Study on the formation and growth of potassium titanate whiskers

In this paper, K2Ti2O5 single crystals, K2Ti4O9 whiskers and K2Ti6O13 whiskers are synthesized form the anatase-K2CO3 starting materials by the heating calcination and the corresponding morphologic and structural evolution of products are observed. After dissolving non-crystalline hydrosoluble products contained in sinters, the morphologic difference between the original sinter and the whiskers in it shows the sinter microstructure. The further analysis to crystal components in sinters and to the phase diagram proves that K2Ti4O9 whiskers are firstly formed in K2Ti2O5 crystals and there only exists the phase transformation from K2Ti4O9 whiskers with layered crystal structure to~K2Ti6O13 whiskers with tunnel crystal structure. The K2O-rich liquid melt generated from K2Ti2O5 crystals (/and K2Ti4O9 whiskers) coats on the surface of K2Ti4O9 whiskers (/and K2Ti6O13 whiskers), which makes the sinters taking on the layer-by-layer structure (/and the bunch structure). The formation and growth of whiskers is dictated by the K2O-rich non-crystalline hydrosoluble melt generated in phase transformations from solid to liquid-solid and its split effect induced by the orientation melting. A generalized “liquid melt inducing” mechanistic model explaining the formation and growth of potassium titanate whiskers was proposed.