Microstructure And Magnetic Properties Of MnAl Based Permanent Magnetic Materials Doped With Non-magnetic Elements

Rare earth permanent magnets have excellent magnetic properties.However,in recent years,with the decrease of rare earth reserves,the cost of rare earth permanent magnets increases.MnAl permanent magnet is regarded as one of the promising candidates because of its excellent magnetic properties and low cost.But,the ?-phase MnAl permanent magnet is easily decomposed.Therefore,the aim of the study is to obtain MnAl permanent magnet with stable structure.The purpose of the paper is to study the effects of doping X elements(X=Zr,C,Cu)into the MnAl pennanent magnet by structural calculation and experimental synthesis.The research conclusions are as follows:Structural calculation:MnAlX(X=Zr,Cu)'s state density of spin up and spin down is asymmetric,which indicates that MnAlX(X=Zr,Cu)has strong magnetism.In MnAlX(X=Zr,Cu),with the increase of Zr content,the total magnetic moment of the crystal decreases gradually,while with the increase of Cu content,the total magnetic moment of the crystal increases gradually.Experimental synthesis:In Mn50+yAl50-x-yZrx(x=1?4,y=0,1,3,4),the increase of Zr content is beneficial to the magnetic ? stabilization and the decrease of ?2.Mn51Al45Zr4 has the highest coercivity,3.37 kOe at room temperature,and the maximum saturation magnetization,97.47 emu/g.Mn50Al50-xZrxCz(x=1?4,z=3,1.7)series alloy samples have lower saturation magnetization and higher coercivity than Mn50+yAl50-x-yZrx(x=1?4,y=0,1,3,4)samples,of which Mn50Al46Zr4C3 has the highest coercivity,3.69 kOe.Mn50Al47Zr3 is used for ball milling with different time.The coercivity of the sample with the time is first increase,then the change trend of decrease.The coercivity increases due to grain refinement.The coercivity decreases due to amorphzation in the samples.The remanence of Mn50Al50-xZrxC1.7/Fe(x=2,4)increases.The coercivity of Mn50Al50-xZrxCu/Fe(x=2,4)increases by annealing half an hour at 500?.