The morphology and the structure of the Al-Mn alloys electrodeposited from the molten A1Cl3-NaCl-KCl-MnCl2 salts were investigated using scanning electron microscope, X-ray diffraction.
The alloys became lustrous with an increase in Mn content. X-ray diffraction patterns of these alloys showed that the alloys of lower Mn content consisted of α-Al crystalline phase. With an increase in Mn content, the intensities of the diffraction peaks from the crystalline phase decreased, while a broad peak appeared.
Further, the microstructures of electrodeposited Al-Mn alloys of various Mn content were observed by transmission electron microscope. The electron diffraction pattern of ca. 7 mass % Mn alloy showed α-Al polycrystalline phase. With an increasing Mn content in deposit, the alloy phases changed from a-Al to amorphous phases. These phases showed lamellar structure which was parallel to the substrate.
In electron diffraction images of Al-Mn alloy of ca. 30 mass % Mn, four broad rings were observed and they werereflected from microcrystalline intermetallic compound Al6Mn with the grain size of 3 to 5nm.
