Mechanical, electrochemical, and biological properties of YSZ-Mo: A new class of bio-composites

Abstract

Polycrystalline tetragonal zirconia (3YTZP) has high strength and fracture toughness (K1C) among the other ceramics. However, this amount is still low compared to metals, limiting the use of these monolithic- parts. This study explores the effect of molybdenum on the mechanical, electrochemical, biological, and antibacterial properties of 3Y-TZP-based composites. Three samples of YSZ, YSZ-10wt.%Mo, and YSZ-20wt.%Mo were fabricated by the SPS method at 1450 °C. The microstructure of the mentioned bio-composites was examined by FESEM and XRD analysis. Three-point flexural strength, fracture toughness test, and Vickers microhardness test were also performed. YSZ-10Mo and YSZ-20Mo samples were subjected to Tafel polarization and electrochemical impedance spectroscopy (EIS) analysis. MTT assay was also used to assess the compatibility of the samples with G-292 cells. The antibacterial behavior of the specimens was assessed by the shake flask test. Microstructural results proved the complete densification of the samples. A rise in the molybdenum content slightly decreased the flexural strength (from 1185 ± 52 MPa for YSZ to 841 ± 63 for YSZ-20Mo) and hardness (from 13.35 ± 0.41 GPa for YSZ to 8.10 ± 0.24 GPa for YSZ-20Mo). However, the opposite behavior was observed for the fracture toughness of the samples (from 7.25 ± 0.67 MPa.m1/2 for YSZ to 14.90 ± 0.32 MPa.m1/2 for YSZ-20Mo). The corrosion test indicated the excellent corrosion resistance of the YSZ-10Mo composite. Enhancement of the molybdenum content had a destructive effect on the corrosion resistance of the composites. The results of the MTT test proved the excellent biocompatibility of the samples. An increment in Mo content also remarkably improved the biocompatibility and antimicrobial activity of the YSZ-20Mo sample.