Affecting Factors Study On The Magnetic Properties Of 1J85 Soft Magnetic Alloy

As the main materials of information transformation or electromagnetic shielding device,1J85 soft magnetic permalloy are worked in AC weak magnetic field.Stable microstrucrure,high resistance to external magnetic disturbance ability and high soft magnetic properties are absolutely necessary according to working conditions.Magnetic property of 1J85 alloy produced in China were imitated from PC-80 alloy in Japan,which have the basic magnetic properties meet the national standard and customer's requirements but is somewhat not high enough compared with those from some foreign manufacturers,especially for initial permeability and coercive force.So it is crucial to improve the magnetic properties and market competitiveness of 1J85 permalloy through analyzing possible factors and mechanism which affect magnetic property,and proposing some processing measures for1J85 alloy from the above company subsequently.In this paper,1J85 perm alloy strip of 0.1mm thickness made from two different domastic manufacturers and a foreign manufacturer were selected as research object.The affecting factors and the influence rule of composition,purity,and structure and grain size on the magnetic properties of1J85 alloy were investigated.The types of non-metallic inclusions were discussed by means of thermodynamic calculation followed by experimental verification,and influence mechanism of non-metallic inclusions and microstructure on the magnetic properties of 1J85 alloy were analyzed,followed by explorative experiment of non-metallic inclusion modification.The main research conclusions are as follows:(1)According to the modified magnetic atomic ratio theory on high permeability alloy,the suitable alloy composition may be Ni_80.1Cr_0.5Mo_5.2Mn_0.5Al_0.15Si_0.23 only considered the?_i?100m H·m^-1case,while suitable alloy composition may be Ni_80.60Mo_4.83considered both?i?40m H·m^-1and Bs?0.8 T case;(2)Thermodynamic calculation and experimental research showed that the possible non-metallic inclusion phases formed in 1J85 alloy were Al₂O₃,Al₆Si₂O₁₃,Mn₃Al₂Si₃O₁₂and Mg O-Fe O-Ca O multiple oxides combined with small amount of Fe S and Mn S which can be divided into spinel inclusions,mono sulphide inclusions,and sulfur-oxide compound inclusion,The proportion of magnesia alumina spinel based on alumina are high for domastic samples that is harmful magnetic properties;while the proportion of sulfur-oxide compound inclusions are high for forign samples,which is benefit to improve magnetic properties.(3)It can be seen that magnetic properties of 1J85 alloy are deteriorated as the amount of non-metallic inclusions increasing especially when the size equal to or less than 1?m.Due to the size of the inclusions are closed to magnetic domain size,demagnetizing field may form the new mixed and disorderly magnetic domain structure of magnetic field,which may resistant the magnetic domain wall movement,as a result lead to deteriorated magnetic properties.(4)Large grain size is benefit to improve magnetic properties.With growth of grain fineness number from 2.5 to 4.5(grain size 151?m to 75.5?m),the?_oof 1J85 alloy decreased from 280.9m H·m^-1to 71m H·m^-1,the?_mfrom 858.3m H·m^-1to265 m H·m^-1,H_cincrease from 0.417A·m^-1to 0.9A·m^-1due to less pinning of domain wall displacement.Prolonging annealing time contribute to increase grain size.Influence factors affect magnetic properties were obtained by means of thermodynamic calculation and experimental research.And some feasible process improvement measures were proposed subsequently.