Hard Anodizing and Plasma Electrolytic Oxidation of an Additively Manufactured Al-Si alloy

Plasma Electrolytic Oxidation (PEO) and Hard Anodizing (HA) coatings are investigated on an Additively Manufactured (AM) Al10Si1Mg alloy obtained via Direct Metal Laser Sintering (DMLS). Results are compared to those obtained for a conventional A361 cast alloy. Findings revealed that the microstructure of the AM alloy, consisting of α-Al cells enclosed in a Si network, produces coatings that are more uniform –in terms of morphology, thickness and roughness of the coating/substrate interface– than those obtained on the cast alloy. However, enhanced oxidation of the fine Si network in the AM alloy results in softer coatings. In both alloys, PEO coatings demonstrate superior wear protection than HA due to the presence of mullite in the former. The anisotropy in the microstructure of the AM alloy influences the tribological behaviour of studied coatings, with the XZ plane showing superior wear performance. •Anodic films by HA and PEO are studied on DMLS Al10Si1Mg and cast A361 alloys.•Anisotropy in the AM alloy is translated into HA and PEO coatings.•Wear resistance of PEO is superior to that of HA for both alloys.•Oxidation of the fine 3D Si network in the AM alloy results in softer coatings.