Lemin Sun

Comparative Study on Wear Behaviors of Metal-Impregnated Carbon Material and C/C Composite Under Electrical Sliding

In this article, the wear behavior of metal-impregnated carbon materials (MIC) and carbon–carbon composites(C-C) was investigated using a self-made current-carrying wear tester producing an electrical current of 40–160 A and a contact speed of 10–50 m/s. The worn surfaces were observed by means of scanning electron microscopy (SEM), and a new parameter for current-carrying stability that describes the stability of the current as a function of wear was proposed. The results indicate that the wear rate of both materials tested increased with either an increase in electrical current or contact sliding speed. Compared to the metal-impregnated carbon material, the C-C composite material not only displayed superior wear resistance but superior current-carrying stability as well. With increasing electrical current, the current-carrying stability of the two materials changed within a narrow range at a speed of 20 m/s and decreased at a speed of 50 m/s. Wear failure was mainly due to electrical erosion occurring at high speed and high current.

Study of the Friction and Wear of Electrified Copper against Copper Alloy under Dry or Moist Conditions

The frictional and wear characteristics of electrified copper sliding against a QCr0.5 copper alloy under moist and dry conditions were investigated utilizing a special pin-on-disc apparatus. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to observe the morphology of the copper pin contact surface and analyze its compositions, respectively. The results indicate that the wear rate and frictional coefficient of the copper are reduced as a result of the cooling and lubricating effect of water compared with dry sliding condition. However, both the frictional coefficient and wear rate of the copper material increases with an increase in electrical current under either moist or dry conditions and the frictional coefficient varies within narrow limits under wet conditions. In addition, there is a greater amount of oxygen associated with the surface under wet conditions than dry.

Research on Frictional Wear Properties of C/C Composite with Electric Current

Using C/C composite and chrome bronze as a friction couple, the frictional wear properties of C/C composite with electric current is studied in this paper. The results have shown that current, velocity and load are important factors to affect the frictional wear properties of C/C composite with electric current. The coefficient of friction and the wear rate increase with the increase of velocity when the electric current is constant of 100A. The coefficient of friction increases but the wear rate decreases with the increase of load when the electric current is constant at 100A. The coefficient of friction decreases but the wear rate increases with the increase of current when the load is constant of 80N. Comparing with no electric current, the coefficient of friction of C/C composite with electric current decreases but the wear rate of that increases obviously. The wear mechanism of C/C composite is mainly of electric wear caused by arc erosion under the condition of current-carrying.

The Study of Arc Rate, Friction, and Wear Performance of C/C Composites in Pantograph–Catenary System

A series of tests on arc rate, friction coefficient, and wear rate of electrical current collectors sliding against overhead contact wires under different conditions was carried out on a high-speed friction and wear testing machine with a pin-on-disc configuration. The worn surface morphology and composition were examined using a scanning electron microscope and energy dispersion spectrum analyzer, respectively. The effects of current, velocity, and load on the arc rate, friction coefficient, and wear rate of C/C composites/QCr0.5 couples were investigated, and the influence mechanism of test parameters on C/C composites was explained. It is concluded that the wear rate increases with an increase in current and velocity and has a decreasing trend with the increase in load. The friction coefficient increases with an increase in velocity and load. The arc rate of C/C composites/QCr0.5 couples increases with an increase in current and velocity. Under the condition of the same current and velocity, when the load is 70 N, the arc rate is the lowest.

Tribo-Electric Behaviors of Copper Under Dry Sliding Against Cu-Cr Alloys

The tribological and electrical conduction behaviors of copper under dry sliding against copper-chromium alloys were investigated on the basis of simulation tests. The experimental results show that electrical current and tribological parameters have combined effects on both electrical conduction ability and tribological properties. High sliding velocity and electrical current density deteriorate both the tribological and electrical conduction properties in tribo-electrical sliding system. In the end, the worn surface analysis suggests that friction, resistance heat and electrical arc spoiling are the main factors to influence the tribological and electrical conduction properties.Copyright