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The formation mechanism of K2Ti2O5 was investigated with Ti O2 microparticles and nanoparticles as precursors by the thermogravimetric(TG) technique. A method of direct multivariate non-linear regression was applied for simultaneous calculation of solid-state reaction kinetic parameters from TG curves. TG results show more regular decrease from initial reaction temperature with Ti O2 nanoparticles as raw material compared with Ti O2 microparticles, while mass losses finish at similar temperatures under the experimental conditions. From the mechanism and kinetic parameters, the reactions with the two materials are complex consecutive processes, and reaction rate constants increase with temperature and decrease with conversion. The reaction proceedings could be significantly hindered when the diffusion process of reactant species becomes rate-limiting in the later stage of reaction process. The reaction active sites on initial Ti O2 particles and formation of product layers may be responsible to the changes of reaction rate constant. The calculated results are in good agreement with experimental ones.
The formation mechanism of K2Ti2O5 was investigated with Ti O2 microparticles and nanoparticles as precursors by the thermogravimetric (TG) technique. A method of direct multivariate non-linear regression was applied for simultaneous calculation of solid-state reaction kinetic parameters from TG curves. TG results show more regular decrease from initial reaction temperature with Ti O2 nanoparticles as raw material compared with Ti O2 microparticles, while mass losses finish at similar temperatures under the experimental conditions. From the mechanism and kinetic parameters, the reactions with the two materials are complex consecutive processes , and reaction rate constants increase with temperature and decrease with conversion. The reaction actives could be significantly hindered when the diffusion process of reactant species becomes rate-limiting in the later stage of reaction process. The reaction active sites on initial Ti O2 particles and formation of product layers may be respondent sible to the changes of reaction rate constant. The calculated results are in good agreement with experimental ones.