The formation mechanism of K

2

Ti

2

O

5

was investigated with TiO

2

microparticles and nanoparticles as precursors by the thermogravimetric (TG) technique. Amethod of directmultivariate non-linear regression was applied for simultaneous calculation of solid-state reaction kinetic parameters fromTG curves. TG results showmore regular decrease from initial reaction temperature with TiO

2

nanoparticles as raw material compared with TiO

2

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 TiO

2

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.