Physical properties of magnetostrictive composite materials with the polyurethane matrix

Purpose: The purpose of this study was to determine the thermal and electrical conductivity of composite materials with the polyurethane matrix reinforced with Tb _0.3Dy _0.7Fe _1.9 particles with different particle size distributions and varying volume concentration. Design/methodology/approach: The investigated samples were obtained by casting of the composite materials with the polyurethane matrix reinforced with Tb _0.3Dy _0.7Fe _1.9 particles. There were determined the samples density, electrical properties (by a resistivity measurements), thermal conductivity (by Physical Property Measurement System with thermal transport option), as well as the metallographic investigations (by stereo microscope). Findings: It was found from obtained results that the resistivity value for composite materials filled with larger particle size Tb _0.3Dy _0.7Fe _1.9 was lower than the smaller particles size filled composites. Moreover, it may be noticed that thermal conductivity has an approximate value for different Tb _0.3Dy _0.7Fe _1.9 particle size and the same its volume fraction in matrix. Simultaneously it was also observed that the thermal conductivity of the composite materials did not depend on the temperature within the tested range from 293 to 333 K. Research limitations/implications: Contributes to research on structure and physical properties of magnetostrictive composite materials with the polyurethane matrix reinforced with Tb _0.3Dy _0.7Fe _1.9 particles. Practical implications: The polyurethane matrix in investigated composite materials causes growth of resistivity, limiting this way losses for eddy currents at the high operating frequency of the transducers. Originality/value: The obtained results show the possibility of manufacturing the magnetostrictive composite materials based on the Tb _0.3Dy _0.7Fe _1.9 particles, with desired physical properties (including thermal and electrical one) in cost effective way in comparison to conventional giant magnetostrictive materials (GMM).