Laser assisted oxide removal

Abstract

A method of forming a thermal barrier coating on a metal part includes laser cleaning a surface of the metal part to remove undesirable oxides and residues from the surface of the part. It further includes depositing an aluminum containing bondcoat on the part and thermally interdiffusing the bondcoat and the part with a heat treatment. Laser cleaning a surface of the bondcoat to remove oxides and debris from the surface forms an alpha aluminum oxide layer on the bondcoat. A ceramic topcoat is then deposited on the alpha aluminum oxide layer at a temperature above 1800° F. (982° C.).

1 . A method of removing a thermally grown oxide layer on a surface of an aluminum containing bondcoat formed on a metal part, and forming at the same time an alpha aluminum oxide layer on the bondcoat, the method comprising:
 laser cleaning the surface of the bondcoat, wherein a surface environment during laser cleaning comprises air, inert gas, water or combinations thereof, and a temperature during cleaning comprises room temperature.   
     
     
         2 . The method of  claim 1 , wherein the aluminum containing bondcoat comprises MCrAlY wherein M is Ni, Co, Fe, Pt, Hf, Si, Fe-base, Ni-base, or Co-base alloys or mixtures thereof. 
     
     
         3 . The method of  claim 2 , wherein the bondcoat is formed by low pressure plasma spray (LPPS), high velocity oxy fuel (HVOF) spray, cathodic arc deposition, or chemical vapor deposition. 
     
     
         4 . The method of  claim 3 , wherein the bondcoat is formed by low pressure plasma spray (LPPS). 
     
     
         5 . The method of  claim 1 , wherein laser cleaning is performed by a laser that is focused at the thermally grown oxide layer. 
     
     
         6 . The method of  claim 1 , wherein laser cleaning is performed with a laser that comprises a YAG (yttrium aluminum garnet), UV (ultraviolet), eximer, CO 2  (carbon dioxide), fiber, or disc laser. 
     
     
         7 . The method of  claim 1 , wherein the laser is a YAG (yttrium aluminum garnet) laser, and wherein a power of the laser comprises up to about 100 watts.