High frequency ultrasonic investigation for ceramic materials to test the manufacturing process

High frequency ultrasonic techniques for nondestructive tests of fine grained ceramic materials are presented. Green and partially sintered are considered. To this purpose, ultrasonic velocities and attenuation were measured and correlated to the porosity degree reached in different phases of the manufacturing process. A physical understanding of the experimental results is achieved by comparing them with the theoretical predictions provided by a self consistent scattering theory introduced in the 1980s. Finally, porosity maps are proposed since they give a comprehensive view of the process quality.