Friction and wear properties of foam ceramic/metal bi-continuous phase composites under continuous braking conditions

In order to solve the overheating failure problem of mechanical brakes of special tracked vehicles, SiC/Cu and SiC/Fe bi-continuous composites were prepared by squeeze casting method. The friction and wear properties of the two composites under continuous emergency braking and continuous high temperature braking conditions were studied. The variation of friction coefficient, temperature and wear rate was analysed by means of scanning electron microscopy (SEM), X-ray energy dispersive spectrometry (EDS) and 3D profiler, and the wear mechanism was described. The results show that in the continuous emergency braking test, the contact surface experiences the process of tribo-film formation and interlayer fracture.Friction coefficient decreases slightly with the increase of joining times and tends to be stable. In the first 40 joining, the wear rates of SiC/Cu and SiC/Fe friction pairs decrease overall. During 40-60 joining, the adhesion wear, oxidation wear and fatigue wear of the SiC/Cu friction pair are aggravated, and the wear rate increases, while the wear rate of the SiC/Fe friction pair is mainly abrasive wear, and the wear rate is low. In the continuous high temperature braking test, the friction coefficient increases gradually and the braking time decreases gradually in the first six joining. After the sixth joining, the adhesion wear and fatigue wear in the edge area of the friction pair result in the decrease of the torque, and the friction coefficient and braking time both show a trend of decrease at first and then increase. In the process of continuous high temperature braking, severe adhesive wear is the main factor. The wear rates of SiC/Cu and SiC/Fe friction pairs increase with the increase of joining times.