Measuring the Specific Heat Capacity of Magnetic Fluids Using a Differential Scanning Calorimeter

The specific heat capacity of magnetic fluids was measured using a heat-fluxtype differential scanning calorimeter (DSC). Magnetic fluids which contain 10 to 43 wt% ultrafine magnetite (Fe3O4) particles dispersed with surfactants in water or kerosene were used. The DSC was operated with the optimum heating rate (10 K . min- 1 ) and with equal heat capacities of sample and standard materials in the temperature range, 295 to 345 K. Synthetic sapphire (a-Al2O3) was used as the standard reference material, and the sample pan was made from aluminum. The differences between the measured specific heat capacity values of pure water and pure copper and the recommended values were within +3 and ±1%, respectively. The specific heat capacity data of magnetic fluids showed weak temperature dependence, but strong concentration dependence. The measured values of specific heat capacity of magnetic fluids were compared with calculated values using a mixing rule.