Pulsed thermography (PT) as a non-contact non-destructiv
e evaluation (NDE) technique was employed to examine
as-sprayed air plasma spray (APS) thermal barrier coa
tings (TBCs) for quality eval
uation. Thickness and micro-
structural characteristics play a vital ro
le in determining the quality. In this pape
r, PT logarithmic peak second-derivative m
ethod was
adopted to measure the thickness of top coat. Time dependent ther
mal images were used to charac
terize the microstructure which
was
confirmed by scanning electron microscope (SEM). The results
showed that there was relationship between the temperature
distribution of the surface and microstructu
re change in TBCs. Temperature distribution in thermal images and measurement resul
ts
of thickness were in fairly good agreement with the microstructure
change. It can be concluded th
at it was possible to employ t
hese
NDE methods as quality eval
uation for as-sprayed TBCs.