Methods of forming a porous thermal barrier coating

A method of forming a porous thermal barrier coating, comprising:

• disposing a feedstock material using an air plasma spray process on a substrate to form the porous thermal barrier coating, wherein the feedstock material comprises a gas-forming additive and a thermal barrier coating material, and wherein the disposing comprises controlling a porosity parameter of the porous thermal barrier coating by controlling a temperature of the disposed feedstock material on the substrate using an auxiliary heat source.

A method of forming a porous thermal barrier coating comprising a graded porosity, the method comprising:

• disposing a feedstock material on a substrate to form the porous thermal barrier coating, wherein the feedstock material comprises a gas-forming additive and a thermal barrier coating material, and wherein the disposing comprises forming the graded porosity in the thermal barrier coating by controlling:
• an amount of the gas-forming additive in the feedstock material, a temperature of the disposed feedstock material on the substrate using an auxiliary heat source, or a combination thereof.