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针对热障涂层制备过程中的厚度评估问题,通过数值模拟手段研究了光脉冲激励下制备在镍基高温合金上不同厚度的Ni Cr Al Y涂层表面热波瞬态响应规律;在此基础上分析了表面热波相位特征随涂层厚度的变化规律,结果表明特定频率范围的热波相位特征与涂层厚度具有近似线性对应关系,但不同涂层厚度之间的相位差绝对值较小,不利于厚度定量评价;为提高不同厚度涂层之间的热波相位差,提出采用小波分解第二层细节系数对涂层表面热波进行重构,重构热波相位差比原始热波提高了约500倍,有利于提高涂层厚度评价的准确率;最后采用试验手段验证了模拟结果的准确性。
In order to evaluate the thickness of the thermal barrier coatings during the process of thermal barrier coating, the thermal response of the NiCrAlY coatings on nickel-base superalloy was studied by numerical simulation. The results show that the phase characteristics of the thermal wave in a specific frequency range have an approximate linear relationship with the thickness of the coating. However, the absolute value of the phase difference between different coating thicknesses is small , Which is unfavorable to the quantitative evaluation of the thickness. In order to improve the phase difference of the thermal waves between coatings with different thicknesses, the second layer of detail coefficients of wavelet decomposition is proposed to reconstruct the surface thermal wave of the coating surface. Increased about 500 times, which is beneficial to improve the accuracy of coating thickness evaluation; Finally, the experimental results verify the accuracy of the simulation results.