Preparation of Non-Stoichiometric Tungsten Dioxide

摘要

Non-stoichiometric WO2 was prepared by the solid-solid reaction of W and WO3. Four different compositions, WO1.94, WO1.97, WO2.00, and WO2.02 within the range of homogeneity of WO2 were prepared in this way. The presence of other phases consisting of W, WO2.72, and WO2.90, WO3 was detected by x-ray techniques with the limits of detection being W, 0.1 -0.2%; WO2.72, 3%; WO2.90, 2%; WO3, 0.4-0.5%. The limits of homogeneity of WO2 were found to be WO1.940 and WO2.025. Sampmamples of WO2 having the four above-mentioned compositions were also prepared to contain 2.4% O18. Samples containing W185 were prepared by thermal neutron irradiation of WO2. (Author)