Proposal of Implant Type Torsion Test for Estimating Adhesive Strength of Sprayed Coatings

This paper deals with the testing method for estimating the adhesive strength of sprayed coatings by the Implant type specimen loaded torsion because sprayed coatings usually are loaded in shear stress. The shearing strength obtained from this testing method was analysed based on the concept of energy release rate. To obtain the shearing strength of sprayed coatings, we made a new testing machine which can detect as a small stress as a strength of sprayed coatings. Energy release rate was calculated using numerical analysis. The result of the strength obtained from this method was reproducible to plus or minus 10% of a stress. From numerical analysis, the conditions for specimen size, in which the energy release rate caused by the residual stress of each specimen should be equal, was clarified. The energy release rate was useful to estimate the adhesive strength of sprayed coatings.