Synthesis and properties of Zn and Zn–Mg-doped tricalcium phosphates obtained by Spark Plasma Sintering

Abstract

[EN] β-tricalcium phosphate (Ca(PO) or TCP) are essential biomaterials because of the chemical composition, high biocompatibility and osseointegration. However, their limited mechanical properties restrict their use to areas where high mechanical performances are not required. Spark Plasma Sintering (SPS) was selected out of the unconventional sintering methods in order to obtain high-density doped-TCP bioceramic materials. The main advantages of SPS are a high heating rate, low sintering temperatures and short residence times, producing bioceramics with full density and fine-grain microstructure. The main purpose was to design, obtain by SPS and characterize undoped β-TCP, 1ZnO-doped β-TCP and 1ZnO-1MgO codoped β-TCP (wt. %) bioceramics. All the obtained samples were visually semitransparent and mainly β-TCP was detected by X-ray analysis. Densification behavior was determined by Archimedes' method and microstructural features of the sintered specimens were analyzed by Field Emission Scanning Electron Microscopy (FE-SEM-EDX). The undoped and doped β-TCP bioceramics were mechanically characterized, specifically the modulus of elasticity and Vickers microhardness. The results are compared with equivalent samples obtained by conventional solid-state sintering (CS) reaction. A first study of biological behavior was carried out, specifically direct cell adhesion of MG-63 human osteoblast-like cells on the polished surfaces of β-TCP, 1ZnO-β-TCP and 1ZnO–1MgO-β-TCP dense samples were determined. The present study concludes that the SPS process together with the doping effect enhanced sinterability, mechanical and biological properties of Zn-TCP and Zn–Mg-TCP based materials.