Preparation And Properties Of P-free Soft Magnetic Fe-based Amorphous Alloys With High Saturation Flux Density

Soft magnetic Fe-based amorphous alloys have been drawing extensive attention due to their high saturation flux density（Bs）,low coercive force（Hc）and short technological process.They are helpful for modern electrical equipment to becoming more energy saving,mininaturized and efficient.Therefor,soft magnetic Fe-based amorphous alloys have been used as core materials in the energy efficent transformer.However,the developed soft magnetic Fe-based amorphous alloys’ Bs need to be improved and most of them contain P element which is easily volatile and reacting with crucible.These problems severely restrict the development of soft magnetic Fe-based amorphous alloys.We investigated the effect of Cu and Co addition on the glass forming abilities,thermal properties and magnetic properties of a base Fe-B-Si-C alloys system without P element.The obtained Fe-based amorphous alloys simutaneously possess large glass forming abilities and good magnetic properties.In addition,we investigate the effect of heat treat temperature on magnetic properties.The thesis consists of following parts mainly:1.The addition of 0.25-1 at.% Cu element effectively enhance glass forming abilities of Fe₈₆B₁₁Si₁C₂ alloy whose critical thickness can reach 35 μm.With the increasement of Cu elenment,the Bs slightly decrease and Hc have little change.The Fe_85.5B₁₁Si₁C₂Cu_0.5 alloy’s critical thickness of ribbon can reach 35 μm.It’s Bs and Hc is 1.62 T and 12.3 A/m respectly.2.The addition of 2.5-7.5% Co element have a little change on glass forming ability of Fe₈₆B₁₁Si₁C₂ alloy.With the increasement of Co element,Bs increase from 1.63 T to 1.82 T.The Fe₈₁Co₅B₁₁Si₁C₂ alloys’ s Bs and Hc is 1.78 T and 12.6 A/m respectly.3.Simutaneous addition of Cu and Co can effectively enhance glass forming ability and significant increase Bs of Fe₈₆B₁₁Si₁C₂ alloy.The Fe_80.5Co5B₁₁Si₁C₂Cu_0.5 alloys can obtain the optimal magnetic properties,whose critical thickness of ribbon can reach 35 μm,Bs and Hc is 1.78 T and 12.6 A/m respectly.4.With the increasement of annealed temperature,the BS of alloys contaning Co element develop.In addition the annealed ribbons have good toughness.