Aluminum plays an essential role as an excellent coating material in diversified applications due to its better corrosion resistance and physicochemical properties. Employing such a material as a coating on different metallic substrates such as carbon steel would benefit many industries such as the automotive, aviation, shipbuilding, construction, electronics etc. Amongst the various available coating techniques, electrodeposition of aluminum (Al) Al alloys have gained significant attention in the last 10 years as a metallic protection coating for various commercial substrates and has become the industry’s choice owing to being lightweight, corrosion-resistant, and cost-effective. This paper shall provide a detailed review covering electrochemical deposition of Al and Al alloys using ionic liquids with various cations, anions, and additives, and reports on progress in development thus far. It shall also cover the challenges in the electrodepositing aluminum, its alloys on light weight metal substrates viz., magnesium (Mg), commercial substrates such as low carbon steel, spring steel, and their pretreatments. The factors that play an important role in electroplating on an industrial scale, along with future challenges, are discussed.

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A Review on the Electrodeposition of Aluminum and Aluminum Alloys in Ionic Liquids

Electrodeposition of aluminium on the copper substrate using two different chloroaluminate ionic liquid electrolytes such as AlCl3/1-Butyl-3-methylimidazolium chloride electrolyte (AlCl3-BMIC) and ...

Structure, microstructure and electrodeposition behaviours of aluminium from AlCl3-EMIC and AlCl3-BMIC ionic liquid electrolytes – a comparative study

A new three-layered film was fabricated on magnesium (Mg) alloy via electroplating to guard against corrosion in a chloride aqueous environment, which consisted of an underlying double-layered zinc/copper (Zn/Cu) and a top aluminum-zirconium (Al-Zr) layer. The Zn/Cu underlayers not only impeded the galvanic corrosion between the Al-Zr coating and Mg alloy but also improved the adhesive ability between the substrate and the upper Al-Zr layer. Herein, we discussed the nucleus sizes of Al-Zr coatings at the stage of nucleation carried out with different contents of ZrCl4 in AlCl3-1-butyl-3-methylimidazolium chloride ionic liquid. The sandwichlike three-layered Zn/Cu/Al-Zr coatings were systematically investigated by surface morphology, phase structure, hardness, anticorrosion performances, and first-principles calculations. The corrosion current density declined from 1.461 × 10-3 A·cm-2 of bare Mg to 4.140 × 10-7 A·cm-2 of the Zn/Cu/Al-Zr3 sample. Neutral salt spray testing demonstrated that the Zn/Cu/Al-Zr3 sample showed no evident signs of corrosion after 6 days of exposure. The enhancement of the corrosion protection property was related to the fact that the application of the Cu layer changed the corrosion direction from initial longitudinal corrosion to extended lateral corrosion and the top Al-Zr coating hindered the transmission of aggressive ions. In addition, upon increasing the Zr content in the alloy films, the Fermi energy reduced initially and then increased. The Al-Zr3 alloy with 8.3 atom % Zr showed the lowest Fermi energy (-3.0823 eV), which exhibited the most efficient corrosion protection. These results showed that the prepared three-layered coating provided reliable corrosion protection to Mg alloy and may thus promote its practical applications.

Design and Fabrication of a Sandwichlike Zn/Cu/Al-Zr Coating for Superior Anticorrosive Protection Performance of ZM5 Mg Alloy

In this study, micro-arc oxidation (MAO) coatings were formed on ZM5 Mg alloy substrate with different surfaces roughness. Therefore, the influence of surface roughness on the corrosion failure progress and mechanism of the MAO coated ZM5 Mg alloy has been investigated. The microstructure, bonding strength, and corrosion resistance of the MAO coatings were studied by SEM, LSCM, bonding strength measurement, and electrochemical test. The results showed that the surface roughness affects the porosity and bonding strength of the coatings. While it had little effect on the thickness and chemical composition of the MAO coating. Due to the high surface porosity, the coating of the grooved sample had poor corrosion resistance in the initial immersion. But, after a long-time immersion, the grooved sample was still protected by the coating, while the smooth sample showed severe damage. The strong bonding strength between the coating and groove sample was the key factor for enhancing the corrosion resistance of MAO coated ZM5 Mg alloy. 

Influence of surface roughness of substrate on corrosion behavior of MAO coated ZM5 Mg alloy

Simulation of Aluminium Electrodeposition on Complex Geometry: Influence of Input Parameters and Electrodeposition Conditions

The influence of overpotential on electrodeposited aluminum coating onto zincated ZM5 magnesium alloy in ionic liquid

The invention provides a method for improving surface binding force of an aluminum plating layer and a magnesium alloy. The magnesium alloy is adopted as a cathode, a pure aluminum sheet is adopted asan anode, and an electrochemical workstation or a dual pulsed power supply is adopted for carrying out electroplating in ion liquid electroplating liquid; and the ion liquid electroplating liquid isobtained by the following method which comprises the steps that 1-butyl-3-methylimidazole chlorine salt ion liquid and anhydrous aluminum chloride are mixed according to the molar ratio being 1:1.5-1:3 and are stirred to be completely dissolved, and an additive is added according to the mass ratio being 0.5-1 g/L. According to the method, the binding force and corrosion resistance of the aluminumplating layer are improved, and the high-purity and compact aluminum plating layer can be obtained.

Method for improving surface binding force of aluminum plating layer and magnesium alloy

The invention discloses a method for electrically depositing an Al-Zn (aluminum-zinc) alloy plating layer at the surface of magnesium alloy, and belongs to the field of surface corrosion technique andprotection of magnesium alloy of active electrodes. The method comprises the following steps of sequentially grinding the magnesium alloy sheet, cleaning by ultrasonic waves, cleaning by acid, cleaning by alkaline, activating, soaking with zinc, washing by alcohol, washing by water, and drying by air; cleaning the Al sheet and the Zn sheet by ultrasonic waves, cleaning by alkaline, and drying; performing pulse electric deposition in a plating liquid, using the magnesium alloy as a cathode, and using the Al sheet or the Zn sheet as an anode, wherein the external pulse voltage of the pulse electric deposition is 0.5V to 1.5V, the frequency is 20 to 100Hz, the empty ratio is 20%, the time is 30 to 60min, and the temperature is room temperature; stirring the electric deposition process at therate of 120 to 200r/min.

He Yandong

Papers

The influence of overpotential on electrodeposited aluminum coating onto zincated ZM5 magnesium alloy in ionic liquid

Method for improving surface binding force of aluminum plating layer and magnesium alloy

Method for electrically depositing Al-Zn (aluminum-zinc) alloy plating layer at surface of magnesium alloy