Research On The Wear And Friction Properties Of Cu/QCr0.5 Couples Under Electrical Current

The test was carried out on the HST-100 pin-on-disc tribo-tester with Cu/QCr0.5 couples, which simulated working conditions of the pantograph-wire system used in electric railway. The effects of current, loading and speed on friction and wear properties were investigated by orthogonal experiment. The differences in the friction and wear properties with and without current were studied. Single-factor tests were conducted to investigate the relationship between the pin surface temperature and the friction and wear properties, arc energy. With the help of SEM and EDS, the morphologies of worn surface of the pin were examined, in order to study the tribological mechanism under different parameters.According to the orthogonal experiment, the current is the most notable factor affecting the friction and wear properties of this couple under the conditions of electrical current, and followed by load and speed. Compared with non-current conditions, the friction coefficient declined and the wear rate of the couple was much higher at the same loading and different velocities, and in the same under the conditions of the same velocities and different loadings. What's more, with the increasing current, the friction coefficient decreased, while the wear rate was gradually increasing.The temperaturverlauf of the pin specimens isn't the same under different parameters. But there would be a sharp increase in the first, and then gently change. And the steady-state surface temperature value is not the same under different parameters. At the same loading and velocity, the pin surface temperature increased, and so done the wear rate, while the friction coefficient decreased. At the same current and velocity, the relationship between temperaturverlauf and the friction and wear properties is more complex, and the sample surface temperature reached the maximum at the loading of 0.26MPa. Under the conditions of the same current and loading, as the pin surface temperature increased, the friction coefficient, but the wear rate increased. Also, arc energy is closely related to the sample surface temperaturverlauf, which can be concluded from the test.Combination of the SEM images of the worn surface, adhesive wear was the dominant mechanism without current. But under the current conditions, there was a large number of adhesion wear and plastic flow traces on the sliding surfaces. And a few melting or arc pit traces can be observed. And the cracks can be also observed due to the role of thermal stress generated in Instantaneous and concentration high temperature of arc. And the EDS of the worn surface indicated that oxidation took place in the friction process. In a word, adhesive wear, oxidative wear and electrical wear were the dominant mechanism.