Reaction of Strontium Carbonate with Anatase and Rutile

The kinetics of the solid‐state reaction of strontium carbonate with anatase and rutile in air and carbon dioxide were studied by use of a thermobalance. The product was single‐phase SrTiO 3 in all cases. The relation between fraction reacted and time was fitted to the Jander equation and to the Carter equation for both anatase and rutile. For anatase the rate constant in carbon dioxide did not differ from that in air. The reaction rates for rutile in air and in carbon dioxide were ⅓ and ⅛ that for anatase, respectively. The In k vs 1/ T relation for anatase gave two straight lines with different slopes having a break point at ∼820°C in both air and carbon dioxide. The Jander activation energies for anatase in the higher and lower temperature regions were ∼340 and ∼290 kj · mol −1 , respectively, and those for rutile in air and carbon dioxide were 340 and 390 KJ · mol −1 , respectively.