Composition Design And Soft Magnetic Properties Of Co-Based Amorphous Alloys

In recent years,fluxgate sensors have been applied in various fields of weak magnetic field detection such as geological exploration,petroleum logging,magnetic navigation and magnetic material testing.As a new functional material,amorphous alloy is widely used in fluxgate sensors.Fluxgate is built on the physical basis of hysteresis loop.The performance of fluxgate sensors fundamentally depends on the magnetic effect of magnetic core materials.Co based amorphous alloy not only has good mechanical properties,but also has excellent soft magnetic properties,such as very high permeability,low coercivity and high saturation magnetic induction,is an excellent choice for the preparation of fluxgate sensor core materials.In this paper,the Co-Fe-Si-B base alloy system with excellent magnetic properties is taken as the research object,and the soft magnetic properties are further improved by doping ferromagnetic elements Cr and Ni,adjusting the strip preparation process parameters and annealing process parameters.In order to obtain amorphous strips that meet the magnetic core requirements of fluxgate sensors,the main research contents and results of this paper are as follows:（1）The Co_64.25Fe_5.35Cr_4.9Si_16.5B₉and Co₆₇Fe₄Ni₇Si₈B₁₄two combination amorphous forming ability and the performance of the soft magnetic differences was studied,the results show that the Co₆₇Fe₄Ni₇Si₈B₁₄alloy has better amorphous forming ability and thermal stability,The supercooled liquid phaseΔT_xis 96 K.Co_64.25Fe_5.35Cr_4.9Si_16.5B₉show more excellent soft magnetic properties and its permeability is 168.64 k,coercive force is 0.461 A/m,saturated magnetic induction intensity is 362 m T.（2）The width is 0.5 mm,thickness of 20 to 30 microns Co_64.25Fe_5.35Cr_4.9Si_16.5B₉,Co₆₇Fe₄Ni₇Si₈B₁₄alloy strips were prepared by single roll sling method,strips evenly over the surface of metallic luster.The effects of different roll speeds on the soft magnetic properties of two gold belts were studied.Results show that with the loss of the roll speed,the combination of the two metal bar with soft magnetic properties are improved,the roller speed when the 20 m/s Co_64.25Fe_5.35Cr_4.9Si_16.5B₉magnetic can stand out.（3）For the above has the best magnetic stripe vacuum constant temperature annealing treatment,study the different annealing temperature,heating rate,holding time on Co_64.25Fe_5.35Cr_4.9Si_16.5B₉amorphous soft magnetic alloy strip.The results show that the alloy strip always presents an amorphous structure at the annealing temperature of 377-467℃and the heating rate of 30-60℃/min,and its magnetic loss P_sdecreases monotonically with the increase of annealing temperature.Under the annealing process parameters of 437℃annealing temperature,40℃heating rate and 60 min holding time,the optimal magnetic properties were obtained,the initial permeability was 221.8 k,the maximum permeability was 1011.4 k,the saturation magnetic induction was 412.6 mT and the coercivity was 0.2 A/m.