Mechanism of Texture Development in Bi-0.5(Na,K)(0.5)TiO3 prepared by the Templated Grain Growth Process

The mechanisms of texture evolution in Bi-0.5(Na,K)(0.5)TiO3 (BNKT) prepared by the templated grain growth method are examined using platelike SrBi4Ti4O15 and Al2O3 powders and SrTiO3 and Al2O3 single crystals as templates. These templates give rise to a < 100 > texture in the BNKT matrix. The mechanism of texture evolution is dependent on the template species. When SrBi4Ti4O15 and SrTiO3 are used, a new grain (terrace) forms between the matrix and the template grains. The terrace has the same crystallographic orientation as the template. The terrace grows at the expense of the matrix grains, resulting in texture evolution. For the Al2O3 template, no terrace forms between the matrix and the template grains. Instead, the matrix grains directly attach to the template surface. The formation of a phase boundary with a specific orientation gives rise to texture evolution for this template.