ZrO2-phosphates porous ceramic obtained via SPS-RS “in situ” technique: Bacteria test assessment

Abstract

Abstract The work presents an original way to obtain porous and mechanically strong (to 560 MPa) ZrO2 ceramics containing calcium phosphates, HAP (Ca10(PO4)6(OH)2) and TCP (Ca3(PO4)2), using SPS-RS technique. “In situ” formation of calcium phosphate phases (15 and 50 wt%) has been observed in the bulk of ZrO2 arising from solid-phase interaction of CaO and CaHPO4 mixture at SPS conditions (900–1300 °C). Temperature regime for “in situ” interaction was optimized in accordance with HAP and TCP stability investigations under conditions of oxidative annealing and SPS heating without ZrO2. Addition of a poreforming agent (carbon template) has been demonstrated to enhance the porosity of the ZrO2-phosphate ceramics. Effect of the poreformer amount (2, 5, 10 and 15 wt%) on the structural and mechanical properties of ceramics has been studied by the means of mercury porosimetry, low-temperature nitrogen sorption, microscopy, and other analytical techniques. Microbiological tests were performed to assess the efficiency of bacterial film formation on the samples of composite ceramics depending on the calcium phosphate content. Morphology of the biofilms and the relative surface they occupied on the ceramics were investigated using electron microscopy and image processing method based on local binary pattern (LBP) classifier. Suggested SPS-RS method provides porous and mechanically strong ZrO2-phosphate composite ceramics containing biocompatible components HAP and TCP, which can be prospective for bone-ceramic implants for bone tissue recovery.