Thermal Shock Test of Capped Piezoelectric Ceramic Tubes.

Piezoelectric ceramic tubes with capped ends are widely used in the construction of underwater sound transducers, although the ceramic bond between end cap and ceramic tube may be subjected to high stress if the thermal coefficient of expansion for the end-cap material is not approximately the same as that for the ceramic. To investigate the effect of temperature change on this bond, twelve capped ceramic tubes were subjected to a series of temperature changes from -51C to 74C to determine their ability to withstand the resultant stress. The tubes or bonds failed only when the temperature change was rapid and the thermal coefficients of expansions for tubes and caps differed by a factor of about 6. Author