Tm(Ⅲ)在氯化物熔体中电还原的研究

用循环伏安法、恒电位电解及断电后的电极电位—时间曲线、Ｘ射线衍射法研究ＮａＣｌＫＣｌＴｍＣｌ３熔体中Ｔｍ（Ⅲ）在铁、钴、镍、铜等阴极上还原的电极过程。在这些金属阴极上首先形成合金，然后才析出金属铥。

尿素熔体中镧钴电解共沉积的研究

采用循环伏安曲线、电子探针、Ｘ射线衍射法，研究了尿素－ＮａＣｌ－ＮａＡｃ－ＣｏＣｌ２－ＬａＣｌ３熔体中镧钴电解共沉积。阴极电位、电流密度、熔体中Ｌａ３＋／Ｃｏ２＋摩尔比以及电极基体均影响沉积物中的含镧量。沉积物由Ｃｏ和Ｌａ组成，两者并未形成金属间化合物。

阳极氧化铝在KMnO_4-H_2SO_4溶液中电解着色机理的研究

本文用循环伏安曲线、李沙育图形及电子探针等方法探讨了阳极氧化铝在KMnO_4-H_2SO_4体系中的着色行为,提出了着色是通过电化学反应产生的吸附氢还原MnO_4^-为MnSO_4与MnO_2混晶所引起的.同时还考查了溶液酸度、高锰酸钾浓度、着色电压、叠加直流电压等因素对着色效果的影响.

在尿素熔体-NaBr-KBr中Nd-Co, Tb-Co和Yb-Co的电沉积(英文)

稀土－钴合金因其具有磁性和磁光性等功能而为人们所关注．在有机溶剂电解液中，报道过的稀土－钴合金的电镀只有电镀Gd－Co和Sin－Co膜．在我们从尿素－金属氯化物熔体中获得La－Co电沉积物以前，未见在低温熔体中电沉积稀土－钴合金的研究报道．尿素（79mol％）－NaBr（19．5mol％）－KBr（1.5mol％）的熔点为51℃，可在100℃左右作为本底熔体，用于电解，本文研究在100℃的尿素－NaBr－KBr熔体中钴分别与钛、铽、镱的电解共沉积.测定循环伏安曲线获知Co2＋还原为Co是一步不可逆过程，加入NaOAc使Co的析出电位负移，因而可能有细化沉积物晶粒的作用．NaOAc的加入量较大时，还可使体系的熔点降低，Nd3＋、Tb3＋、Yb3＋还原为金属的电位很负，因此不能单独析出．但熔体中存在Co2＋时，却可诱导这几个稀土与钴共沉积，电解结果表明沉积物中Nd、Tb、Yb的含量随电位向负方移动而增加．在熔体中含有NaOAc，阴极电位为－1．0V时，电沉积的Nd－Co中含54．86wt％Nd，Tb－Co中含60．06wt％Tb，Yb－Co中含31．53wt％Yb．当熔体不含NaOAc时，稀土－钴沉积物的稀土含量增加．例如阴极电位为－1．0V在无NaOAc熔体中沉积的Yb－Co含Yb增加到55．04wt％．上述结果未见文献报道．

尿素－NaBr－KBr熔体中钴及稀土－钴的电沉积

稀土－钴合金具有许多优异性能，可用于制作磁性、磁光…等功能材料。日本学者研究了在有机电解液中电沉积Ｃｏ－Ｇｄ薄膜，未见前人研究低温熔盐体系中电沉积稀土合金的报道。尿素－（７９ｍｏｌ％）－ＮａＢｒ（１９．５ｍｏｌ％）－ＫＢｒ（１．５ｍｏｌ％）的熔点为５１℃，可在１００℃左右下作为电解介质。在尿素熔体中加入ＢａＯＡｃ，能增加Ｃｏ￣（２＋）还原为Ｃｏ的阴极极化。因此选择１００℃的尿素－ＮａＢｒ－ＫＢｒ－ＮａＯＡｃ作为本底熔体，研究Ｃｏ￣（２＋）的电还原，镧、铽、镝、铥各自与钴的电解共沉积。在所研究的熔体中，Ｃｏ￣（２＋）一步不可逆还原为Ｃｏ。测定Ｃｏ￣（２＋）＋２ｅ＝Ｃｏ反应的传递系数α为０．４５，Ｃｏ￣（２＋）在熔体中的扩散系数为２．５×１０￣（－６）ｃｍ￣２·ｓ￣（－１）。稀土离子还原为稀土金属的电位很负，以致在本底熔体分解前未出现阴极波。但在含ＣＯＣｌ＿２熔体中加入ＲＥＣ＿３（ＬａＣｌ＿３、ＴｂＣｌ＿３、ＤｙＣｌ＿３、ＴｍＣｌ＿３），使钴的析出电位向正方移动，而且阴极电流增大，因而有可能发生ＲＥ（Ｌａ、Ｔｂ、Ｄｙ、Ｔｍ）与Ｃｏ的诱导共沉积。在尿素－ＮａＢｒ－ＫＢｒ－ＮａＯＡｃ－ＣｏＣｌ＿２－ＲＥＣｌ＿３熔体?

