抄録
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 Al2O3-TiO2 coating on a mild steel (JIS: SS400) specimen by plasma spraying. The delamination energy of coating, Ed, is defined by the following equation based on the indentation load P vs. displacement δ curve:
Ed=∫δ00P·dδ-∫δ0-B10P'·dδ/S×2θ/2π
Where δ0 is the displacement at delamination, B1 is the coating thickness, S is the delamination area, 2θ is the delamination angle and P' is the indentation load only for substrate. The delamination energy Ed of WC-Co coating obtained by experiment reveals almost the same value irrespective of coating thickness B1 and relative indentation distance from edge x/B1. The Ed of Al2O3-TiO2 coating increases slightly with an increase in B1, and the Ed 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.
