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 its 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), 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.