2018 年 84 巻 863 号 p. 18-00147
We have established the torsion pin test method with tension to evaluate shearing delamination strength of thermal sprayed coating under tension-torsion combined stresses, recently. Apparent delamination strength depends on the diameter of the pin, so the stress distributions around the interface edge between the top-coat and the bond-coat have to be analyzed by using the finite element analysis based on the experimental results to see the real delamination strength. Before analyzing, the deformation properties of the thermal sprayed coating have to be known. In this report, macroscopic elastic deformation properties of the four kinds of porous thermal barrier coating (TBC) is investigated experimentally and analytically. First, the indentation tests are performed to obtain the loading and unloading-depth curves in various load levels, and secondarily Young's moduli are explored by using the unloading-depth curves, Hertz-contact theory and FEM analysis at several loading levels. It becomes clear that the obtained Young's moduli increase with increasing indentation load, which means that the obtained Young's modulus is an apparent modulus of the coating having some structural failure caused by indentation test. As the results, the real Young's moduli are determined at the very small load level with no structural failure for the four kinds of porous thermal barrier coatings.