A New Nonspherical Oxidation Model of Metal Particles

This paper analyzes the oxidation law of metal particles and proposes a new oxidation reaction rate model, based on measurements of thermogravimetric-mass spectrometer (TG-MS), X-ray diffractometer (XRD) and scanning electron microscope (SEM). The model is named EBM (egg broken model) with a formula of exponential law. According to the model, the aluminum particles do not react in a spherical shape, but crack and the melted metal inside flows out to form a new nonspherical surface and the reaction rate is still determined by the surface area. The model is verified with heating rates of 5°C/min, 10°C/min and 25°C/min, and with particle size of 1–2 µm, 8–9 µm and 20–22 µm. Many models are based on spherical hypothesis and the new model gives a different physical illustration to explain oxidation progress of metal particles. The new model gives an exponential law, which fits the experimental data well, and it may be useful to understand oxidation mechanism of metal particles.