Abstract: A cobalt-based alloy composition having a relatively small lanthanum addition and relatively large carbon content provides remarkable oxidation resistance and wear resistance at high temperatures. The cobalt-based alloy composition has a suitable combination of ductility and wear resistance at high temperatures to be effective as a hard face material for limiting the effects of chattering of blades during the operation of a gas turbine engine. Further, the cobalt-based alloy has a suitable combination of ductility, oxidation resistance and wear resistance and thus represents an improved hard facing material for the blade components of gas turbine engine.

Abstract: A method of salvaging a cast article by correcting the dimensional characteristics of the cast article and forming a protective coating. The dimensional differences are determined between pre-repair cast article dimensions and desired post repair cast article dimensions to correct a casting defect in the article. The determination may be made by determining the location and approximate volume of a void in the surface of the article. The determination may also be made by determining an amount of buildup volume required to make at least a portion of the surface of the cast article built up to the desired post repair dimensions. The article is coated in at least an area of the casting defect with a high-density coating material capable of forming a diffusion boundary between the coating material and the article. The coating material may comprise an alloy with substantially no oxide forming constituents so as to avoid the formation of oxide inclusions in the coating material.

Abstract: A method of forming a diffusion coating on the surface of a workpiece, such as a turbine engine airfoil part. A coating is formed on at least selected portions of the workpiece substrate using an electroplating coating process. The coating material is capable of forming a diffusion bond with the workpiece substrate. The diffusion bond is a metallurgical bond between the workpiece and the coating that does not have an interface boundary. This diffusion bond creates a secure attachment between the coating and the substrate, much stronger than the mechanical bond that is originally formed between the coating and the substrate. A sintering heat treatment may be first performed to densify the coating material. After the sintering heat treatment, the hot isostatic pressing treatment is then performed to drive the coating material into the workpiece substrate.

Abstract: A cobalt-based alloy composition having a relatively small lanthanum addition and relatively large carbon content provides remarkable oxidation resistance and wear resistance at high temperatures. The cobalt-based alloy composition has a suitable combination of ductility and wear resistance at high temperatures to be effective as a hard face material for limiting the effects of chattering of blades during the operation of a gas turbine engine. Further, the cobalt-based alloy has a suitable combination of ductility, oxidation resistance and wear resistance and thus represents an improved hard facing material for the blade components of gas turbine engine.