| 摘要 |
PROBLEM TO BE SOLVED: To provide a method by which precise degradation information can be obtained, even when an error pattern wave form is obtained from a thickness measuring point in a back layer, by using the wave form as information source of the degradation information of the multilayer body.SOLUTION: A degradation testing method of a multilayer body comprises a first determination step and a second determination step. The first determination step, for the multilayer body accumulating a surface layer and a back layer determines, when reflection waves of supersonic wave dispatched from the surface layer side to the back layer side are a first reflection wave, a second reflection wave and a third reflection wave in a detection order, whether an intensity of the first reflection wave is within a reference range, and determines that the surface of the surface layer is excessively degraded when it is not within the reference range. The second determination step determines, when the first determination step determines that the intensity of the first reflection wave is within the reference range, whether an intensity of the second reflection wave is within the prescribed range, and determines that the surface layer is internally excessively degraded or interfacially peeled between the surface layer and the back layer when it is not within the prescribed range.SELECTED DRAWING: Figure 17 |