非水系中钴和镧钴合金的电沉积

研究了在含Ｃｏ（Ⅱ）或含Ｃｏ（Ⅱ）＋Ｌａ（Ⅲ）的尿素－ＮａＢｒ－ＫＢｒ－甲酰胺体系中钴和镧钴合金的电沉积过程。测定了该体系中电极反应Ｃｏ（Ⅱ）十２ｅ＝Ｃｏ的传递系数及ＣＯ（Ⅱ）的扩散系数。在铜基体上得到含镧达５０Ｗｔ％的镧钴合金电沉积层。

氯化物熔体中钇的电还原和合金化

用循环伏安法研究ＮａＣｌ—ＫＣｌ—ＹＣｌ＿３，熔体中Ｙ￣（３＋）在钨电极上的电还原。Ｙ￣（３＋）一步可逆电沉积为钇。用循环伏安法、卷积伏安法、恒电位电解断电后的电位－时间曲线及Ｘ射线衍射法研究了Ｙ￣（３＋）在铁电极上的还原过程。在金属钇析出前，电极形成多种钇与铁的金属间化合物。用电位阶跃的电流－时间曲线测定了钇在Ｙ＿６Ｆｅ＿（２３）相中的扩散系数及扩散活化能，结果表明钇在其合金相中的扩散相当缓慢，该步骤对电极过程可能起控制作用。

铥离子在氯化物熔体中还原的电化学行为

用循环伏安法、恒电位电解断电后的电位一时间曲线及Ｘ射线衍射法研究Ｔｍ３＋在氯化物熔体中还原的电极过程。在Ｗ，Ｍｏ电极上Ｔｍ３＋首先还原为Ｔｍ２＋，然后析出金属Ｔｍ．在Ｎｉ电极上形成Ｔｍ－Ｎｉ合金后才析出金属Ｔｍ测定了Ｔｍ３＋在氯化物熔体中的扩散系数及扩散活化能，得到１ｎＤ＝－４．３５－５８．２×１０３／ＲＴ．

Studies on Electrolytic Codeposition of Lanthanum-Cobalt in Urea Melt

The electrolytic codeposition of lanthanum-cobalt in the melt consisting of urea-NaCl-NaAc-CoCl2-LaCl3 was studied by means of cyclic voltammetry, electron probe analyser, X-ray diffraction. Cathodic potential, current density, La3+/Co2+ molar ratio in the melt and the electrode substrates all exercise influence on the content of lanthanum deposied. The deposites consist of cobalt and lanthanum, but they don't form any intermetallic compound.

Electroreduction of Co(Ⅱ) and La(Ⅲ)in UreaMelt

Electroreduction of Co(Ⅱ)to metallic cohalt in urea melt is irrevsible in one step.The transfer coeffi-cient of electrode reaction of Co(Ⅱ)+2e=Co(O)and the diffusion coefficient of Co(Ⅱ)were determined.The lanthanum can be inductively codeposited with cobalt. The contents of lanthanum in cobalt-lanthanum de-posts increase with the shift of electrode potential to the negative direction and the raise of La(Ⅲ)/Co(Ⅱ)mo-lar ratio in the melt. The cyclic voltammetry,open circuit potential-time curve after potentiostatic electrolysisand electron probe analyas were used.

Electroreduction of Y(Ⅲ)in Molten Chlorides and Alloying

The electroreduction of Y(Ⅲ)on tungsten electrode in NaCl-KCl-YCl_3 melt has been investi- gated by cyclic voltammetry.Deposition of Y(Ⅲ)to Y(0)is reversible in one step.The cyclic voltammetry, convolution voltammetry,potential-time curve after potentiostatic electrolysis and X-ray diffraction analy- sis were used to study the electrode process of Y(Ⅲ)reduced on iron electrode.Several Y-Fe intermetallic compounds are formed before the deposition of metallic yttrium.The diffusion coefficient and diffusion activation energy of Y in Y_6Fe_(23) were determined by current-time curve at potential step. The results indicate the diffusion of Y in its alloy phase is so slow that this step will control the electrode pro- cess.

Preparation of Rarc Earth Alloys by Cathodic Alloying

The electrode processes of La(Ⅲ), Ce(Ⅲ), Pr(Ⅲ), Nd(Ⅲ) and Y(Ⅲ) reduced on iron, cobalt, nickel andcopper electrodes in chloride melts were investigated by cyclic voltammetry, potential- time curve afterpotentiostatic electrolysis and current-time curve at potential step. The diffusion coefficient of deposited metalatom in the alloyed cathode and the free energy of formation of intermetallic compound were determined.Thirteen surface alloy layers were obtained by electrolysis at constant potential. The alloys of La-Fe, La-Ni,La-Cu, Pr-Fc, Pr-Co. Pr-Ni. Pr-Cu, Nd-Fe, … were prepared by consumpable cathode.