Low Temperature Reactivity of Aluminum Nanopowders with Liquid Water

International audienceIn this paper, we present an experimental study of the isothermal reaction of aluminum nanoparticles with liquid water in the temperature range [45 – 95°C]. Gas phase chromatography and X-ray diffraction analyses have revealed that the reaction Al + H 2 O yields to a solid aluminum oxyhydroxide (AlOOH) and to hydrogen (H 2). Hence, in order to describe the macrokinetics of the oxyhydroxidation of aluminum, the H 2 gas release was measured as a function of time and temperature. Furthermore, the effect of salt water (3% NaCl or KCl in mass) compared to pure water was investigated. It is shown that the hydrogen release is preceded by an induction period corresponding to the destruction of the oxide film initially covering the Al particles. The induction and the maximal hydrogen flow rate follow an Arrhenius law. Activation energies are calculated. In opposition to the works about the corrosion of salt water, the kinetics of reactions are slowed down by the addition of chloride ions