Influence of Ni^(2+)/Co^(2+)ratio in electrolyte on morphology,structure and magnetic properties of electrolytically produced Ni-Co alloy powders  

电解液中Ni^(2+)/Co^(2+)比对电解Ni-Co合金粉末形貌、结构和磁学性能的影响

作　　者：Vesna M.MAKSIMOVIC Vladan B.KUSIGERSKI Milovan M.STOILJKOVIC Jelena R.MALETASKIC NebojSa D.NIKOLIC 

机构地区：[1]Institute of Nuclear Sciences,“Vinca”,University of Belgrade,P.O.Box 522,Belgrade 11001,Serbia [2]Laboratory for Advanced Nuclear Energy,Institute of Innovative Research,Tokyo Institute of Technology,2-12-1 Ookayama,Meguro-ku,Tokyo 152-8550,Japan [3]ICTM-Department of Electrochemistry,University of Belgrade,Njegoseva 12,P.O.Box 473,Belgrade 11001,Serbia

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第4期1046-1057,共12页中国有色金属学报（英文版）

基　　金：financially supported by the Ministry of Education,Science and Technological Development of the Republic of Serbia through the Project Nos.Ⅲ45012,172019 andⅢ45015.

摘　　要：Nickel-cobalt(Ni-Co) alloy powders were produced galvanostatically by using sulphate electrolytes with various ratios of Ni2+/Co2+(mole ratios). The morphology, phase structure, chemical composition and magnetic properties were examined by scanning electron microscope(SEM), X-ray diffractometer(XRD), atomic emission spectrometer(AES), and SQUID-based magnetometer, respectively. Morphology of the particles changed from cauliflower-like and dendritic to coral-like and spongy-like ones with increasing Ni2+/Co2+ ratio from 0.25 to 4.0. XRD analysis of the Ni-Co powders revealed that the decrease of Ni2+/Co2+ ratios(the increase of Co content) caused a change of structure from face centered cubic(FCC) obtained for the ratios of 4.0, 1.5 and 0.67 to a mixture of FCC and hexagonal closed-packed(HCP) phases for the ratio of 0.25. The increasing content of nickel led to change of mechanism of electrolysis from irregular(up to 40 wt.% Ni in the electrolytes) to close to equilibrium(between 40 and 60 wt.% Ni in the electrolytes) and anomalous co-deposition(over 60 wt.% Ni in the electrolytes) type. All of the obtained Ni-Co alloy samples behaved as soft magnetic materials while their magnetic parameters showed immediate composition dependence since both coercivity and saturation magnetization almost linearly increased with increase of the Co content.采用恒电流法在具有不同Ni^2+/Co^2+比(摩尔比)的硫酸盐电解液中制备镍钴(Ni-Co)合金粉末。利用扫描电镜(SEM)、X射线衍射仪(XRD)、原子发射光谱仪(AES)和基于SQUID的磁力仪检测粉末的形态、相结构、化学成分和磁学性能。当Ni^2+/Co^2+比从0.25增加到4.0时,颗粒形貌从菜花状和树枝状转变为珊瑚状和海绵状。Ni-Co粉末的XRD分析表明,Ni/Co比降低(Co含量增加)导致结构变化:Ni^2+/Co^2+比为4.0、1.5和0.67时,粉末为面心立方(FCC)结构;Ni/Co比为0.25时,粉末为面心立方(FCC)和六方密堆(HCP)相的混合物。增加电解液中Ni含量导致电解机理发生变化:当电解液中Ni含量低于40%(质量分数)时为不规则共沉积;Ni含量为40%~60%(质量分数)时接近平衡共沉积,Ni含量高于60%(质量分数)时则为异常共沉积。所有获得的Ni-Co合金样品均为软磁材料,其磁性参数显示出直接的成分依赖性,因为矫顽力和饱和磁化强度几乎都随Co含量线性增大。

关 键 词：Ni-Co alloy powders ELECTROLYSIS hydrogen MORPHOLOGY magnetic properties 

分 类 号：TF123.71[冶金工程—粉末冶金]