Abstract
We prepared highly <001>-textured Ca3Co4O9 ceramics by the reactive templated grain growth (RTGG) method using a CdI2-type structured Co(OH)2 platelet as a reactive template. The Co(OH)2 particles with aspect ratio ∼5 were wet-mixed with a complementary reactant CaCO3 and the particles were uniaxially aligned by tape casting. Upon heat treatment, Ca3Co4O9, or misfit layer structured [Ca2CoO3]0.62[CoO2] was in-situ formed with maintained orientation of Co(OH)2. The analytical investigation revealed that the topotactic conversion from a Co(OH)2 platelet into a platelike Ca3Co4O9 grain through spinel-type Co3O4 phase.
