Feni-magnetic Temperature Compensation Alloy

Magnetic temperature compensation alloys are widely used in permanent magnetic circuit for stabilizing the magnetic flux in the air-gap. In this thesis the magnetic temperature alloys used in temperature range from room temperature to 160℃, were prepared by vacuum melting. The influences of doping and heat treatment on the magnetic temperature performances of the alloys were systematically investigated. The best doping compositions and the best heat treatment parameters were obtained. Finally, the temperature compensation characteristics of the alloys were verified experimentally in the SmCo magnetic circuit and by the finite element simulations.Fe64Ni36 magnetic temperature compensation alloy was prepared by vacuum melting technique. The influences of doping elements Mn, Cr, Mo and Co on the properties of the alloys were investigated. The results show that both the working magnetic flux density Bm and the curie temperature Tc decrease monotonously with the increase of the content of the doping nonferromagnetic elements of Mn, Cr and Mo. The variation of the magnetic flux density with the temperature△B_m /△T decreases with the increase of the doping content. It is also observed that the Bm and the Tc of Fe64Ni36 alloy are not influenced by the Co element doping. In this thesis , the best doping elements and content are Mn2wt%,Mn3wt% and Cr3wt%.Several kinds of magnetic temperature compensation alloys with good magnetic temperature performances were annealed, and the effect of annealing temperature and annealing time on the magnetic temperature properties of the alloys were studied. The results show that high annealing temperature can improve the Bm and△B_m /△T. The annealing time has little influence on the magnetic temperature performances. The Curie temperatures of alloys are not dependent on the vacuum annealing. The best annealing process parameter is 500℃for 2 hours in this thesis.The influences of the temperature on the magnetic flux density of a point P in the air-gap of the SmCo magnetic circuit including the magnetic temperature compensation alloys were simulated with the ANSYS finite element software. Experimentally, the magnetic temperature compensation properties of the alloys were verified in the SmCo magnetic circuit. The experimental results are agreement with the simulation results qualitatively. The results shows that with the application of magnetic temperature compensation alloy, the change rate of magnetic flux density of the point P varied from -0.029 mT/℃to 0.004 mT/℃in the temperature range of 20℃to 160℃. This indicates that the magnetic temperature compensation alloy has an excellent compensation effect. The results also show that the compensation effect of magnetic temperature alloy depends intimately on the sectional area of the alloy. Small sectional area results in inadequate compensation, and large sectional area results in excessive compensation.