Wollastonite ceramics with bimodal porous structures prepared by sol-gel and SPS techniques

In this work, we suggest a novel synthetic route combining sol-gel and SPS for the fabrication of porous ceramics based on wollastonite with bimodal pore size distributions (100-500 nm and 1-500 mu m) and high mechanical strength (Young's modulus from 72.5 to 172 MPa). We studied peculiarities in the formation of the biporous silicate framework using two types of pore forming additives (templates) of various natures, shapes and sizes, introduced during different stages of sol-gel and SPS synthesis: organo-nonorganic (polymer latex of "core-shell" type) and nonorganic (carbonaceous filler). The influence of carbonaceous template content (5% or 25%) on the structural and mechanical properties of ceramics synthesized by spark plasma current was described. The original approach presented here provides formation of wollastonite ceramics with high mechanical strength and a biporous structure that is similar to the texture of bone tissue and is capable of executing its main functions. The obtained ceramics meet all the requirements of the bioceramics class demanded by modern medicine.