Friction properties are significantly affected by third bodies (films formed on friction surfaces). However, the study of their composition and structure remains incomplete. For this reason, an organic composite railway brake shoe was tested at an initial braking speed of 125 km/h using a full-scale dynamometer. A third body with a thickness of ~120 μm was obtained, and its morphology and composition were analyzed using a multiple techniques. The results indicated that the third body had a layered structure. The upper surface was smoother than the lower surface. The carbon content on the upper surface decreased by 68.01%, and the iron content increased by 11.85 times in relation to that on the lower surface. Compared to the brake shoe, the iron content of the third body increased by 272.81%, and most of the iron was oxidized. Furthermore, the content of barium, calcium, and silicon decreased by more than 33%, and the crystalline structures of the inorganic filler materials, such as graphite and barium sulfate, were destroyed, with new crystalline structures appearing. Finally, the residual weight at 650 °C increased from 90.35% to 96.59%. This research could provide a reference for exploring the friction and wear mechanisms of organic composite railway brake shoes.

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Low-acrylonitrile nitrile butadiene rubbers (NBRs) are seriously degraded by No. 15 oil in the hydraulic system of aircraft. The present work aims to prepare rubber materials with excellent low-temperature and No. 15 aviation hydraulic oil resistance. Terpolymerization epichlorohydrin rubber (ECO) and lowacrylonitrile NBR were blended. The blends were vulcanized using peroxide.The effects of the ECO/NBR blending ratio on the oil resistance and lowtemperature, physical and mechanical, hot air aging, and ozone aging proper-