Adhesion of a chemically deposited monetite coating to a Ti substrate

Monetite is a promising biomaterial for restoring the function of the compromised skeletal structures due to its superior osteoconductive and resorption properties. However, its potential as a coating for orthopaedic implants in load bearing applications has not yet been investigated. The aim of this study was to prepare monetite coating on Ti substrate in mild conditions, which may allow incorporation of protein-based drugs during the coating deposition. Coatings were prepared using chemical deposition of monetite on Ti substrate in acidic conditions at 75 °C for 24 h. Coatings were characterised by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Adhesion of the coatings to Ti substrate was measured using tensile tests. EDS confirmed the calcium phosphate nature of the coating and XRD and FTIR confirmed the monetite phase of the coatings. SEM revealed that the coatings were formed of densely packed plate-like monetite crystals, with the crystal size approximately 20 × 10 × 5 μm. Adhesion tests showed cohesive failure of the monetite coatings and the tensile strength of the coating was in the range of 15.43 ± 0.20 MPa. Mechanical tests showed that monetite coatings were stable and could be considered for use with Ti orthopaedic implants.