アルミニウム表面に形成したアルミナ溶射膜の強度評価

概要

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We evaluated the strength of thermally sprayed Al_2O_3 on aluminum. The thermally sprayed Al_2O_3 films were processed using low-pressure plasma spraying. The thickness of the thermally sprayed Al_2O_3 was 0.3mm and 0.7mm. We used a 4-point bending test and a heating test to evaluate the strength of the thermally sprayed Al_2O_3. We also investigated the effect of residual stress on the strength by measuring deformation of the thermally sprayed Al_2O_3 after removing the aluminum substrates. The bending strength was 120 MPa, regardless of thickness. We assumed that the bending strength equaled tensile strength because the thermally sprayed Al_2O_3 films were very thin. A crack was generated at 433K, regardless of thickness. The thermal stress was 160 MPa when the crack was generated. It was 40 MPa higher than we estimated. We found that the residual stress was compression stress that measured 40 MPa, which contributed to the prevention of the crack generation. We presume that the tensile strength was lower than the thermal stress because the residual stress was reduced by the relaxing of the stress of the aluminum near the interface in the bending test.
社団法人日本機械学会の論文
2006-05-25