Comparative research on ultrasonic and THz methods for thickness measurement of thermal barrier coatings

Abstract

Abstract The thickness evaluation of thermal barrier coatings has emerged as a crucial issue, with ultrasonic testing (UT) and THz testing being the two dominant non-destructive evaluation methods. Focusing on thermal barrier coatings, this paper compares the thickness measurement results obtained from these two methods. When compared to the results obtained from a profilometer, the maximum error in ultrasonic thickness measurement is found to be 6.7%, while the maximum error in THz thickness measurement is 5.8%. The paper also discusses the primary advantages and disadvantages of the existing methods, concluding that both approaches can enhance the lifespan and safety of turbine blades.