模压电感用软磁材料的绝缘阻抗失效原因研究

探讨了模压电感在低温烘烤后绝缘阻抗突变的原因,并试图找到改善绝缘阻抗的方法。研究发现,金属软磁粉末及其包覆层之间的表面结合力随着温度升高先升高后降低,且该包覆层物质随着温度的升高而脆化。证明绝缘阻抗突变的原因在于包覆层物质在固化过程中的体积变化和固化产物引起表面结合力的变化,且固化程度越高,包覆层越脆,二者相互作用后使得包覆层产生剥皮甚至脱落,从而造成模压电感在烘烤后绝缘阻抗失效。

Study on the failure cause of insulation resistance of soft magnetic materials for molded inductors

The reasons for the change of insulation resistance of molded inductor after low temperature baking were discussed,and the method to improve the insulation resistance was tried to found. It is found that the surface bonding strength between the metal soft magnetic powder and the coating layer increases firstly and then decreases with the increase of temperature,and the coating layer becomes brittle with the increase of temperature. The re-sults show that the reason for the change of insulation resistance is that the volume change of the coating material in the curing process and the change of the surface bonding strength caused by the curing product,and the coating layer is more brittle with the higher curing degree,and the interaction between the two causes the coating layer to produce peeling or even peeling off,which results in the insulation resistance failure after baking.