An acousto-ultrasonic study of the effect of porosity on a sintered glass system

An assessment of the applicability of an acousto-ultrasonic (AU) technique for the monitoring of porous ceramic systems has been carried out. Sintered glass was used as a model system and it was found that the AU parameters, such as normalized ringdown count, normalized pulse width, velocity and frequency interval (f) between adjacent peaks in the frequency spectra, decrease with increasing porosity. The porosity dependence of the normalized AU parameters has been attributed to attenuation which analysis showed depended on the pore size and content. The velocity and frequency interval changes also depended on pore content but, unlike the normalized parameters, were found to be sensitive to pore shape and size. The decreasing f with increasing porosity was explained in terms of the longer path lengths traversed by the waves in the higher pore-density samples.