Abstract: The tribological properties of water-soluble borate are evaluated using four-ball machine and HQ-1 block-on-ring tribotester. The rubbed surface is investigated using X-ray photoelectron spectroscopy and electronic probe analysis. The tribological test results show that the water-soluble borate has good lubricating performance and lad-carrying capacity. The surface analyses show that the content of element boron, nitrogen and sulphur in wear scar surface is well-distributed. The borate reacted with the metal surface in friction process and produced a complex film composed of organic nitrogen, boric aced, boron oxide, iron disulfide, ferrous sulfate and tribopolymer, which is effective on improving the antiwear, friction-reduction and load-carrying capacity of water-based fluid.

Key words: Antiwear mechanism, Borate, Tribological property