The precursor prepared by coordinated co-precipitation was direct reduced by hydrogen to ultra-fine fibrous Fe-Ni alloy powder.The effects of concentrations of reactants,pH value,reaction temperature and additive on the preparation of precursor were systematically investigated.The structures,thermal decomposition processes and morphologies of the precursors were characterized by X-ray diffraction(XRD),thermal gravity-differential thermal analysis(TG-DTA)and scanning electron microscoy(SEM).The results show that using 2％ polyvinylpyrrolidone(PVP)(in mass fraction)as additive,a well-dispersed precursor with a uniform morphology can be obtained in a solution with Fe2+ and Ni2+ total concentration(1:1)of 0.8 mol/L,pH value of 6.2 at 60 ℃,and a pure and well dispersed fibrous iron-nickel powder can be prepared by direct reduction of this precursor in a mixed atmosphere of nitrogen and hydrogen at the temperature of 420 ℃.%采用配位共沉淀制备了铁镍合金前驱体,用氢气直接还原前驱体得到了超细纤维状铁镍合金粉.系统研究了反应物浓度、pH值、反应温度及添加剂等参数对前驱体制备过程的影响.分别采用XRD、TG-DTA和SEM对前驱体的结构、热分解过程和形貌进行了表征.结果表明,采用质量分数2％的PVP作为添加剂,当Fe2+和Ni2+(1:1)总浓度为0.8 mol/L,pH值为6.2,反应温度为60℃时,可以制得分散良好、形貌均匀的纤维状前驱体.前驱体在4200℃的氮气和氢气混合气氛下直接还原可以得到纯度高、分散性好的纤维状铁镍合金粉.
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