| Zinc alloy is provided with excellent mechanical properties, which is usedsatisfactorily in many projects, and has a wide application prospects in the fields ofcomputer, electrical appliances, aviation, aerospace, automotive manufacturing, shipping,chemical industrial electroplating process and so on. At present, the study onelectrochemical behavior of ZnCl2molten salt is still very few at home and abroads. In thispaper, transient electrochemical techniques, such as cyclic voltammetry,chronopotentiometry were used to study the electrochemical process and electrochemicalformation mechanism of Zn（ΙΙ）in LiCl-KCl melts. However, the reduction process of Nd（ΙΙΙ）and conditions of Zn（ΙΙ）and Nd（ΙΙΙ）by electrodeposition were investigated inLiCl-KCl-ZnCl2（0.6wt.%）melts. Zn-Nd alloys and Zn-Al-Nd alloys with different phaseshave been prepared by electrochemical deposition. All of this supplied a new reliabletechnical routine for Zn-Al-Nd alloy materials.In the first section of this thesis, Zn-Nd alloys were prepared by codeposition methodon an inert electrode in a molten LiCl-KCl-ZnCl2-Nd2O3system. This paper testedrespectively the LiCl-KCl system containing0.6wt.%ZnCl2(j=0.0001mol·cm-3)molybdenum electrode （s=0.5649cm2） at460℃、500℃、540℃and580℃by cyclicvoltammetry, square wave voltammetry, chonopotentiometry to study the reductionmechanism, transport parameters and reversibility properties of zinc ion. The results ofdifferent scanning speeds of cyclic voltammetry curves are: at the scan ranges of10mV·s-1≤v≤100mV·s-1, zinc ion in a molten KCl-LiCl system on molybdenum electrode isirreversible reaction. Through further calculating, it is determined that the zinc ion in thissystem is irreversible. According to one step with two electron transfer, the reduction of zincion proceeded. The test results of the charge transfer coefficient（α） and diffusion coefficientsat460℃、500℃、540℃and580℃are calculated respectively. Then according to AlanArrhenius formula calculated: activation energy EDis4.41×104J·mol-1, diffusion coefficientconstant D0is0.02284×10-6cm2·s-1. The equation of diffusion coefficient changing withtemperature is lnD=-3.7793-5300.31/T.In the second section of this thesis, Zn-Nd alloys were prepared by codepositionmethod on an inert electrode in a molten LiCl-KCl-ZnCl2-Nd2O3system. Firstly, the formation mechanism of Zn-Nd alloy was investigated at molybdenum electrode by cyclicvoltammetry, chonopotentiometry, chronoamperometry and open circuitchronopotentiometry in a molten LiCl-KCl-ZnCl2（0.6wt.%）-Nd2O3（1wt.%） system. Thepotential of zinc cathodic reductive peak was observed at about-1.50V. In the range of-1.2V<sup>-2.0V, the two stable intermetallic formed between of zinc and neodymium. Sampleswere obained by using the constant current electrolytic. XRD analysis method confirmedthat the electrolysis alloy samples contain Nd3Zn11and Nd2Zn17phases. This is because ofthe zinc chloride effect, which makes Zn of Nd happening potential owe sedimentary, andformed metal compounds.The third part of the research is: in LiCl-KCl-ZnCl2-AlF3-Nd2O3system, molybdenumwire served as the cathode and graphite severd as anode, electrolysis deposition to preparezinc-aluminum-neodymium alloy. Through the choice of electrolysis process parameters ofthe current density, the ratio of raw materials, electrode reaction time and so on forexperiment. Though analysising the results of the experiment to found the best preparationprocess conditions: electrolytic temperature is480℃, and the current density is9.55A·cm-2,electrolysis time is2h.This paper studed the zinc ion in LiCl-KCl plasma-nitriding electrochemical behaviorand the electroplating mechanism of the Zn-Nd, Zn-Al-Nd alloy, and provided a method ofmolten salt electrolytic preparation of rare earth aluminum zinc alloy. This is greatly shortenproduction process and simplied the process, and reduction the energy consumption andproduction cost, and easily to realize the industrialization. |
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