Co基超合金上に形成させた8mass%Y_2O_3-ZrO_2溶射皮膜のはく離エネルギー評価

概要

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In order to evaluate the delamination strength of Y_2O_3-ZrO_2 ceramics coating deposited on Co-based superalloy with CoNiCrAIY bond coat, the tensile test and the edge-indent test were carried out. When the tensile load is applied to the specimen, the ceramic coating is divided by parallel cracks, and the cracks propagate not only along the interface but also into the bond coat layer until the delamination of top coat. With an additional load, the bond coat layer also delaminates. The equation to obtain the critical strain energy release rate G_Ci/i+1 or the interfacial fracture toughness between i and i + 1-th layers for the coating of (n-1) layers on a substrate is introduced fracture-mechanically, and the experimentally measured G_C1/23 between the ceramic coating layer and the bond coat layer is lower than that between the CoNiCrAIY bond coat layer and the substrate. The delamination energy of ceramic coatings measured by the edge-indent tests almost correspond to G_C1/23. Both the tensile and the edge-indent methods are applicable to evaluate the delamination strength of double layer coating specimen as well as the single layer coating specimen.
社団法人日本材料学会の論文
2001-05-15