自形成CoFe_2O_4磁性液体的热效率

Heating rate of self-formed CoFe_2O_4 magnetic fluids

采用化学共沉淀法制备了自形成CoFe_2O_4磁性液体,对颗粒进行了表征并测量了磁性液体物理性能参数。分析了自形成CoFe_2O_4磁性液体的弛豫特性。研究了自形成CoFe_2O_4磁性液体的热效率与磁性液体粒径关系、热效率与磁场频率的关系,并与表面活性剂型CoFe_2O_4磁性液体进行了比较。其结果表明,在体积分数相同的情况下,用最可几粒径近似的单分散体系热效率比多分散体系的平均热效率高;当体积分数?=0.071时,正十四碳烷基单分散体系表面活性剂型CoFe_2O_4磁性液体的最大热效率与水基自形成单分散体系CoFe_2O_4磁性液体的热效率基本一致。

In this paper, self-formed CoFe2 O4 magnetic fluids are prepared by chemical co-precipitation method. The characterization and the basement physical properties parameters of magnetic fluids are obtained. The relax-ation characterizations of self-formed CoFe2 O4 magnetic fluids are analyzed by magneto-thermal power dissipa-tion theory. The relationships between heating rate and radius of self-formed CoFe2O4 magnetic fluids, and heating rate and frequency under different magnetic field are obtained. It shows that the number of heating rate of the most probable size approximated monodisperse system are bigger than average heating rate of polydisper-se system at the same volume fraction. The tetradecane-based and self-formed magnetic fluids have basically the same heating rate at volume fraction Ф = 0.071.