The 2A12 aluminum alloy is widely utilized in aerospace, automotive, and marine engineering due to its excellent strength-to-weight ratio and good machinability. However, its wear and corrosion resistance under harsh conditions are insufficient and require improvement. This study combined micro-arc oxidation (MAO) with paraffin sealing to enhance the corrosion resistance and tribological properties of 2A12 Aluminum Alloy. The results indicate that the MAO process significantly increases hardness and tribological properties, but the porosity into the oxidation layer may accelerate corrosion in corrosion environments. Paraffin sealing effectively fills these pores, reducing the penetration of corrosive agents and significantly improving corrosion resistance. Additionally, friction tests show that the hybrid coating after paraffin sealing exhibit a lower friction coefficient and wear rates. Molecular dynamics simulations (MD) further reveal the distribution of paraffin within the pores and its effect on wear and corrosion resistance. This study demonstrates that MAO combined with paraffin sealing is an effective approach to enhancing the corrosion and tribological properties of 2A12 aluminum alloy, providing new insights for its applications.
Poor mechanical properties is a key bottleneck limiting the application of graphite (Gr)/Al composites in thermal management structural components. A type of Gr (Graphene Nanoplatelets (GNPs))/2A12Al composites with excellent interface bonding and mechanical properties was developed. In this work, GNPs with height of about 204 nm were grown on the Gr flakes with chemical vapor deposition (CVD) and the Gr (GNPs)/2A12Al bulk composites were consolidated by powder metallurgy technique. The thermal conductivity , flexural strength and tensile strength of the composite were investigated. The results show that interface of the composite is well bonded, meanwhile the hardness and modulus of interface region are enhanced. Thermal conductivity of the composite is improved. Most importantly, the flexural strength and tensile strength are significantly enhanced. The maximum flexural strength reaches 344 MPa and tensile strength reaches 254 MPa when the volume fraction of reinforcement is 15 vol %. The remarkable strengthening effect is mainly attributed to the increase of mechanical locking effect at the interface and load transfer capability. Not only that, there is only a little decrease in flexural and tensile strength even after 200 thermal cycles for Gr (GNPs)/2A12Al composites.
Corrosion of aluminum alloys (Al alloys) has been a ubiquitous problem, and this seriously restricts its range of applications. Herein, a layer-by-layer (LBL) self-assembly method based on the formation and deposition of polyelectrolyte multilayers was employed to fabricate anticorrosion layers on 2A12 Al alloys for corrosion protection. LBL self-assembled films, with and without graphene oxide, were formed on Al alloy surface. The surface morphologies, roughness and chemical compositions of the as-fabricated LBL self-assembled films were characterized by several methods, such as, SEM, AFM, and XPS techniques. The electrochemical properties of the specimens were determined by EIS measurements. The comprehensive equivalent circuits were established to analyze the anticorrosion performance and inhibition efficiency of the resultant LBL self-assembled surfaces. The results indicate that the LBL self-assembled film exhibits inhibition efficiency over 99% in a 3.5% NaCl solution. After dragging to a distance of 200 mm or 400 mm, the inhibition efficiency of the LBL self-assembled film containing graphene oxide can still exceed 96%. LBL self-assembled films are considered to provide a new strategy for marine corrosion protection.
You Zhang,Juping Wang,Shuai Zhao,Maria Serdechnova,Carsten Blawert,Hao Wang,Mikhail L. Zheludkevich,Fei Chen
A promising double-ligand strategy for the delivery of active corrosion inhibitors by a Zn(II)-based metal–organic framework (Zn-MOF) is developed. Zn-MOF compounds were synthesized by a facile one-pot solvothermal method and characterized. The Zn-MOF is based on the corrosion inhibitor benzotriazole (BTA) and 2,5-furandicarboxylic acid (H2FDA) ligand, which is a promising renewable building block alternative to terephthalic or isophthalic acid. The crystal structure and morphology are characterized by single-crystal X-ray diffraction analysis, powder X-ray diffraction analysis (PXRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The synthesized MOF crystallites are in the trigonal space group R3c with the cell parameters in a three-dimensional (3D) anionic framework. Their ability to inhibit the corrosion process of aluminum alloy 2A12 in NaCl solution was also evaluated by immersion tests in solutions with and without a MOF. The postcorrosion analysis was performed by SEM and X-ray photoelectron spectroscopy (XPS). Additional information about the inhibition efficiency was obtained by electrochemical impedance spectroscopy (EIS). The results suggest that the as-synthesized MOF can release the inhibitors and form protective layers effectively on the surface of the aluminum alloy. The use of inhibitor-loaded MOF nanocontainers provides promising opportunities for the smart delivery of inhibitors and effective corrosion protection of 2A12 aluminum alloys.
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