Tribological Performance of Inorganic Borate at Elevated Temperatures

Abstract

High-temperature tribology of steel components is typically characterized by high friction and excessive wear, which need to be addressed. In the present study, the tribological properties of an alkali borate were evaluated in a steel contact by ball-on-disc testing over a wide range of temperatures (600–800 °C) and loads. The compound exhibits good lubrication performance consistently throughout the whole testing range. On the rubbing disc, the formation of a tribofilm with a hierarchical structure is the determining factor for the friction-reducing and wear-inhibiting capacity of the lubricant. Worn surfaces were characterized by scanning electron microscopy (SEM) and cross-sectional observations of the tribo-interface were accomplished by scanning transmission electron microscopy (STEM) coupled with energy-dispersive spectroscopy (EDS). Secondary ion mass spectroscopy (SIMS) was employed to generate an elemental depth profile of the lubricated surface.

Keywords:

• High-temperature lubricant
• lubrication
• wear

Acknowledgements

The authors acknowledge the assistance of Dr. Mitchel Nancarrow and Dr. David Mitchell (UOW Electron Microscopy Centre) in microscopy work and Dr. Rong Liu (University of Western Sydney) for SIMS analysis.

Additional information

Funding

The study is funded by Australian Research Council Discovery Project (DP) 150103718. This study used the FEI NanoLab G3 CX, located at the UOW Electron Microscopy Centre, funded by the Australian Research Council (ARC) Linkage, Infrastructure, Equipment and Facilities (LIEF) grant (LE160100063) and JEOL JEM-ARM200F funded by the ARC Linkage, Infrastructure, Equipment and Facilities (LIEF) grant (LE120100104).