROM DIFFUSION ALUMINIDE COATING

摘要

PROBLEM TO BE SOLVED: To remove high temp. corrosion products from the surface of parts without damaging protective coating by immersing gas turbine engine parts into an acetic acid-contg. liq. soln. for a specified time, applying ultrasonic energy on the soln. holding the surface to a specified temp. and executing stirring. ;SOLUTION: Gas turbine engine parts protected with diffusion aluminide coating are, if rquired, subjected to caustic soln. treatment at about 100 to 3,000 psi at about 150 to 250°C to remove oxides, moreover, ceramics coating is removed by water jet stripping, and, after that, it is immersed into a liq. soln. contg. about 4 to 8 wt.% acetic acid for ≥2 hr. This soln. is held to about 150 to 170°F, the immersed parts surface is applied with ultrasonic energy, and stirring is executed. In this way, high temp. corrosion products are removed without damaging the protective coating. Next, the soln, is rinsed away from the surface, thereafter, aluminizing treatment is executed, and the diffusion aluminide coating is easily repaired so as to be reutilizable.;COPYRIGHT: (C)2000,JPO