Densification Behaviour and Wear Performance of Brass-Based Composite Reinforced with SiO2 Nanoparticles: Switchable Water Pump Clutch Application

The friction disc and the impeller ring of a switchable water pump (SWP), having a similar principle to that of the wet clutch of an automobile, but it also exhibits a relatively low pressure, a high velocity and temperature. However, SWP possesses an inadequate friction coefficient that has a high tendency to result in the relative slip and severe wear of the counterparts. To acquire such a friction material with an improved friction coefficient and wear resistance to satisfy the new operating condition of SWPs, brass-based composites reinforced by SiO2 nanoparticles were successfully fabricated by the powder sintering in this study, and the influence of the mass fraction of SiO2 nanoparticles on the friction and wear behaviour of the composites was also discussed. The results show that the composite with an appropriate mass friction of SiO2 nanoparticles up to 5wt% exhibited a homogeneous microstructure. Meanwhile, the friction coefficient was raised to 0.23 with a wear volume reduced to 7.3x10(-5)mm(3), and the predominant wear mechanism changed from adhesive wear to abrasive wear, due to its enhancement of the densification level and the Vickers micro-hardness.