Reactivity of Nanosize Aluminum with Metal Oxides and Water Vapor

Abstract

ABSTRACTIt has been well documented that the reactivity of nano-powders as well as bulk properties of materials derived from nano-particulates might be significantly different than those obtained from micron-sized grains. This paper addresses several aspects related to the characterization of coated and uncoated aluminum nanopowders, mixing of binary nanopowders, and the reactivity of nanosize aluminum with copper oxide under unconfined and confined conditions. It was found that the volumetric method is more versatile method than TGA or calorimetry for determination of reactive aluminum in coated aluminum nanopowders. It was shown that wet mixing in the presence of dispersants is essential to obtain mixtures with a high level of concentration uniformity. The combustion front velocity can be increased both by using an excess of aluminum in MIC systemand by coating of aluminum nanopowders or addition of dispersants during wet mixing. Protective organic coating with hydrophobic groups is essential to protect aluminum nanopowder from the reaction with moisture at higher relative humidity levels.