Investigation of MoOx/Al2O3 micro-arc oxidation coatings on corrosion performance based on AlSi10Mg selective laser-melted

The MoOx/Al2O3 micro-arc oxidation composite coatings based on the AlSi10Mg selective laser-melted were studied to lay a foundation for its application in aerospace. The MO32- ion group diffused into the coatings and participated in the reaction, forming MoOx compounds. The Mo content increased to 3.45 %, uniformly distributed across the surface and in-depth. The coatings mainly comprise gamma-Al2O3, alpha-Al2O3, MoO2, and MoOx. The valence of Mo was Mo4+, Mo6+, and Mox+ in MoO2, MoO3, and MoOx, respectively. The average surface roughness increased from 0.729 gm to 2.784 gm. The corrosion current decreased from 1.122x10-5 Axcm2 to 2.774x10-7 Axcm2. The micro-hardness of the coatings was improved from 536 HV to 925 HV. The corrosion products consist of Al (OH)3 and AlCl3. The Cl- content of the 4-week sample is close to that of the 1-week sample; the Cl- content does not increase with the prolonged corrosion time, and MoOx/Al2O3 composite coatings excellently protect the substrate.