1：Experimental Design and Method Selection:

The study involved preparing micro-arc oxidation (MAO) coatings with and without graphene on a laser-MIG hybrid welded joint of 6061 and 7075 aluminum alloys. The MAO process was conducted in an alkaline-silicon electrolyte, and graphene was added to the electrolyte for composite coatings. The corrosion behavior was evaluated through electrochemical tests and immersion corrosion tests.

2：Sample Selection and Data Sources:

Samples were machined from the welded joint, divided into five zones: base metal of 6061Al (6-BM), heat-affected zone of 6061Al (6-HAZ), weld zone (WZ), heat-affected zone of 7075Al (7-HAZ), and base metal of 7075Al (7-BM). Data were obtained from SEM, EDS, XRD, and electrochemical measurements.

3：List of Experimental Equipment and Materials:

Equipment included SEM (EVO-18 ZEISS and VEGA3 TESCAN), EDS (INCA Oxford), XRD (X' Pert3 Powder), electrochemical workstation (CHI660E), and a circulating cooling system. Materials included 6061 and 7075 aluminum plates, ER5356 filler material, NaOH, EDTA-2Na, Na2SiO3, and graphene.

4：Experimental Procedures and Operational Workflow:

The welded joint was cleaned ultrasonically in acetone. MAO was performed in the electrolyte at a working frequency of 500 Hz, with temperature maintained at 30°C. Coatings were prepared with and without graphene. Surface and cross-section morphologies were observed, and elemental analysis was conducted. Electrochemical tests were performed in a 3.5% NaCl solution using a three-electrode cell.

5：5% NaCl solution using a three-electrode cell. Data Analysis Methods:

5. Data Analysis Methods: Data were analyzed using electrochemical software for polarization curves. SEM, EDS, and XRD were used for microstructural and compositional analysis.