Preparation method of phosphoric acid/graphene/silicon nitride coated Fe-Si-Al magnetic powder core

The invention discloses a preparation method of a phosphoric acid/graphene/silicon nitride coated Fe-Si-Al magnetic powder core, and relates to the field of soft magnetic materials and powder surface treatment. The preparation method of the phosphoric acid/graphene/silicon nitride coated Fe-Si-Al magnetic powder core comprises the following steps of powder preparation, phosphoric acid/graphene/silicon nitride coating, lubricant adding, compression molding and annealing. The iron-silicon-aluminum magnetic powder core is compositely coated with phosphoric acid/graphene/silicon nitride, so that the wave absorbing property and the high temperature resistance can be improved, the increase of the loss of the iron-silicon-aluminum magnetic powder core and the reduction of the magnetic conductivity caused by high-temperature treatment and the improvement of the wave absorbing property are effectively avoided, and the service life of the iron-silicon-aluminum magnetic powder core is prolonged under the condition that