Solid-solid reactions, I: Experimental study of barium metatitanate synthesis

International audienceThe solid-state reaction between barium carbonate and rutile powders to form barium metatitanate BaTiO3 was studied by thermogravimetric analysis, X rays, and microscopy. Phase-stability domains were drawn in a temperature - PCO2 diagram. The dependence of the reaction kinetics on PCO2, PO2 , or PN2 is discussed. In particular, the rate continuously decreases when PCO2 or PN2 increases, but it reaches a maximum as a function of PO2. For given partial pressures of gases and temperature the kinetics curves (conversion degree vs.time) may be interpreted by a "hampered"-diffusion mechanism