Active thermography method using an CO2 laser for thermal excitation, applied to defect detection in bioceramic materials

This paper presents a non-destructive technique (NDT) using active infrared thermography and a thermal excitation consisting in a CO₂ laser, having a wavelength of 10.6 μm, applicable for bioceramic interior defect detection. For this work we used two samples of bioceramics (Al₂O₃), having the same size, 16 mm diameter and 3 mm thickness. A non-defect sample it was used as the basis for the temperature differences between the healthy and the defective one. In the second sample an internal defect was created. In order to make possible the thermal excitation of the samples it was necessary to deflect the laser beam from vertical to horizontal direction, towards the material. The first advantage of this method represents the detection of internal defects in bioceramic materials, the microscopic method not being reliable in this purpose. The second advantage represents the rapidity of the determinations, just few seconds necessary for internal defect detection.