Enhanced corrosion resistance of micro-arc oxidation coated magnesium alloy by superhydrophobic Mg−Al layered double hydroxide coating

Effects of Al3+ concentration in hydrothermal solution on the microstructural and corrosion resistance properties of fabricated MgO ceramic layer on AZ31 magnesium alloy

“…To maintain the charge balance, NO 3 − and CO 3 2− anions in the solution were intercalated and situated between the positive layers. [ 36 ] So, the Mg‐Al‐Zn LDH nanosheets formed in the micro‐pores and on the surface of the MgO ceramic layer. In the case where Al 3+ ions were not introduced into the reaction solution, only a small amount of LDH could be formed, depending on the limited amount of Al 3+ ions released by the dissolution of the MgO ceramic layer.…”

“…The presence of Na and Cl could be attributed to the NaCl solution adsorbed on the surface of the ceramic layer during immersion. [ 36 ] When the MgO ceramic layer‐coated sample was immersed in the NaCl solution, corrosive Cl − ions infiltrated the interface between the MAO ceramic layer and the substrate (along the micropores and cracks on the MAO coating). As a result, the Mg at the film‐substrate interface induced severe galvanic couple corrosion due to the low electrode potential.…”

“…Relatively few reports, however, exist on the preparation of LDH films on MAO ceramic layers of magnesium alloys. [32][33][34] In our previous work, [35][36][37] two composite LDH coatings (Mg-Al LDH/MAO and Mg-Al-Co LDH/ MAO) on magnesium alloys have been reported, which yielded an excellent corrosion resistance; however, the effects of Al 3+ concentration in hydrothermal solution on the microstructure and corrosion resistance properties of MgO ceramic layers on magnesium alloys have not been systematically studied. Our main focus in this study is to provide insight on this aspect.…”

A Review on LDH-Smart Functionalization of Anodic Films of Mg Alloys

“…Wang et al [ 93 ] prepared a superhydrophobic coating on the surface of PEO-coated AZ31 Mg alloy through the surface modification of LDH film by stearic acid (SA). Put simply, the Mg–Al LDH films were prepared by a hydrothermal process by immersion PEO-coated samples in a solution composed of Al(NO 3 ) 3 at 398 K for 6, 12, 18, and 24 h. The obtained samples were called PEO-LDH-6h, PEO-LDH-12h, PEO-LDH-18h, and PEO-LDH-24h, respectively.…”

Superhydrophobic Silane/Fluorinated Attapulgite@SiO2 Composite Coatings on Magnesium Alloy for Corrosion Protection

“…[4][5] A rough surface and low surface energy are the two key elements for designing superhydrophobic surface. Up to now, numerous methods of constructing superhydrophobic surface on magnesium alloys have been proposed, such as electrodeposition, [6][7][8][9][10][11][12] micro-arc oxidation, [13][14][15] chemical conversion treatment, [2,16] hydrothermal method, [17][18][19][20][21][22] immersion method, [23,24] laser ablation, [25] electroless plating, [26] dip coating, [27] spray coating, [28,29] et al Among these various methods, spray-coating technique is a fast, facile method to fabricate coatings on a large-scale, which has been widely used in industry for coating complex shapes on different substrates. [28,29] Organosiloxane is a promising candidate for the preparation of wear-resistant superhydrophobic materials due to its polymerization to enhance the mechanical durability and strong adhesion to the substrate.…”