Patent ID: 6943357

Claim:
A method for determining at least one of past-service conditions and remaining useful life of at least one of a component of a combustion engine and a thermal barrier coating thereof, said method comprising: (1) providing a combustion-engine component comprising a thermal barrier coating that comprises at least one photoluminescent (“PL”) material that is capable of being excited by a first radiation at a first wavelength range and is further capable of emitting a second radiation at a second wavelength range different from said first wavelength range in response to said first radiation; said second radiation having a characteristic property that correlates with an amount of a crystalline phase in said thermal barrier coating, which amount changes as said combustion-engine component is exposed to elevated temperatures; (2) directing said first radiation having said first wavelength range at said thermal barrier coating of said combustion-engine component (3) measuring said characteristic property of said second radiation; (4) determining said amount of said crystalline phase present in said thermal barrier coating from said characteristic properly of said second radiation; and (5) determining at least one of past-service conditions and remaining useful life of at least one of said component of said combustion engine and said thermal barrier coating thereof from said amount of said crystalline phase.