基于太赫兹时域光谱技术对胶层的固化特性进行分析,研究胶层的消光系数与折射率在固化周期内的变化趋势。利用高斯曲线拟合后的多层胶接结构能量积分值、飞行时间(TOF)的均值和半峰半宽两个特征值来表征多层胶接结构的固化特性。结果表明,固化96 h后,两个特征值的统计结果逐渐稳定。胶层的消光系数和折射率有相同的变化趋势,证明胶层固化在96 h左右基本完成。采用的能量积分值与TOF两个特征值可以间接地作为胶接工艺中固化终点的评价指标,进而提高了材料检测水平。

Based on terahertz time-domain spectroscopy, we analyze the curing properties of the adhesive layer and study the variation trend of the extinction coefficient and refractive index of the adhesive layer during the curing period. To characterize the solidification properties of multi-layer bonded structure, we employ the mean value as well as half peak half width of time-of-flight (TOF) and energy integral value of multi-layer adhesive structure after the Gaussian curve fitting. After curing for 96 h, the statistical results of the two eigenvalues gradually are stabilized. The extinction coefficient and refractive index of the adhesive layer exhibit the same trend, which proves that the curing time of the adhesive layer is approximately 96 h. We can use the two characteristic values of TOF and energy integral value adopted in this experiment as the evaluation index of the endpoint of solidification in the bonding process indirectly so as to improve the testing level of materials.