Fabrication of <001>-oriented apatite ceramics using a non-topochemical reactive α-tristrontium phosphate template

Textured ceramics are generally fabricated by reactive-templated grain growth using a template material with a suitable anisotropy and topochemical relationship to the target ceramics. We have previously synthesized hexagonal plate-like α-tristrontium phosphate (α-Sr3(PO4)2; α-TSP) single crystals with no topochemical relationship to the apatite system. In the present study, we focused on using the facets of α-TSP particles as nucleation sites for textured apatite, and fabricated <001>-oriented strontium fluoroapatite (Sr10(PO4)6F2; SrFAp) through a reaction between aligned α-TSP platelets and SrF2. The SrFAp phase was formed with a preferred c-axis orientation at 900°C. Sintering in an F-containing atmosphere led, moreover, to fabrication of textured SrFAp ceramics with a high ratio of conversion into apatite. In this way, textured polycrystalline ceramics with no topochemical relationship to the template material can be fabricated through reactive-templated grain growth using the facets of the template particles as nucleation sites.