Study On Synthesis And Capability Of Cobalt Nano-magnetic Material

Owing to its good function, the cobalt nano-magnetic material was broadly applied in hard quality metal alloy, battery, eternal magnetic material, the diamond tool manufacturing etc. Small particle, good dispersion and stable cobalt nano-magnetic material can remarkably improve its capability. This thesis makes several of novel morphology, well-proportioned particle, good dispersion and good function cobalt nano-magnetic material thought a related research. The property of the cobalt nano-magnetic material was analysed by using of various analysis and characterization methods. The size, dispersion and morphology of cobalt nano-magnetic material was observed by adopting Philip's Cu Ka X-ray Radiation Diffractometer (XRD) to carry on analyse qualitative analysis to the cobalt nano-magnetic material, confirmed composing of physical phase and crystal lattice parameter; by adopting JEOL JSM-6700 F type Field-emission Scanning Electronic Microscope(FESEM) and H-800 type Transmission Electronic Microscope(TEM) to observe; by adopting Superconductive Quantum Interference Device(SQUID) to measure magnetic property of the obtained product.This research took CoCl2 solution as raw material, regulated pH value through NaOH solution, adopted hydrazine monohydrate as reducing agent, under the help of complexing agent to synthesis cobalt nano-magnetic material. Passed the choice of reducing agent, choose complexing agent, and regulate molar ratio of each reactive component, studied the best composition to preparation of cobalt nano-magnetic material, and studied the influence to synthetical craft when the reactive temperature in the process, reactive time, the concentration of reactants and handle behind of the obtained product etc change. The best experiment condition that the research get is reactive time as 2 hours, reactive temperature as 180℃, when the volume ratio of hydrazine hydrate to ethylenediamine was 2:5, the obtained product was flowerlike cobalt crystallite comprised few of swordlike petals radiating from the center, these petals have sharp of point and outstanding of medium stalk line, its length was about 0.5-1.5 um, the width was about 400nm, the thickness was about 100nm, the size of the whole cobalt microlite was about 3 um; But when the volume ratio of hydrazine hydrate to ethylenediamine was 1:1, the morphology and size of the obtained particle took place very big variety, the obtained product was cauliflowerlike cobalt crystallite comprised dozens of flakelike petals radiating from the center, these petals some have sharp of point and some present hexagon, its length was about 0.5-2um, the width was about 1um, the thickness was about 100nm, the size of the whole cobalt microlite had already increased to 7 um. While PVP was substituted for ethylenediamine as complexing agent, well-proportioned particle and good dispersion dendriticlike cobalt nano-magnetic material was obtained.Ethylenediamine played an important function in the formation of 3D flowerlike architecture. Compared with the bulk Co, the coercivity value of 3D flowerlike cobalt nano-magnetic material at room temperature was much enhanced. Moreover, from the measurement results of distinct temperature can see, under 2 K condition, the value of saturation magnetization (Ms) and remnant magnetization(Mr) compared with that of at 300 K condition did not take place obvious variety, but the coercivity(Hc) represented remarkable change, leaped from 103 Oe(300 K) to 227 Oe(2 K), it is obvious that temperature revealed the graveness influence to the coercivity of the obtained product.