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1309 |
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Wednesday, June 04, 2008, Room 05 11:20 AM Characterization 2 Modern characterization offers a good possibility for proofing the reliability and the performance of thermal sprayed coatings |
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Studies on bending strength of plasma sprayed ceramic coatings |
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Shunyan Tao* / Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Zhijian Yin / Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Xiaming Zhou/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Chuanxian Ding/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China |
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Bending strength, comparable to other key mechanical properties such as hardness and elastic modulus, is significant to determine the mechanical response of a plasma-sprayed ceramic coating exposed to certain applied load. In most case of literatures, the bending strength of a coating is reported only as an average value of certain number of measurements by various techniques. Few studies, however, have been carried out to probe into the dependence of the mechanical strength on the loading conditions and the microstructural characteristics of coating materials. In this work, the bending strength of Al2O3 coating, as a typical example of thermal sprayed ceramic coatings prepared by plasma spraying was comprehensively evaluated. It was found that the bending strength measured while the loading is positively parallel to the spray direction is higher than that measured as the loading is perpendicular or reversely parallel to the spray direction. In addition, wider variation in strength values measured, indicated by the Weibull statistics analysis was observed in the case where the loading is reversely parallel to the spray direction. These phenomena described above were discussed in terms of the residual stress distribution within plasma-sprayed coatings and its special layer microstructure. |