Patent ID: 7653994

Claim:
A method for repairing a gas turbine stationary flowpath shroud comprising the steps of: providing a superalloy gas turbine stationary flowpath shroud that has previously been in service, wherein the superalloy is selected from the group consisting of nickel-base superalloy and cobalt-base superalloy, the shroud comprising a flowpath surface; preparing a restoration coating for application to the flowpath surface of the shroud by the steps of: providing a precursor mixture comprising: a higher-melting-point alloy component; a lower-melting-point alloy component; and a fugitive binder; and forming a mildly curved restoration preform from the precursor mixture; sintering the restoration preform at a preselected sufficiently high temperature to melt the lower-melting-point alloy component for a preselected period of time sufficient to partially densify the restoration preform and burn off the binder, wherein the sintering takes place on a mildly curved plate other than the flowpath surface; and thereafter applying the restoration coating to the flowpath surface by the steps of: attaching the mildly curved partially densified preform to the flowpath surface; and thermally bonding the mildly curved partially densified preform to the flowpath surface by heating the shroud with the partially densified preform for a preselected period of time and at a preselected temperature sufficient to form a metallurgical diffusional bond between the partially densified preform and the flowpath surface thereby forming the restoration coating.