Features of passivation, oxidation and combustion of tungsten nanopowders by air

The passivation, oxidation and combustion of tungsten nanopowders (NP) (a(s) similar to 100 nm), produced by an electrical explosion of wires (WEE) method, has been studied in air medium. The phase transformation for W nanopowders under air-oxidation was investigated. The oxidation process and an analysis of passivated powders were studied by FESEM, EDS, XPS, XRD, TEM, DTA-TGA and size distribution analysis was also observed by a video camera. After the comprehensive testing of passivated, oxidized and burned powders, a chemical process of oxidation of W nanoparticles was suggested. (C) 2004 Elsevier Ltd. All rights reserved.