エッジインデンテーション法による溶射皮膜のはく離強度評価

概要

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In order to evaluate the shear-delamination strength of thermally sprayed coatings, an "edge-indentation method" was newly proposed in the present study, and the method was applied to WC-Co coating deposited on a tool steel (JIS:SKD5) specimen by high-velocity flame spraying and Al_2O_3-TiO_2 coating on a mild steel (JIS:SS400) specimen by plasma spraying. The delamination energy of coating, E_d, is defined by the following equation based on the indentation load Pvs.displacement δ curve: [mumerical formula] Where δ_0 is the displacement at delamination, B_1 is the coating thickness, S is the delamination area, 2θ is the delamination angle and P´ is the identation load only for substrate. The delamination energy E_d of WC-Co coating obtained by experiment reveals almost the same value irrespective of coating thickness B_1 and relative indentation distance from edge x/(B_1). The E_d of Al_2O_3-TiO_2 coating increase slightly with an increase in B_1, and the E_d is smaller than that of WC-Co coating. The edge-indentation method is effective to evaluate the shear-delamination strength especially when the substrate is very hard.
1998-04-15