流体静高压原位磁测量的误差研究(二)──退磁场的影响

A DISCUSSION ON THE ERRORS FOR THE IN SITU MAGNETIC MEASUREMENTS IN HYDROSTATIC HIGH PRESSURE VESSEL

为了探讨流体静高压原位磁测量中退磁场的影响有多大？分别选用６种不同片数（ｎ＝１、３、５、７、１０、１３）的非晶Ｆｅ４６．３Ｃｏ０．０３Ｎｉ４６．５Ｓｉ３．７５Ｖ０．９２Ｂ２．５合金薄带样品，先后放进１３层密绕直螺线管初级线圈内，采用工业频率４００Ｈｚ去测量和比较其磁化曲线、磁导率曲线和起始磁化曲线。研究表明：（１）样品片数越多，退磁场的影响越大，导致μｍ和μｉ出现惊人的测量误差，以１片（μｍ＝４４３０，μｉ＝３３９６）为最准。（２）随着样品片数的增多，测量饱和磁感应强度Ｂｓ＝０．８３７～０．７６２Ｔ，表明受退磁场影响较小。（３）若要减小退磁场误差，可将样品做得更薄，如０．２μｍ薄膜。（４）若要彻底消除退磁场误差，必须采用闭合磁路，如用非晶合金薄带卷成的圆环。

To study the influence of demagnetic field in the hydrostatic high pressure vessel,we selected 6 samples with different slice number ( n =1,3,5,7,10,13) of amorphous alloy Fe 46.3 Co 0.03 Ni 46.5 ·Si 3.75 V 0.92 B 2.5 ribbon,inserted them into multiple electric solenoid and measured the magnetization,magnetic permeability and initial magnetization,respectively,at 400Hz.We found that:(1) The more the slices of sample,the stronger the influence of demagnetic field was,which leaded in surprising errors of μ m and μ i.For the sample with 1 slice,we obtained the optimal values, μ m=4430, μ i=3396.(2) With the increase of slice number ( n =1～13),we measured saturation magnetic induction B s=0.837～0.762T,indicating the influence of demagnetic field on B s was much small.(3) To reduce the error from demagnetic field,thinner sample could be used,for example thin film with 0.2μm thick.(4) To eliminate the error from demagnetic field,closed magnetic circuit must be adopted,such as ring rolled up by amorphous alloy ribbon.