Analysis of the ultrasonic velocity - Young's modulus data of various ceramics leads to good correlation between two quantities. This interrelationship provides the basis for using ultrasonic velocity as a predictor of elastic modulus in porous materials. The general relationship experimentally observed between Young's modulus and ultrasonic velocity is corroborated by elasticity, scattering, powder metallurgy and connected grain theories.

A good correlation has been observed between longitudinal ultrasonic velocity and tensile strength in some ceramics. It has been shown that fabrication parameters used for manufacturing the sintered products also shown good correlation with ultrasonic velocity. Thus ultrasonic velocity is a useful tool for monitoring tensile strength and fabrication parameters of sintered products.

Thermal conductivity of ceramics as a function of porosity is critical physical property to be evaluated in heat transfer. An attempt was made to see whether a relationship exists between thermal conductivity and ultrasonic velocity in ceramics. The good relationship observed between the two quantities suggests that ultrasonic velocity can be used for monitoring thermal conductivity of ceramics. From connected grain model and kinetic theory, such an inter-relationship is predicted between the two quantities upto a temperature of 500°C.

The paper presents an analysis of experimental data of various types of porous materials and demonstrates the relationship between ultrasonic velocity and the physical property of interest and gives the general relationship. The relationship postulated by various theories of propagation of ultrasound are also derived to show the theoretical basis for suggesting ultrasonic velocity as a tool for nondestructive monitoring of the property. The paper demonstrates that measurement of a single experimental parameter, i. e. ultrasonic velocity is useful as a predictor of diverse material properties of porous materials viz. elastic moduli, density, tensile strength, fabrication parameters and thermal conductivity.