Development of Rapid Detection and Evaluation System for Inner and Narrow Defects in Fine Ceramics

研制了陶瓷板上窄裂纹的扫描检测系统。当激光光斑照射在陶瓷板上时，激光在陶瓷内扩散并被裂纹中断。通过检测裂纹两侧辐照度的差异，实现裂纹的自动检测，实验装置采用多角镜扫描激光光斑，光电倍增管检测辐照度在陶瓷上的分布，结果表明：（1）在S/A下，可以自动检测出氧化铝或PZT基片上0.5 μ m宽的裂纹;通过检测裂纹两侧辐照度的差异，确定了裂纹的最佳辐照度为2。(2)长度超过0.1mm的裂纹可以被检测到，然而，为了将裂纹与杂质或空隙分离，必须仅检测长度超过0.6mm的裂纹。(3)提出了一种检测陶瓷板中窄裂纹的方法。该技术实现了制造过程中的在线检测。

The scanning detection system for a narrow crack on a ceramic plate has been developed. When a laser spot is illuminated on a ceramic plate, the laser is diffused within the ceramics and interrupted by the crack. The crack is detected automatically by detecting the difference of irradiants on each side of crack.In the experimental apparatus, the laser spot is scanned with a polygon mirror and the distribution of irradiant on the ceramics is detected with a photo-mulutiplier tube, The results can be summarized as follows(1) The cracks of 0.5mum width in alumina or PZT substrate can be detected automatically at an S/N ratio of 2 by detecting the difference of irradi-ants on each side of crack.(2) The cracks with the length over 0.1 mm can be detected, However, only the crack with the length over 0.6 mm must be detected in order to separate the cracks from an impurity or void.(3) The method for detecting the narrow cracks which exist in a patterned ceramic plate was developed. The in-process inspection in a manufacturing process was realized by this technology.