Crystal growth of potassium titanates in the system K₂O-Fe₂O₃-TiO₂

The system K₂O-Fe₂O₃-TiO₂ was investigated to find the condition in which various kinds of potassium titanates crystals having cage, tunnel and layered structures, respectively can be grown. When KNO₃, TiO₂ and Fe(NO₃)₃9H₂O were used as the starting materials, K_x(Fe, Ti)₆O₁₃ and K_x(Fe, Ti)₈O₁₆ were readily grown in the shape of fibers. The thermal decomposition stage is responsible for the formation of fibrous crystals with the desirable size and aspect ratio. K_2.3Fe_2.3Ti_5.7O₁₆ having a layered structure was synthesized and grown in the shape of platelet. The compound belonged to the orthorhombic Cmcm symmetry and had the lattice parameters of a = 0.3796 nm, b = 1.5735 nm and c = 0.2964 nm. The potassium ion which is located between the layers could be frequently replaced by an other alkali ions by intercalation swelling. The fibrous crystals of K_1.6Fe_1.6Ti_6.4O₁₆ could grown in the size of 16 mm X 0.2 mm, when a K₂MoO₄-MoO₃ flux was used 1300° C for 10 h. Its electric conductivity was in the range of 10⁰-10^-4 ohm^-1 cm^-1 measured at frequencies of 50 kHz to 10 MHz.