Oxide Layers on Rapidly Solidified and Bulk Al-Si-Zr Alloys Formed by Oxidation in Air and Anodizing Process

Abstract

Al-Si-Zr alloys have been studied as bulk samples and as rapidly solidified ribbon. Non-homogeneous structure in cross section of the ribbon has been observed. Authors are reporting significantly different nano- and microstructure of the “wheel” and “air” side of the ribbon samples. Some oxidation studies at 5000C in air have been performed. Results on both ribbons and bulk samples in as-cast state and after heat treatment are discussed. Ribbon surfaces are characterized mainly by atomic force microscopy (AFM) and oxide layers are studied in scanning electron microscope. High temperature oxidation experiments in air show appearance of non-uniform oxide layers on the free surface of specimens. By anodizing process a thick continuous oxide layer was found to form on Al-Si-Zr alloys. The thickness of the layer is varying around 80 μm according to SEM study. Results are discussed in terms of the above findings.