Determining Mechanical Properties of Thermally Sprayed Coatings Through Synchrotron X-Ray Diffraction Measurements

Abstract

Thermally sprayed ceramic coatings are commonly used in the aerospace and power generation industry as a protective material for a variety of substrates. The mechanical properties of the coating material are crucial for maintaining the protective functionality of the coating. The material response to external loads is highly influenced by residual stresses developed during the deposition process of the thermally sprayed coating, affecting apparent mechanical properties such as Young’s modulus, hardness, adherence, and wear resistance. Synchrotron X-ray diffraction offers a means to capture in-situ strain data during the indentation process on the surface of the coating. In this study, the Rockwell hardness test has been paired with high-energy X-ray diffraction to study the mechanical behavior of an alumina coating applied on an aluminum substrate by air plasma spraying. The indented coating was evaluated via high-energy X-ray diffraction at 0, 160, 315, and 580 N of indentation load. The strain analysis was performed in two directions, the in-plane (e11) and out-of-plane (e22). A significant strain change was observed when increasing the indentation load from 315 N to 580 N. The results indicated strain relief, which can be associated with damage evolution, such as crack formation. © 2024 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.