Extending the Service Life of Gas Turbine Hardware: (II) Engine Testing

Abstract

An engine test program was undertaken to evaluate a novel component repair process. First stage, high pressure turbine airfoils with either a simple aluminide (Codep on Rene’80) or a high activity Pt aluminide (RT-22 on Rene’142) were studied. Components refurbished with a partial strip, repair and CVD recoat process were installed in rainbow rotors which included new airfoils and/or components with full repairs (complete strip, weld repair and recoat). Following engine service on commercial aircraft, airfoils from the rainbow rotors were examined. The results of the evaluation suggest the desirable qualities of the CVD low activity Pt aluminide coat/overcoat process observed in the laboratory study could be achieved on engine hardware. Hence, a novel repair process is now available to turbine users, which may extend the service life of expensive turbine hardware.