Removal of iron from BaTa2O6 ceramic powder produced by high energy milling

Abstract

In order to remove Fe coming from the milling environment, mechanochemically produced BaTa2O6 ceramic powder was leached with 6 and 12 M HCl at 95 degrees C and 105 degrees C for time periods varying between 1 and 15 h. Amount of Fe in leached samples was determined by EDS and XRF. Fe concentration decreased from 10.36% to 1.97-3.16% after leaching indicating a 70-81% decrease in iron. Leaching temperature had a more pronounced effect on iron removal than concentration. Leaching caused the formation of porosities and disintegration of powder which accelerated the iron removal. X-ray diffraction analysis of leached milled powders heat treated between 1000 and 1450 degrees C for 5 h indicated that although iron related phases were formed above 1000 degrees C, single BaTa2O6 phase was obtained at 1425 degrees C having tetragonal tungsten bronze type structure. A possible liquid phase formation above 1300 degrees C led to an increase in grain size and density. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.