The pin on the disc friction tester was used to conduct the intermittent braking testing of train brake materials with a low-temperature environment simulation device at temperatures 20 °C, 0 °C, −10 °C, −20 °C, and −30 °C. The results show that intermittent braking presents different wear characteristics of braking materials at low temperatures. Under different ambient temperature conditions, the most volatile friction coefficient caused by intermittent braking happens at 0 °C, and the wear rate of brake materials reaches its maximum at 0 °C. The wear surface morphology of the brake pad material mainly includes scratches, furrows, adhesions, and abscission pits, while the surface of the brake disc material was dominated by scratches, furrows, and adhesions. With the decrease in temperature, the adhesion damage of the brake pad/disc material increases. At 0 °C, the brake pad material has crack damage.

A multi-functional friction and wear testing machine was used to test the pin disk wear of high-speed railway brake friction material under different disk temperatures (20 °C, 100 °C, and 200 °C) and different ambient humidities (55%, 95%). The test results show that the change in the disk temperature and different ambient humidities have significant effects on the frictional wear performance of the high-speed railway brake material. Under the conditions of 20 °C, 100 °C and 200 °C, the instantaneous friction coefficient and wear rate of the brake material decreased as the ambient humidity increased. The different ambient humidity caused severe surface damage to the brake materials, but the damage mechanisms were dramatically different. At constant temperature, the higher the ambient humidity, the lower the maximum equilibrium temperature of the disc.

The wear and fatigue behaviors of two newly developed types of high-speed railway wheel materials (named D1 and D2) were studied using the WR-1 wheel/rail rolling–sliding wear simulation device at high temperature (50 °C), room temperature (20 °C), and low temperature (−30 °C). The results showed that wear loss, surface hardening, and fatigue damage of the wheel and rail materials at high temperature (50 °C) and low temperature (−30 °C) were greater than at room temperature, showing the highest values at low temperature. With high Si and V content refining the pearlite lamellar spacing, D2 presented better resistance to wear and fatigue than D1. Generally, D2 wheel material appears more suitable for high-speed railway wheels.

Hybrids of fluorinated graphite/MoS₂ (FGr@MoS₂) were prepared via a hydrothermal method and used as lubricating additives to take full advantage of the synergy between FGr and MoS₂ in carbon-fiber-reinforced polymer (CFRP). The results show a 21.6% reduction in the friction coefficient compared to the neat sample when the CFRP was filled with 1.2 wt.% FGr@MoS₂ hybrids. The addition of 1.5 wt.% FGr@MoS₂ resulted in a 60.9% reduction in the wear rate compared to neat CFRP. For the 1.2 wt.% FGr@MoS₂-reinforced CFRP, the friction coefficient maintained a relatively steady value of approximately 0.46 at various temperatures, indicating frictional stability. However, the wear rate increased by 13.95% at 60 °C compared to that at room temperature. The interfacial bonding force between the FGr@MoS₂ hybrid and the matrix, as well as the adhesive force with the surface of the counterpart ball, is improved, caused by the heterostructure of FGr@MoS₂, resulting in enhanced mechanical properties and formation efficiency as well as the transfer film on the surface of the counterpart ball. The results suggest that an FGr@MoS₂ micro-nano structure is a promising additive to be applied in polymer tribology.

The friction and wear tests of high-speed railway braking materials for a variety of braking speeds (600, 400, and 200 rad/min) at 65% and 98% RH RH (RH: relative humidity) were carried out utilizing a friction-testing machine and humidity generator. The research results indicate that braking speeds and ambient humidity have a prominent influence on the friction and wear characteristics of high-speed railway braking materials. At 65% and 98% RH, the lower the braking speed, the lower the wear rate, and the better the wear resistance property of the braking material. Furthermore, at 600 rad/min, the wear rate of the braking material at 98% RH was smaller than that at 65% RH. However, at 200 rad/min, the wear rate of the braking material at 98% RH was greater compared to that at 65% RH. Concretely, at 600 rad/min, compared with 65% RH, the wear rate to the brake disc at 98% RH was reduced by about 9%, and the brake pin decreased by about 6%. However, at 200 rad/min, compared to 65% RH, the wear rate to the brake disc at 98% RH increased by about 39%, and the brake pin increased by about 37%.