Abstract: A method of fabricating a composite nozzle for water-cooled, high temperature gas turbines is provided wherein the nozzle comprises a thermally conducting copper core, a top endwall, a bottom endwall, metal tubing through which water may pass embedded in and extending through the core and into the endwalls and a preformed cladding to protect the nozzle against corrosion. The method utilizes hot isostatic pressure to diffusion bond the nozzle components into an assembly and bond the corrosion resistant cladding to the outer surface of the assembly.