Experimental study of the transport properties of Nd-Fe-B and Sm-Co magnets

The article adduces new reliable experimental data on the thermal conductivity and the thermal diffusivity of hard magnetic materials of brands N35M, N35H, N35SH, as well as YX18, YX24 and YXG22, YXG30 with main components represented by the crystalline phases of Nd2Fe14B, SmCo5 and Sm2Co17 type, respectively. The temperature range from 293 to 773…1273 K has been investigated by laser flash technique with an error of 3—4%. The reference tables of the thermal diffusivity and thermal conductivity coefficients have been developed. The character of the thermal diffusivity changes near the Curie point has been determined. The critical indices and the critical amplitudes have been defined

The influence of remanent magnetization on the thermophysical properties of modern magnetically rigid materials

Temperature dependences of thermal conductivity, thermal diffusivity, enthalpy, heat capacity, density and coefficient of linear expansion of 7 brands of modern magnetically rigid materials have been studied. The experiments were carried out by dilatometry, differential scanning calorimetry, and also by a laser pulse method for determining the thermal diffusivity. First, experiments were carried out to determine the thermophysical properties of samples with remanent magnetization. After that, the samples were demagnetized by heating to temperatures exceeding the Curie temperature, after which the thermophysical properties of the demagnetized samples were measured. The obtained results allow us to state, that the presence of remanent magnetization in the materials studied does not lead to a distinguishable change in the thermophysical properties considered in this investigation

Thermophysical properties of polymer composite materials based on TO-29-2 epoxy binder alloyed with AIN

The results of an experimental study of the volumetric, caloric and transport properties of polymer composite materials based on the TO-29-2 grade epoxy binder alloyed with aluminum nitride (AlN) in a wide range of superconducting power equipment operating temperatures are presented. The influence of the inorganic component on the thermophysical properties of polymer composites has been established

The influence of microstructured surfaces and liquid pulsations on increasing heat transfer in a minichannel

The paper compares two methods for improving the intensification of heat transfer during boiling in a rectangular minichannel. Studies were carried out of the influence of additive structures on the crisis of heat transfer in a minichannel with a two-phase flow, as well as studies of the influence of high-frequency pulsations of liquid flow on the intensification of heat transfer processes during flow boiling

Thermal Properties of Li₂BeF₄ near Melting Point

The LiF–BeF2 system is used as a heat transfer medium in molten salt reactors (MSRs). The thermal diffusivity of Li2BeF4 was studied using the laser flash analysis (LFA) method in solid and transition states. While the thermal diffusivity is shown to decrease slightly in solid-state Li2BeF4, it drops significantly at temperatures close to phase transition. The heat capacity of Li2BeF4 was measured by differential scanning calorimetry (DSC). Some differences were observed between the results obtained in cooling and heating modes. Thermal conductivity was calculated using thermal diffusivity-, density-, and heat-capacity data. The good thermal conductivity of the Li2BeF4 compound in solid and liquid states justifies its use as a heat transfer medium for molten salt reactors