The running-in mechanisms of binary brass studied by in-situ topography measurements

We found that a significant reduction in friction during running-in occurs only at a small range of pressure (2.4-2.9 MPa). We suggest that two main mechanisms are favorable for running-in. The first mechanism is the presence of ZnO in the near-surface region of the wear track, which acts as lubrication and reduces the friction. The second mechanism is the presence of C/CHX within the first 200 nm of the pin which acts as a passivation layer and thus keeps the transfer film thin and stable.