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Journal of Thermal Spray Technology

, Volume 28, Issue 5, pp 893–903 | Cite as

Effect of Vacuum Hot Pressing on Plasma-Sprayed Molybdenum Coatings on Rail Vehicle Axle Steel

  • Chunming Liang
  • Min YuEmail author
  • Hao Ma
  • Hui Chen
Peer Reviewed
  • 52 Downloads

Abstract

Railway axles suffer severe friction damage during service. In this work, a pure molybdenum coating was prepared on EA4T axle steel by air plasma spraying and hot pressing to improve the steel lifetime. The phase composition, microstructure, hardness, and tribological properties of the coatings were characterized. The results showed that the Mo coating had typical lamellar structure with low porosity and oxidation. Hot pressing compacted the coating and improved the microstructure uniformity. The hardness of the Mo coating and its bonding strength with the substrate were increased after hot pressing under 60 MPa at temperatures ranging between 400 and 500 °C, due to reduced porosity and enhanced mechanical bonding between the coating and substrate. In addition, both the friction coefficient and wear loss of the Mo coating were lower than those of the EA4T steel, illustrating its lubricating effect. Observation of worn surfaces showed that the delamination wear of the Mo coating could be relieved after proper hot pressing due to the strengthened bonding between lamellae.

Keywords

air plasma spraying EA4T steel microstructure molybdenum coating rail vehicle tribological properties vacuum hot pressing 

Notes

Acknowledgments

This work was supported by the National Key and Program of China (2016 YFB 1100202).

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Copyright information

© ASM International 2019

Authors and Affiliations

  1. 1.Research Center of Sichuan Advanced Welding and Surface Engineering, School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengduPeople’s Republic of China

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