Oxidation of pure aluminium granules during in-situ melting

摘要

Oxidation behaviour of in-situ melted pure aluminium was investigated. The granules were heated in ceramic investment casting moulds between 700 and 850oC, for the duration of 30 and 60 min in atmospheric air using high temperature muffle furnace. The product was visually inspected macroscopically for the geometry and appearance. Scanning electron microscope (SEM) together with energy dispersive x-ray spectroscopy (EDS) was employed to analyse the oxidation characteristics of the product. Macroscopically, the granules failed to melt and unable to produce a casting even when the temperature was increased to 850oC. The surface of the granule experienced oxidation and spalling. Both temperature and heating duration were found to influence geometry and appearance of the product and also oxidation behaviour. The oxide layer encapsulated the granule during investment casting of Al granules by in-situ melting technique was Al2O3