Electrodeposition Of Fe&Sn In Ionic Liquid

Ionic liquid （IL） is also known as room temperature molten salt, which is a liquidconsists of cations and anions at room temperature. As a new developed solvent, ILowns several properties i.e. wide electrochemical window, excellent solubility for bothorganic and inorganic materials, low vapor pressure and little poison.The choline chloride/ethylene glycol solution used in this study is one kind of IL.This solution is widely used in the industry of eletrodeposition because of its low cost,convenient preparation, high conductivity, wide electrochemical window and it’s stableto air and moisture. This study is focused on the electrodeposition of Fe and Sn in thisIL.The eletrodeposition of Fe is used in the field of wear components repair andelectroforming of mechanical parts. It’s also used to improve the lifespan andmechanical propertied of printed circuit board. This technology is low-cost and widelyused in the manufacturing industry.The electrodeposition of Sn is also an important technology. Since Sn film is easyto welding so it’s used in the production of electronic components and semiconductorindustry. The deposition coating of Sn is not easy to tarnish or to be sulfide. SometimesSn can take the place of Ag for certain special use.In the IL electrolyte mentioned above, direct current electrodeposition and pulse（monopulse） electrodeposition of Fe and Sn were studied in this research. Comparedwith direct current eletrodeposition, pulse electrodeposition can achieve depositioncoatings with better properties, i.e. abrasion and corrosion resistance, high intensity,purity and conductivity. Pulse electrodeposition is also used to deal with precious metal.This technology has more parameters than direct current electrodeposition to control, soit’s easy to change the properties of the final deposition coatings.Through the analysis of scanning electron microscope （SEM）, energy dispersivespectrometer （EDS） and X-ray diffraction （XRD）, it found that the reaction temperature,deposition additive, reaction time and pulse duty factor had effect on the configurationand composition of deposition coatings. During the direct current electrodeposition of Fe, the deposition coating was madeof small round balls, the ratio of Fe increased as the temperature became higher. Afterwashing the deposition coating in the NaBH₄solution, its properties became worse. Asthe reaction time increased, it turned to habe more cracks and worse adhesion.As the monopulse electrodeposition of Fe, higher pulse duty factor tended toachieve better depositon coatings. There are many folds on the surface of the depositioncoating. At the same time, longer reaction time leaded to more cracks. The comparisonof the linear sweep voltammetry curve of the electrolyte both before and after reactionshowed, after reaction the voltage needed to make the biggest electroactive substanceconcentration turned bigger. The cyclic voltammetry curves stayed almost same.During the direct current electrodeposition of Sn, at the same temperature, thegrains on the surface of the deposition coating tended to be uneven distributed after ashorter reaction time, while the adhesion of the coating decreased as the reaction timebecame longer.During the monopulse electrodeposition of Sn, higher reaction temperature andlonger reaction time tended to achieve intensely arranged, even distributed depositioncoatings. While few aluminum impurity made special structure as the pineapple leaveson the surface of the deposition coating. The linear sweep voltammetry curve showed,after reaction the voltage needed to make the biggest electroactive substanceconcentration turned bigger. The cyclic voltammetry curves also stayed the same.