Deposition Of Al And Al Alloy From Ionic Liquid And Their Corrosion Behavior

Coating of aluminum alloy(especially Al-Mn alloy) has the advantage of good anti-corrosion, high hardness, good looking and brightness, which is regarded as a kind of promising coating in the near future. Nowadays Ionic liquid is concerned by people for low melting point, high conductivity, almost no pressure, wide electrochemistry window, good thermal stability and environmentally friendly. As a result, deposition of aluminum alloy from ionic has become a central issue. This paper is mainly about,deposition of Al and Al-Mn alloy on low carbon steel from AlCl3-EMIC(l-ethyl-3-methylimidazolium chloride) and AlCl3-MnCl2-EMIC,the corrosion behavior of Al and Al-Mn alloy coating are also remained; Using ionic liquid(AlCl3-ZnCl2-EMIC) to deposit Al-Zn alloy on low carbon steel.It turns out, we successfully get a dense Al and Al-Mn alloy of good attachment on20#steel at the current density of6mA/cm2.The deposition time is4hours. When the content of MnCl2is0.03mol/L, the Al-Mn coating appears the mixture of crystalline and amorphous. EDS shows the content of Mn is7.1at%, so this kind of coating is recognized as Al-Mn-L in this paper. When the content of MnCl2is0.10mol/L, the Al-Mn coating appears amorphous entirely. The content of Mn is20.26at%.We recognize it as Al-Mn-H. According to Tafel curve, the corrosion current density of Al and Al-Mn is lower than that of20#steel, and the corrosion current density of Al-Mn is lower than that of Al. The corrosion current density of Al-Mn-H is lower than that of Al-Mn-L.A preliminary study on deposition of Al-Zn coating on20#steel is carried out in AlCl3-ZnCl2-EMIC room temperature ionic liquid. According to the Cyclic Voltammetry, when the potential is below0.24V, Zn deposits.Drop to-0.1V,Al also deposits.At the condition of-0.3V,1h, we can get uniform Al-Zn coating. The size of grain is1-2μm, but it looks grey, lack of metallic luster. In order to get shining Al-Zn coating, we add some vanillin、EDTA、nicotinic acid and citric acid, the coating is still grey, but the grain becomes smaller.