Study on corrosion failure mechanism of bearing outer ring and wear resistance of protective coatings

Abstract In this paper, the corrosion failure mechanism of bearing outer rings for railway freight car wheelset and the wear performance of coatings were systematically analyzed and tested. The results show that the microcells formed by martensite and Fe 3 C in the matrix structure accelerate electrochemical corrosion, which is mainly dominated by Cl -induced localized corrosion. The main components in the rust layer, γ-FeOOH/γ-Fe 2 O 3 , have a loose and porous structure, making it difficult to effectively block the penetration of corrosive media and forming a cycle of "corrosion-infiltrationrecorrosion". In the wear performance tests of different coatings, the weight loss rate of the epoxy coating after friction reaches 0.0616%, that of the phosphating film is less than 0.0019%, and although the thermal spray coating has a higher friction coefficient, its weight loss rate is close to zero, making it suitable for high-load and severe-wear scenarios.