Production and structural, magnetic and caloric characterization of bonded magnetocaloric material with high thermal conductivity plastic

In this thesis, the thermal conductivity problem between magnetocaloric materials and bonded materials has been studied. Samples were prepared by mixing TCPoly thermoplastic with high thermal conductivity properties developed by TCPoly and micron-sized Gd powder. The mixing process was carried out at 250-280 oC, which is the melting temperature of the TCPoly material. TCPoly concentration of the prepared samples was determined as 0-15% by weight. These values were selected from literature studies of binder material composition. The microstructure of the samples containing 5%, 10% and 15% TCPoly by weight was examined by Scanning Electron Microscopy (SEM). The magnetic properties of the prepared bonded magnetocaloric samples were measured using a vibrating sample magnetometry device. The temperature and magnetic field dependence of the magnetization of the samples was measured in the temperature range of 270-310 K in applied fields up to 2T. According to the data obtained from these measurements, the adiabatic entropy change SM was calculated by using the Maxwell equation. The magnetization and magnetic entropy change of the different composition of the magnetocaloric samples were investigated. It was observed that the maximum entropy change of the samples decreased with increasing TCPoly content as expected. However it was shown that, the magnetocaloric material bonded with TCPoly thermoplastic may be used in magnetic cooler technology.