Reactive Spark Plasma Synthesis of Porous Bioceramic Wollastonite

Abstract

A method was proposed for reactive spark plasma synthesis (R-SPS) of a porous (Ssp = 12.7–8.56 m2/g) and structurally strong (σcomp = 201.1–393.2 MPa) bioceramic composite material based on wollastonite (CaSiO3) containing 20 wt % hydroxyapatite (HAP). In this method, the precursor is an amorphous composite that is based on a mixture of xonotlite (Ca6Si6O17 · 2OH) with HAP and a pore-forming agent and is prepared by the sol–gel (template) synthesis. The originality of the method consists in the formation of crystalline ceramic wollastonite by the transformation of its hydrated form, xonotlite, under spark plasma heating conditions. The densification dynamics, phase formation, and microstructural changes of the formed CaSiO3/HAP ceramic at various (500–900°C) R-SPS temperatures were studied by XRD, TGA/DTA, SEM, BET method, and porosimetry. Microbiological evaluation of the efficiency of the formation of Pseudomonas aeruginosa bacterial films on the surface of samples of the produced CaSiO3/HAP ceramic was performed, in particular, in comparison with a noncomposite material in the absence of HAP. The proposed R-SPS method ensures the creation of a porous, structurally strong composite ceramic containing a biocompatible component (HAP). This ceramic can be promising for producing ceramic bone implants for bone defect restoration.