Grain boundary engineering of high performance ferrite cores required for high frequency power electronic components

The development of a high performance ferrite material with capability of 1 to 7 MHz 3dB frequency is pursued. The proposed ferrite material consists of MnZn-ferrite particles with a thin coating of NiZn-ferrite. The role of the NiZn-ferrite coating is to suppress eddy currents, by providing an insulating oxide layer at the grain boundary, without significantly reducing the magnetic flux density, permeability, or allowing the possibility of the tunneling effect. Sources of power loss in ferrite cores are analyzed and practical methods for reducing their effect are presented. Materials fabrication techniques include chemical co-precipitation and spin-spray deposition, both of which lend themselves naturally to large scale production. High magnetic flux density (Bs ~ 550 mT) and permeability (µR ~ 500-20,000) of MnZn-ferrite, combined with an optimized microstructure and engineered interface, hold promise in achieving materials properties necessary for the development of power systems required to support next generation T/R modules in AESA and EW systems. The proposed technology represents a possible pathway to achieving size, weight, and cost reductions, along with increased stability and reduced life degradation in future Navy power systems.