Titanium Aluminum Alloy Electrodeposition In Ionic Liquids

With the development of Aerospace undertaking in our country, the titanium and Ti-Al alloys are now in widespread used. However, there are many drawbacks, for example energy consumption and environmental pollution and so on, exist in the current industry methods of titanium and Ti-Al alloys, it is an urgent task to find out the new green production methods that consistent with low energy consumption and emissions.This paper describe the new progress of electrodeposition of titanium and Ti-Al alloys in ionic liquids at home and abroad, analysise the potential applications of electrodeposition of titanium and titanium alloys in the ionic liquids,1) Some ionic liquids were synthesized, The results of IR indicate the target products;2) The conductivity of ionic liquids and adding TiCl4 were measured, the conductivity is even greater after adding TiCl4, and its lnκand 1/T consistent with the Arrhenius equationκ=Ae-Ea/RT, lower activation energy Ea is calculated, it is benefit for metal electrodeposition;3) From the Cyclic voltammetry curves, we can obtained two pairs of redox peaks in [bmim]BF4+TiCl4 and [bmim]PF6+TiCl4 systems, the metal may be electrodeposited titanium, But can not be electrodeposited at the ionic liquid system of choline chloride +urea;4) By the Cyclic voltammetry curve of acidic [bmim]Cl-AlCl3+TiCl4, we founed three pairs of redox peaks, we can suggest that co-deposition of titanium aluminum can be achieved in it, in addition, also v1/2 become a linear relationship between ipc, the cathodic electrode process is mainly controlled by diffusion and quasi-reversible process;5) Through the anode valence of the dissolution and the corresponding Cyclic voltammetry curve, we suggest that titanium is oxided to the low-cost titanium at the first step, and then oxided to tetravalent titanium;6) The results of electrodeposition experiment of titanium in ionic liquids showed as fellows:Layer of brown that called TiCl3 attached to the electrodes surface, titanium can not be electrodeposited from these ionic liquids. As the complexity of the valence of titanium ions in process of electrodeposition and the low-cost titanium chloride have the low solubility in ionic liquids, new sources of titanium and appropriate ionic liquids need to be finded.7) In this article, the acidic [bmim]Cl-AlCl3+TiCl4 used as the electrolyte which electrodeposition of Ti-Al alloys, the effect of process variables such as substrate materials, temperature and so forth on current efficiency, composition and morphology of Ti-Al alloys, set the single-factor electrolysis conditions, and the layers were analyzed by SEM, XRD and EDS and other test methods. Finally, we obtained as follows,The concentration titanium ions in the electrolyte had no significant effect on Ti content of Ti-Al alloys, current efficiency and so on. at low applied voltage, temperature, current density (1.5V,50℃,1.0mA·cm-2), leads to uniform paticle size, independent, but leads to lower productivity, In contrast, at high applied voltage, temperature, current density (1.8～2.0V,70～80℃,5.0mA·cm-2), obtain larger particle size, the most smooth, good adhesion, the best surface morphology of electrodeposited layer;it is easy to form large grains, serious dendrites and poor adhesion when they too high (2.5V,90℃).