The influence of different oxidation processes on micron-sized aluminum particles

摘要

The objective of this work is to investigate experimentally the oxidation behavior of micron-sized aluminum particles with controlled thickness of alumina passive layers in oxidized environment. Samples in four different sizes were studied using differential scanning calorimetry, thermogravimetry analysis and mass spectrometry (DSC-TGA-MS). Oxidation process of aluminum particles can be divided into four stages and partially oxidized samples of specific stages were collected then analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). Oxidation rates of micron-sized aluminum particles are affected by the gas byproducts during the main reaction period. The thickness of alumina layer outside aluminum particles were thickened by controlling the heating process and the results of identical heating process demonstrated that alumina passive layer has a clear restriction on the oxidation process. The thicker of the alumina shell is, the harder the mass diffusion is going through. In this gradually heating system, oxidation of aluminum particles at low temperatures range is dominated by diffusion of ions on both sides of alumina shell, whereas the reaction at higher temperature is controlled by kinetics. When the alumina shell was manually treated to a thicker degree, the oxidation process of micron-sized aluminum particles can be totally suspended.