On the reduction of N.S.-doped tungsten blue oxide—Part III: Technological considerations

Abstract

Part I of this paper gave a review of the literature, Part II presented a mechanism for the doping element incorporation during reduction and Part III now discusses technological relationships between the reduction parameters and the N.S.-W powder properties. Under isothermal reduction conditions, dopant incorporation is affected predominantly by the reduction temperature (decreasing with increasing temperature), while grain size is influenced by both temperature and boatload. During temperature profile reduction (industrial practice) all parameters influencing the relationship between actual reduction temperature and reduction stage (WO X) affect both grain size and dopant incorporation. Besides the absolute amount of incorporated dopants, the sizes and compositions of the incorporated dopant phases are affected as well, an important factor with respect to the further processing to high-quality non-sag wire.