非金属涂层缺陷的太赫兹时域谱检测

Terahertz time-domain spectrum detection of non-metallic coating defects

涂层内部缺陷易导致其剥离、脱落,严重影响工作性能。太赫兹时域光谱技术具有穿透性强、时间分辨能力高和辐射能量低等特点,可以作为一种新型的无损检测技术。涂层的气泡缺陷在太赫兹时域谱上会表现出明显特征,据此建立了太赫兹透射传播模型,并以常见的环氧树脂胶涂层作为样品,对气泡缺陷进行了太赫兹时域光谱分析。结果表明,利用该模型不仅可以定性地对涂层内有无气泡剥离层进行区分,还可以定量地对气泡厚度、大小进行估算。最终可用于检测截面直径在3.5~8 mm,厚度大于0.6 mm的气泡缺陷。这为非金属涂层起泡、开裂的检测提供了新的思路。

Internal defects inside coating may lead to peeling and falling off, which seriously affects the working performance. Terahertz time-domain spectroscopy technology has the characteristics of strong penetration, high time resolution and low radiation energy, which can be used as a new type of non-destructive testing technology. Since coating bubble defects show obvious characteristics in terahertz time domain spectrum, we established the terahertz transmission propagation model. Common epoxy resin is used as the sample to perform terahertz time-domain spectrum analysis on the bubble defects. The results show that the model can be used not only to determine whether there are bubble peeling layers inside the coating qualitatively, but also to estimate the thickness and size of the bubbles quantitatively. Finally, the proposed method can be used to detect the bubble defects with detection section diameter of 3.5~8 mm and thickness greater than 0.6 mm. This method provides a new idea for the detection of blistering and cracking of non-metallic coating.