Aluminum nanoparticles oxidation by TGA/DSC: Parametric analysis and oxide thickness determination

Aluminum nanopowder oxidation is mostly experimentally studied through thermogravimetric analysis (TGA) combined with differential scanning calorimetry (DSC). These types of analyses are very sensible to a variety of parameters such as the heating rate, oxidizing gas composition or sample mass. Also, theoretical models of aluminum nanopowder oxidation are based on the evolution of the oxide thickness, whereas the outcome of TGA experiments provides a mass evolution. Moreover, the determination of the oxide thickness from a tested sample of aluminum nanopowder is not straightforward. Models are available in the literature but are not always validated and have never been compared with each other. This article first summarizes a literature survey on the influence of different parameters on TGA/DSC experiments and secondly discusses the analyses of TGA/DSC experiments with aluminum nanopowders produced by inductively coupled plasma. Guidelines on the best parameters to use for TGA/DSC experiments are provided. In parallel, three models, found in the literature, used to calculate the oxide thickness from a given mass increase by TGA/DSC experiments, but with different input variables and assumptions, are summarized and compared theoretically. The models are then applied to estimate the thickness of the oxide layer of aluminum nanoparticles produced by inductively coupled plasma. The calculated thicknesses are then compared with each other and validated against the oxide thickness determined using TEM images.