The Effect Of Soft Magnetic Properyies With New Types Of Inorganic Binder Used In Powder Core

The preparation method of powder cores is of the preparation of powder cores powder, powder insulation, pressing molding and annealing steps. Binder is needed in the pressing step. Now in the actual production the binder which is mostly used comprises an inorganic binder and an organic binder. The organic binder is usually resins, such as epoxy resin, phenol resin, and so on. Adding an organic binder is conducive to the powder cores pressing, molding density. With the development of power industry, the requirements of the switching power supply is small, and raising powder cores forming density is conducive to increase the saturation magnetization per unit volume, allowing the device to the miniaturization. Powder cores’ annealing temperature is not high with an organic binder added, so it can’t effectively release the residual stress in the press-molding process. This will lead to coercive force of the powder cores increasing, and the power loss increasing as well. Therefore, the inorganic binder can effectively solve the above problems caused by an organic binder. With an inorganic binder added annealing temperature of the powder cores is usually higher,and it effectively release the stress caused by the tremendous pressure of the pressing process, thereby reduce the coercive force, and reduce the hysteresis loss. In addition, the inorganic binder can effectively increase the resistance of the grain boundary and reduce the eddy current loss. Sodium silicate, calcium carbonate, alumina, boric acid compound as a raw material, in accordance with certain components are made of new inorganic binder mixed after milling. Powder cores made of Fe85Si9.4Al5.6alloy powder as a adding a new inorganic binder and pressed molding are annealed in a nitrogen atmosphere for sintering. After the measurement and analysis of the various parameters of the magnetic powder core such as strength of the sample loop, the inductance value, the permeability rate, Q value,and the power loss, powder cores sample added an inorganic binder exhibit excellent soft magnetic properties。In25℃, when the100mT measuring magnetic powder core power loss, powder cores sample with the inorganic binder mass fraction of0.75%added, powder cores sample loop lowest power loss,50kHz only167.6KW/m33; in125℃, measured100mT magnetic powder core power loss, add the the inorganic adhesive powder cores sample loop, the mass fraction of the inorganic binder,0.75%, and magnetic core the sample loop power loss minimum at50kHzwhen only283.3KW/m3;...