Electrochemical corrosion behavior and passivation mechanism of tantalum in simulated human body fluid environment

This study investigated the electrochemical corrosion behavior and passivation mechanism of tantalum under simulated conditions of the human hip joint. The analysis reveals a series of corrosion characteristics of tantalum in simulated body fluid. Additionally, the study demonstrates that the passivation film on tantalum exhibits n-type semiconductor properties, primarily controlled by oxygen ion vacancy defects, with calculations of oxygen vacancy concentrations at different film-forming potentials. XPS analysis confirms that the surface composition of the passivation film mainly comprises Ta₂O₅ and tantalum suboxides (TaO_x), and quantifies a linear relationship between passivation film thickness and film-forming potential. Finally, by integrating the point defect model (PDM), the study explores into the growth mechanism of the passivation film, derives particle-level reaction processes, and calculates the concentration of point defects within the passivation film formed under the passivating potential in simulated fluid.