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.