Preparation And Anticorrosion Properties Of Tantalum And Zirconium Films By Electrodeposition In Imidazole Ionic Liquids

At present,Ta and Zr are two kinds of film metals with strong application potential and research value.Their strong corrosion resistance and environmental friendliness are favored by the nuclear industry.At the same time,ionic liquid system is an emerging research hotspot which has more advantages over traditional film preparation schemes.In order to investigate the preparation process of electrodeposited films of two metals in ionic liquids,the electrochemical reduction process of TaCl₅ in two imidazoluminate ionic liquids has been investigated,and the dissolution phenomenon and deposition results have been analyzed.Then,the preparation method of codeposited alloy films of Ta,Zr and Alin imidazoluminate ionic liquids has been studied.Finally,the effects of some specific electrodeposition parameters（zirconium source concentration,current parameters,temperature,additives）on the properties of the obtained codeposited Al-Zr alloy films were studied in detail.The cyclic voltammetry curves of TaCl₅ in ionic liquid BMIMBF₄ and BMIMCl show that the reduction of Ta（V）in ionic liquid goes through the process from Ta（V）to Ta（III）,and then to Ta and low cost Ta chloride.The process of Ta（V）to Ta（III）is relatively easy.The diffusion coefficient of 0.1 mol/L TaCl₅ in the BMIMCl system is calculated to be 7.36×10^-10 cm²s^-1.Due to the properties that tantalum is easy to form clusters and complex structures,Ta film cannot be obtained by electrodeposition on metal substrate.The co-deposition process of Ta（V）and Zr（IV）with Alin imidazolo-aluminate ionic liquid with molar ratio of 2:1 was investigated.The results show that it is difficult to form a complete and uniform alloy film on Al-Ta in this system,but Al-Zr alloy layer can be prepared on copper substrate and steel substrate.The surface of the film is smooth and bright,which has a high degree of coverage on the substrate.Finally,by adjusting the electrodeposition parameters of Al-Zr alloy on 35#steel substrate and combining with the results of multiple characterization of the prepared films,the effects of the preparation technology on the properties of the films were studied.The results show that under the set process parameters,when the zirconium source content is 35 mmol/L,the constant current deposition,the current density is 10 m A/cm²,the temperature is 318.15 K and the concentration of Li F additive is 35 mmol/L,the aluminum zirconium alloy film with the best corrosion resistance and the best surface properties can be obtained.