Abstract: Provided is a surface treatment method of metal powder and surface passivated metal powder. Herein, the surface treatment method uses passivation solution to treat the metal powder, to form a passivation film on the surface of the metal powder; the passivation solution passes through the metal powder by a flowing method; and the average particle size of the metal powder is 0.1˜100 ?m. A problem in the prior art that the metal powder is easily oxidized is solved, and it is suitable for the field of metal anti-oxidation.

Abstract: The present disclosure provides a rare earth ion-doped soft magnetic alloy, a soft magnetic composite material and a preparation method thereof. The rare earth ion-doped soft magnetic alloy is composed of Fe, Si, Al, N and Re, and the Re is a rare earth element; and herein, in the rare earth ion-doped soft magnetic alloy, the content of the Fe is 82-85 wt %, the content of the Si is 8-10 wt %, the content of the Al is 3-5 wt %, the content of the Re is 1-2 wt %, and the content of the N is 0.25-0.65 wt %. Most of the interior of the rare earth ion-doped soft magnetic alloy of the present disclosure is composed of FeSiAl crystal grains, but an appropriate amount of an easy-faced Re—Fe—N compound is dispersed among the FeSiAl crystal grains. Based on such a structure, the rare earth ion-doped soft magnetic alloy of the present disclosure has excellent electromagnetic properties and lower loss under a working condition of MHz.