Patent ID: 6620465
Filing Date: 2003-09-16
Classification: C23C,Y10T

Abstract:
A method for applying thermal barrier coatings of variable thermal conductivity to a plurality of turbine airfoils using a physical vapor deposition apparatus that includes an evacuated vacuum chamber containing a pair of ingots and a pair of high energy sources to melt and vaporize the ingot material to disperse vapors therefrom, comprising the steps of:evacuating the vacuum chamber; placing a plurality of airfoils in the vacuum chamber for a preselected time over the ingots and at preseleted distances from the ingots, the distances selected so that the thermal conductivity of applied coating decreases with increasing distance from the ingots; directing beams from the high energy sources onto the ingots so that melt pools are formed on top of the ingots from which the ingot material is vaporized, at least a portion of the vapors from the ingots being deposited on each airfoil to form a coating; maintaining the vaporization of the ingot material until a predetermined thickness of coating is established on the surface of the airfoils, the thermal conductivity of the applied coating on each airfoil decreasing with increasing distance from the ingot and the thickness of the coating decreasing with increasing distance from the ingot so that the ratio of thermal conductivity to thickness of the coating on the airfoils is substantially constant.