Manganese zinc ferrite material for eddy current type approach switch, film-coated magnetic core and preparing method of manganese zinc ferrite material

The invention relates to a manganese zinc ferrite material for an eddy current type approach switch, a film-coated magnetic core and a preparing method of the manganese zinc ferrite material. The principal component of the manganese zinc ferrite material contains: 51.5-53 mol% of Fe2O3, 24.0-25.0 mol% of Mn3O4 and 20.50-22.5 mol% of ZnO; and the accessory component of the manganese zinc ferrite material contains:0.50-1.00 wt% of nanometer TiO2, 0.30-0.50 wt% of nanometer SiO2, 1.00-1.50 wt% of nanometer CaO, 0.05-0.35 wt% of nanometer Co2O3 and 0.05-0.10 wt% of nanometer SnO2. The manganese zinc ferrite material is made in the oxide method, formed in mold pressing mode, sintered and grinded and then subjected to film coating on the outer surface of the magnetic core, a transition layer is made of chrome, and a target layer is made of palladium. Resistivity of the manganese zinc ferrite material in 1 MHz is that rho>=10 ohmm, relative temperature thermal index of the manganese zinc ferrite material in the temp