High temperature fracture toughness of ceramic coatings evaluated using micro-pillar splitting

J. P. Best; J. Wehrs; M. Polyakov; M. Morstein; J. Michler

Scripta Materialia 162 (2019) 190-194

Micro-pillar splitting at temperatures up to 500 °C was used to evaluate the toughness for a series of thin physical vapour deposited ceramic-nitride coatings. When compared to ion beam notched geometries, this testing approach reduces the likelihood of ion impregnation within a material volume where fracture may initiate. A toughness increase with elevated temperature was observed for the nanostructured ceramic coatings; the magnitude of which varied between the coatings. A transmission electron microscopy investigation showed deposition-specific periodic nano-layering within the films as a result of the deposition process, which may explain the observed differences in the toughness trends.

DOI: https://doi.org/10.1016/j.scriptamat.2018.11.013