.cu / Ni And Cu / Ni-p Multilayer Preparation And Electrodeposition Process Dynamics Analysis

Cu/Ni and Cu/Ni-P multilayers were prepared by electrodoposition method in this dissertation.We have observed the cross section and the surface morphology in virtue of scanning electron microscope(SEM). The electrodeposited behaviours in the initial stage and deposited process were investigated by cyclic voltammetry(CV),chronoamperometry(CA), electrochemical impedance spectroscopy(EIS).Main content of this paper is discussion about the effect of Cu²⁺,Cl^- and SDS on nickel and copper electrocrystallization by electrochemical method as well as the effect of Cu²⁺ and citrate sodium on metal crystallization kinetics behaviours in Watts+H₃PO₃ solution,and making an intensive analysis of electrodeposition mechanism.Main conclusion as follows:1,Cu/Ni and Cu/Ni-P multilayers were prepared by single bath technique(SBT) or double bath technique(DBT).Wavelength can be modulated through controlling electrodeposition time.The SEM of multilayers shows that copper and nikel layers are composed of fine pyramidal crystal;Ni-P plating's nodular structures make up of tiny particulates.The cross section of multilayers is distinct,and the thick is uniform and continuous.But the uniformity reduces along with monolayer thickness increase.2,Electrochemical tests show that the entering of Cu²⁺ accelerates nickel electrorystallization nucleation in Watts solution,and causes the initial depositon potential of nickel moving positively.In the case of lower overpotential,nickel electrocrystallization follows progressive nucleation curves in Watts+CuSO₄ solution.While in the case of higher deposition overpotential,it followers three dimensions instantaneous nucleation/growth mechanism controlled by diffusion.And Cu²⁺ decreases the transfer resistance of nickel under higher overpotential.3,Cl^- can affect the transfer resistance,increases both the nuclei number density and Cu²⁺ diffusion confficient.It has a promoting effect on the deposition process of copper in NiSO₄+H₃BO₃+CuSO₄ solution. Cl^- don't change the deposition mechanism of copper,the crystallization still follows three dimensions instantaneous nucleation/growth mechanism.SDS inhibits copper depositon,and making the depositon potential peak value negatively.While in the presence of Cl^- and SDS, SDS still inhibits it action and Cl^- promotes it.4,Na₃C₆H₅O₇ inhibits Ni-P deposition in Watts+H₃PO₃+ Na₃C₆H₅O₇ solution,the deposition rapidity becomes slow.Under higher over -potential,H₃PO₃ has an action of a catalyst on nickel crystallization nucleation/growth,leadⅠ-t curves appear multi current peaks.5,Bringing Cu²⁺ in Watts+H₃PO₃+Na₃C₆H₅O₇ system reduces the transfer resistance of Ni-P action,promotes Ni-P nucleation,and initial deposition potential moves positively.The electrocrystallization of Watts+H₃PO₃+Na₃C₆H₅O₇ system follows three dimensions nucleation/ growth mechanism,the entering Cu²⁺ don't change electrocrystallization mechanism of Ni-P.