Investigation of Hardness of Backing Material Used in Piezoelectric Transducers

Abstract

Ultrasonic probes / transducers are mainly composed of the main body (holder/case/housing), the piezoelectric element / active material, the backing material, the acoustic matching layer applied to the front face of the probe, the electrical connections and the impedance matching circuits / coils. The ability to transmit ultrasonic power in a single direction strongly depends on the rigid structure of the backing materials used in ultrasonic transducers. For this reason, it has been tried to be investigated the hardness of the backing materials used in ultrasonic transducers by mixing the epoxy materials at different ratios both in volume and by weight. Our goal here is to reach the correct mixture ratios by evaluating the hardness values of epoxy mixtures in different ratios. Hardness measurements were made on the Shore A scale. In the study, the hardnesses of the mixtures prepared in seven different ratios were examined, and in the second part of the study, the hardnesses of the four different mixtures prepared as weight on the basis of the results of the volumetric ratios were investigated. In the last part of the study, tungsten powder, which is used to increase the density of the epoxy material and thus provide better acoustic impedance, was added in different weights to the epoxy material that consisted of adhesive and hardener components and so the final hardness ratios were tried to be determined.