Tribological of Eu-doped WO₃ coated with SiO₂ transfer film formation on sliding surface

ABSTRACT

Europium nitrate, ammonium tungstate and hexadecyl trimethyl ammonium bromide were used, and Eu-doped WO₃ (WO₃:Eu³⁺) nanopowder was synthesized by the micro-emulsion method. Tetraethyl silicate was hydrolysed into SiO₂ and WO₃:Eu³⁺ nanopowder coated with SiO₂ (SiO₂/WO₃:Eu³⁺) was obtained. The microstructure and morphology of the prepared nano-SiO₂/WO₃:Eu³⁺ powders were characterized by XRD, SEM, TEM and HRTEM. Results showed that the prepared nano-SiO₂/WO₃:Eu³⁺ powders composed of WO₃ of monoclinic and SiO₂ of amorphous, which was spherical and granular, and the grain size reaches 50 nm. The tribological behaviour of nano-SiO₂/WO₃:Eu³⁺ as extreme pressure and anti-wear additive in the water-based fluid was studied by a four-ball machine. The results demonstrate that nano-SiO₂/WO₃:Eu³⁺ exhibits superior load-bearing capacity, anti-wear and anti-friction performance in water-based fluid, especially when the optimal concentration of nano-SiO₂/WO₃:Eu³⁺ is 0.4 wt-%. WSD, COF and wear volume of the nano-SiO₂/WO₃:Eu³⁺ decreased by 62.43%, 30.20% and 67.34%, respectively, compared with that of the water-based fluid.

KEYWORDS:

• Sliding wear
• micro-scale abrasion
• steel
• lubricant additives
• nanotribology
• tribofilm
• TEM
• XRD

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Thanks for the support of the major project of Nanjing Institute of Technology Innovation Fund (CKJA202201), the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology (ASMA202202)