The interface structure of medical Al₂O₃/Ti-13Nb-13Zr diffusion-bonded joints and their electrochemical corrosion behavior in simulated body fluid

The medical Al₂O₃/Ti-13Nb-13Zr (TNZ) alloy joints were achieved by diffusion bonding at 1175 °C/60 min/3 MPa. The interfacial microstructures of the bonded joints were investigated with a scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), and X-ray diffraction (XRD). The results show that the typical microstructure of the Al₂O₃/TNZ joint, which was obtained at 1175 °C for 60 min under a pressure of 3 MPa, was Al₂O₃ ceramic/TiAl layer + TiO₂ + Nb₂O₅ + AlNb₂/continuous Ti₃Al layer/acicular Ti₃Al + Ti (s,s)/TNZ substrate. Taking biomedical TNZ alloy as contrasting materials, the electrochemical corrosion behavior and corrosion mechanism of the alloys in Ringer’s simulated body fluid were investigated by potential potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) technique. The results show that the TNZ alloy exhibits good corrosion resistance due to smaller corrosion potential and smaller corrosion current density, bigger capacitive arc and wider passivation interval, and smaller corrosion pit compared with Al₂O₃/TNZ joints.