Grünkörpercharakterisierung mit zerstörungsfreien Prüfverfahren

Many investigations have been made for the nondestructive characterization of sintered ceramics. Rules for the procedures could be established. The green ceramic material requires special treatment. Preferably noncontacting methods have to be applied. The paper discusses different possibilities. X-ray methods in form of radiography and computed tomography are well suited to detect defects as pores or inclusions and to characterize the density distribution in the volume of a green ceramic body. Thermal microscopy is applied to investigate the area near the surface (depth from 10 to 100 µm) of the green ceramic material. Microwaves can penetrate relatively thick samples. Different binders lead to significant differences in the complex refraction index. Ultrasonic probes needing no liquid coupling medium are applied to detect density variations in green ceramic samples. Especially for the detection of surface damage, caused for example by machining, optical methods are well suited. An aut omatic optical inspection system including image analysis algorithms is presented. Examples for the application of the different methods are given.