Structure and Magnetic Properties of Co-Zr Alloys

Structure and Magnetic Properties of Co-Zr Alloys
　　Magnetic materials occupies important position in society in the nowadays , catch hitherto unknown attention right away once third generation rare earth permanent magnetism Nd-Fe-B appearing in the market,proprietor’s making joint efforts also makes development of Nd-Fe-B series permanent magnetism very swift and violent , very quick, and the function using latent energy one empty space to be enearth, changeable function difficulty continuing improving Nd-Fe-B , self contain abuse of rare earth easy to oxidize also being difficult to solve more well. People starts appearing that hopes in another one kind of much better permanent magnetic materials.Co-Zr base the series alloy is beginning to study in 1964, the initial stage it is exceeded high anisotropy field above metal neodymium magnets permanent magnetic materials, quickness quenches material having very good suppleness , this is that reality very suitable applies a characteristic of the Co-Zr base series alloy. People are discovered, Co-Zr base series alloy hard magnetism properties is controlled by Co5Zr phase , this one phase finds that on 1986 by Z.Altounian first in amorphous alloy, Co5Zr phase has fcc structure, space group F43m or F23 , crystal lattice constant a = 6.7A; ,
　　Curie temperature Tc=500℃. Often, the existence has fcc Co phase, Co11Zr2 phase and Co23Zr6 phase in Co-Zr base alloy. in Nature fcc Co only stabilize existence in all above 425℃, but it can be discover often all various smelting and quenching quickly in Co-Zr series alloy.Co11Zr2. Co11Zr2 phase has Pcna space group orthogonality crystal structure, crystal lattice constant a = 4.8A,b = 8.2A,c = 36A ,Curie temperature 490℃. Co23Zr6 phase has fcc structure,space group Fm3m, crystal lattice constant a=11.56A. A important condition having uniaxial anisotropy, being that magnetic materials is able to apply.We have studied the Co80+xZr20-x(0≤x≤4)alloy structure and magnetism properties:Co80+xZr20-x(0≤x≤4)smelting alloys have taking form rough crystal structure by arc stove. Most probably, smelting alloy middle mainly contains fcc Co phase, Co5Zr phase two kinds from the X-ray diffraction result having the broad diffraction peak, the broad diffraction peak is in a process changing each other being indicating a sample per se right away , liquid state changes to fcc Co phase, Co5Zr phase from ebullition metal state, crystal particle being are rough by cooled speed effect. Sample has saturation magnetization 71 emu/g , as a result of Co5Zr phase existence. In the smelting sample, rough crystal particle of Co5Zr phasee also pointing out that we, exercise direct heat treatment of smelting sample may become acquisition the Co5Zr compound.Quench the technology progress quickly , make this one handicraft become important means for study of science and production. Speed of melt-spun, to Co80+xZr20-x(0≤x≤4) alloys quench the effect bringing structure and the function along slightly quickly very big.
　　To Co80+xZr20-x(x=1、3、4) alloy, quickness quenches having dried as well as with 40 m/s speed , the Co84Zr16 alloy quickly quenches sample having being amorphism state very well, saturation magnetization intensity 61 emu/g , coercive force 90 Oe , magnetic moment per atom 1.10μB. Electric charge between Co atom 3d energy bands and Zr atom metastasis.Co80+xZr20-x(x=0、2) alloys with 25m/s speed melt-spun quickness quenches strip, manily have fcc Co and Co5Zr phase structure, have approximately 0.5 kOe coercive force, it totally different from alloys strip with 25m/s speed melt-spun quickness quenches. With the increase of Zr content x in the Co-Zr alloys, coercive force increase, saturation magnetization intensity increase, magnetic moment per atom increase, content of the Co5Zr phase also increases in melt-spun quickness quenches http://www.chinamagnets.biz/ Co-Zr alloys. Therefore, continued changing the alloy component and melt-spun speed, be able to obtain Co5Zr compounds and more good magnetism properties , it opens up a road to clearer know characterof the Co5Zr compound.Heat treatment Co80+xZr20-x(x=1、3、4) alloys, that melt-spun with 40 m/s speed, the heat treatment temperature is 550℃, 650℃, 750℃, heat treatment time is 2 hours. Sample after heat treatment, saturation magnetize intensity and magnetic moment per atom increase with the heat treatment temperature enhance. X-ray diffraction result of heat treatment Co81Zr19 quickness quenches strip point out that, fcc Co occupies main position, and a few Co23Zr6 phase, and with the heat treatment temperature increase, crystal spend gradually changeable completeness. Therefore, fcc Co appearing, is playing decisive role to the magnetism of quickness quenches alloys, crystal is spent gradually perfect, the crystal particle growth has produced effect also to magnetism. Electricity mirror result demonstrates , the strain of quickness quenches alloys has effect and inhibitory action to the crystal particle growth certain.In sum, we have known hard magnetism phase——Co5Zr phase can come true by two kinds approach in Co-Zr alloy, this have provided for this gaining the Co5Zr compound to facilitate. Various clear cognition Co5Zr compound physical property, further improve Co-Zr series alloy magnetism.