An important characteristic of thermally sprayed coatings is residual stresses, which are generated from the manufacturing process of coating. These stresses arise from contraction of individual sprayed particles and different thermal expansivities of coating and substrate. Residual stresses are highly affecting the performance of coating in service loading. Thus, an accurate evaluation of residual stresses is important and can not be done by using X-ray diffraction, hole drilling, layer removal method or beam curvature method without knowing the true values of Young's modulus E and Poisson's ratio v. However, the direct values of E and v are not easily obtainable, because coatings are not made separately from substrate. That is why elastic properties of coating materials are usually not well known. [1]
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