Rapid synthesis of submicron crystalline barium zirconate BaZrO_3 by precipitation in aqueous basic solution below 100 deg C

摘要

Pure crystalline BaZrO_3 powders can be produced by precipitation in highly basic aqueous solution. The influence of several synthesis parameters is studied. At high OH~- concentration ([NaOH] = 20 mol/1), it is possible to obtain the well-crystallized stoichiometric perovskite phase at relatively low temperature (approx 80 deg C), after a short reaction time (15 min) and without requiring any precaution to avoid the presence of CO_2. This synthesis method yields spherical particles, whose size can be controlled by changing the concentration of the Ba+Zr solution. No calcination treatment is necessary since the precipitate is crystalline. Suitable choice of the synthesis parameters ([NaOH] = 20 mol/1, [Ba + Zr] = 1 mol/1, reaction time= 15 min) yields a sub-micron precipitate with excellent densification behaviour. Corrosion tests in BaO-CuO melt show that approx 98 percent dense BaZrO_3 obtained by sintering at 1650 degC for 13 h could be used for crucibles in the synthesis of YBa_2Cu_3O_7superconducting single crystals.