RESUMEN
Coatings with only passive protection cannot offer long-term anticorrosion on metals. Eco-friendly sustainable and responsive coating for active/passive corrosion protection is desirable to extend the service life of metals. Here, benzotriazole (BTA)-metal organic frameworks (Cu-MOFs, UiO-66) were embedded in silica (SiO2) coating by one-step electrodeposition on copper. Combined with passive capability of MOFs and active protection of BTA inhibitor, the composite coating (BTA-MOF/SiO2) exhibited high and stable corrosion resistance, confirmed by microstructure characterizations and electrochemical tests. As a result, the as-prepared composite coating exhibited superhydrophobicity with a water contact angle of 154.2°. With loading of BTA-MOF in SiO2 coating, the impedance modulus at 0.01 Hz increased by â¼10-fold and the corrosion current density decreased to 3.472 × 10-9 A·cm-2. Immersion and salt spray tests confirmed the long-term protection of the composite coating. The responsive release of BTA inhibitor endows the coating with a responsively anticorrosive behavior. The active-passive ability makes the coating a good candidate for protection on metals used in highly salty environments.
RESUMEN
Aluminum alloy (Al alloy) suffers from severe corrosion in acidic solution. Two-dimensional (2D) MXene-based composite coatings show great prospects for corrosion protection on metals used in special conditions. The composite coatings still face challenges in complex functionalization and orientation control. In harsh conditions, the long-term ability and roles of MXene in corrosion protection are still not clear. Here, a bio-inspired myristic-calcium chloride-Ti3C2Tx MXene (MA + CaCl2 + MXene) composite coating is successfully prepared on aluminum alloy (Al alloy) by electrodeposition process. Electrochemical tests, surface morphology, and chemical composition are analyzed to investigate the corrosion resistance and protection mechanism of the MXene coating in acidic solution (0.5 M H2SO4 + 2 ppm HF). As a result, the incorporation of MXene can significantly reduce corrosion current density (7.498 × 10-8 A/cm2) by â¼ 5 orders of magnitude and impedance modulus at 0.01 Hz (|Z|0.01 Hz) value of the composite coating is 196.8 Ω·cm2, which is over 4 times higher than that of bare Al alloy (40.74 Ω·cm2) after immersion test for 72 h. Furthermore, the in-situ corrosion test confirms the enhanced corrosion resistance of the MA + CaCl2 + MXene composite coating. The MXene can increase coating thickness to 23.6 ± 0.4 µm, reduce porosity to (5.845 ± 1) × 10-5, decrease the diffusion coefficients of H+ to (1.587 ± 0.3) × 10-9 cm2/s, and enhance the adhesion of the coating to the substrate (the delamination time exceeds 5 h), thus providing improved anti-corrosion ability. This strategy opens up new prospects for construction of 2D MXene-based anti-corrosion coatings.
RESUMEN
Separation meshes with special wettability for oil/water separation have drawn much research attention and the preparation of superhydrophobic or underwater superoleophobic materials for oil/water separation has been extensively studied. However, the preparation procedures of inorganic coatings in previous studies were complex and the widely used organic compounds for surface modification were costly and unstable. To address these challenges, the layer-by-layer self-assembly process of inorganic sodium silicate and aluminum oxide powders (SSA) on the copper (Cu) mesh was explored in this paper. Hierarchical and rough structures after electrodepostion were observed by scanning electron microscope (SEM). On the SSA modified Cu mesh, contact angles (CA) of underwater trichloromethane and water in the air were 153° and 1°, respectively. Besides, the modified mesh exhibited high thermal stability, good oil/water separation properties with water flux of 19832 Lm-2h-1 and separation efficiency > 95%, and high recycling performance. The oil/water separation mechanism was that the positive intrusion pressure and the repulsive force for oil contributed to the oil/water separation performance of the mesh. The obtained mesh featured in facile design, unique wettability (underwater superoleophobic), high flux, and good recyclability and thermal stability. Therefore, it is believed that the self-assembly strategy proposed in this paper may provide a reference for preparing a highly stable inorganic mesh for oil/water separation.