Contactless health monitoring in autonomous self-reporting ceramic coatings†

Abstract

Autonomous tracking of structural changes in coated components yields information on materials health and remaining lifetime; but until now, electrical resistance tracking required undesired physical connections between coating and readout. Here, the proof of concept for contactless tracking of phase transformations in autonomous self-reporting Cr–Al–B coatings is demonstrated. Contactless monitored electrical resistance changes of glassy Cr_0.34Al_0.31B_0.35 coatings reveal crystallization, phase formation, and grain growth of Cr₃AlB₄ and Cr₂AlB₂. The hitherto untapped potential of contactless measured electrical resistance data for assessing materials health by tracking structural change is revealed by in situ high-resolution scanning transmission electron microscopy and selected area electron diffraction as well as ex situ X-ray diffraction, and elastic-recoil detection analysis. Continuous or periodic contactless tracking of material health data will enable more efficient and more sustainable materials service by utilizing the individual remaining component lifetime rather than the much shorter lifetime assessment emanating from safety factor-based design approaches.