Effect of Current on Friction and Wear Properties of QBe2.0 Brush Wire

The rotating conductive joint is a device that connects the fixed part and the moving part, which is used to transmit the current and signal. The traditional conductive slip ring transmits power and signal between the brush and the slip ring, which is widely used in aerospace and navigation fields, military fields, new energy resources and medical fields. In some working conditions, the slip ring has the advantages of better conductivity, better wear resistance, smaller friction coefficient, lower electrical noise and stronger resistance to arc erosion. Therefore, conductive rings and brushes are generally made of gold, silver, silver copper, platinum-iridium and so on. Although these precious metal materials have better wear resistance and smaller friction coefficient, the cost of gold and silver are much more expensive. Therefore, precious metals are generally used in high-end industries. Beryllium bronze is a kind of alloy with better comprehensive properties, better electrical conductivity. Besides, it is cheaper compared with precious metals. In the civil field, it is widely used in all walks of life. The current-carrying sliding between friction couples has important impacts on the tribological properties of conductive slip rings. Scholars and scientific research institutions have carried out a lot of work on the tribological properties and damage mechanism of conductive slip rings. The slip ring structure, material, brush wire coating, environment ware studied. the current deteriorated the contact conditions of ring and brush pairs. The wear was more complicated than that of ordinary friction pairs. At present, the damage mechanism of the brush wire and conductive slip ring V-groove/cantilever beam with current was still not clear, so it was necessary to carry out relevant research. This paper studied the influence of different current on the tribological properties and electrical contact properties of brush wire. By optical microscopy, scanning electron microscopy, white light interference three dimensional profilometer, energy dispersive spectrometer and x-ray diffractometer. influence of current on the friction and wear behavior of brush wire/slip ring current-carrying friction pairs was revealed. The relevant researches provided basic experimental data and theoretical support for the industrial application of conductive slip ring. The results showed that with the increase of current intensity, the average friction coefficient of friction pair was increased and the contact resistance was decreased. At the same time, the wear surface temperature of brush wire was increased and the average hardness was decreased. The resistance fluctuation was influenced by the contact area. The contact area increased with the increase of current. The contact stability increased with the increase of the contact area, which was beneficial to the resistance fluctuation. As a result, the resistance fluctuation was decreased with the increasing current. Under the combined effects of friction heat, resistance heat and arc heat, the oxidation wear of the brush wire wear surface was intensified. The wear loss and the roughness were increased. Arc erosions and melting spatterings were detected on the wear debris. The oxidation particles and the cracks were observed on the wear surface of the brush wire. With the increase of current intensity, the tribology properties of the friction pair were decreased. However, the contact stability and conductivity of the friction pair were improved.