Influence of Hard Anodizing on the Mechanical and Corrosion Properties of Different Aluminum Alloys

Abstract

Hard anodizing of different aluminum alloys 2014-T3, 6061-T6, and 7075-T6 is conducted in sulfuric acid electrolyte at a temperature of − 5 °C and current densities of 1.6 to 2.8 A/dm 2 for 30 to 60 min. The effect of substrate microstructure on the mechanical properties, corrosion resistance, and morphology of the hard anodic layers is investigated. Electrochemical technique, thickness, hardness, and abrasion testing devices are used to test the corrosion and mechanical properties of hard anodic layers. The morphology and nanostructure of the anodic film are observed by SEM. The results show that the 7075-T6 (Al-Zn-Mg-Cu) aluminum alloy has the highest hard coat thickness, hardness, and abrasion resistance. The Fe, Si intermetallic phases present in 6061 Al alloy hinder the oxide growth. The oxide layer formed on 2014 Al alloy has the lowest thickness, hardness, abrasion resistance, and corrosion resistance due to the high content of copper.

Effect of pulse current on surface properties of aluminum oxide coating containing graphite

“…In the present investigation, the authors fabricate an oxide layer with a thickness ranged from 50 μm, which is designed as protective coatings that can be applied to metals. A relatively thick oxide layer of 50 μm was formed at a constant current density of 15 A/dm 2 with fluctuating voltage at 15‐V maximum 36–39 . The frequency and duty cycle of the anodizing process were 0.025 Hz and 75%, respectively.…”

“…A relatively thick oxide layer of 50 μm was formed at a constant current density of 15 A/dm 2 with fluctuating voltage at 15-V maximum. [36][37][38][39] The frequency and duty cycle of the anodizing process were 0.025 Hz and 75%, respectively. The AA2017-T4 Al alloy substrate was used as the anode and 316 L stainless-steel plate with a dimension of 30 mm  60 mm was used as the cathode.…”

Effect of Anodic Oxidation on Tribological Behavior of 2017A Alloy

“…Coatings with oxides and phosphates are said to improve some properties of metallic surfaces such as hardness, wear resistance, electro-insulation properties [33]. The morphology, oxide growth rate, structure and composition of the anodic film affect the mechanical properties of the anodic film [34]. Since these parameters differ in different anodizing processes, the hardness of the coatings differ.…”

The microstructure and optical properties of novel Al2O3–Ag composite coating

“…This coating can be fabricated by the hard anodizing method to improve the corrosion resistance and mechanical properties of the aluminium alloys [5][6][7]. Hard anodizing can also be suitable to form a thick and abrasion-resistant oxide coating with a highly ordered structure [8,9]. The AAO (aluminium anodic oxide) coating with the columnar porous structure can be a host matrix for the embedment of the particles like Ag, Cu, TiO 2 , Al 2 O 3 , and Au to improve the wear, corrosion resistance, and optical properties [10][11][12][13][14][15].…”

“…Silver as a good emitter can be used in the form of nanoparticles whereas it can be co-deposited with Al 2 O 3 anodic film. Although there are a few works to evaluate the optical properties of the composite anodic films [8][9][10], no investigations have been done on the Al 2 O 3 -Ag composite coating. The main purpose of this research is to synthesize and characterize the microstructure and optical properties of novel Al 2 O 3 -Ag composite coating.…”