APPLICATION OF MICROWAVE SELF-HEATING TECHNIQUE TO THE DETECTION OF MICROFRACTURE IN THERMAL BARRIER COATING SYSTEM

摘要

Combination of microwave self heating and thermal imaging techniques has been applied to the evaluation of microfracture behavior in thermal barrier coating system. The plasma sprayed ZrO_2 top coat and NiCoCrAlY bond coat on a stainless steel substrate were used as test specimens. The sphere indentation tests were conducted to introduce damage of interfaces. The damaged coating was radiated by microwave and the change in temperature was monitored. It was found that the method was effective to detect microdamage in the top coat layer.