Effect of Metal Ions on BSA Adsorption and Tribofilm Formation

The effects of Co ions and Cr ions on protein adsorption and tribofilm formation were studied by dissipative quartz crystal microbalance (QCM-D) and tribocorrosion experiments. In the presence or absence of metal ions, protein adsorption is all divided into two stages, and tribofilm is all produced after tribocorrosion. The difference is that Co ions reduce the adsorption of proteins by affecting electrostatic adsorption. Cr ions enhance the hydrophobic process, prompting protein aggregation on the metal surface, resulting in increased adsorption. When Co ions were added/not added, there was no significant change in the size of the tribofilm (about 10–20 μm) after tribocorrosion tests. However, after the addition of Cr ions, the size of the tribofilm formed by tribocorrosion was significantly increased (about 70  μm). This means that Cr ions not only increase the adsorption of proteins, but also promote the increase of the size of the tribofilm.