The Effect Of Multiple Microelements On The FeNiPB Series Ultra-Fine Soft Magnetic Materials

Orthogonal experiments are carried out to investigate the effect of Cu and Nb binary microelements on the structures and magnetic properties of FeNiPB series alloys. Fe_65-x-yNi₁₅Cu_xNb_yP₁₄B₆ (x=0.5,1,1.5;y=1,2,3) amorphous powders are fabricated by mechanical alloying. Nanocrystalline magnetic rings could be obtained after subsequent pressing and certain heat treatments.A theoretical model is proposed to explain the effect of Cu and Nb microelements on the crystallization of FeNiPB series amorphous magnetic rings. The model shows that the small addition of element Cu could lead to the componential asymmetry of amorphous base before the crystallization, large numbers of fine Fe-rich clusters emerge dispersively on the amorphous base, more nucleant cores ofα-Fe grains tent to come out in these areas. Meanwhile the existence of microelement Nb could restrain the growth of the grains due to its lager atomic size during the crystallization of amorphous alloy. A special microstructure with nanosizedα-Fe grains dispersing on the amorphous base is formed under the co-operation of the additions of Cu and Nb microelements.The results show that when the ratio of relative additions of Cu and Nb microelements equals 1:2, better results of crystallization for FeNi(Cu,Nb)PB amorphous alloys could be acquired, in the meantime better soft magnetic properties could also been achieved for these samples.Similar measures are used to study the effect of Al, Cu and Nb ternary microelements on the structures and magnetic properties of Fe_62-zNi₁₅Al_z Cu₁Nb₂P₁₄B₆ (z=1,2,4,8) nanocrystalline magnetic alloys. The results show that small additions of element Al will promote the growth ofα-Fe grains, Accomplished with the increasing of Al content, the permeability of the magnetic rings will decrease while the coercivity of the FeNi(Al,Cu,Nb)PB alloys will first increase, then decrease and reach the top when the content of Al equals 4%. When 2% of Al are added into the FeNi(Al,Cu,Nb)PB alloys, it is hopefully that these materials will turn into good rectangular magnetic materials.The influence of technical factors on the magnetic properties of FeNiPB series materials are discussed in this article. It shows in the experiments that preventing the oxidation of powders during the fabricating processes, achieving higher density of the magnetic rings and applying appropriate heat treatments are the most critical factors in improving the magnetic properties for these nanocrystalline soft magnetic materials.