Preparation, characterization, tribological and lubrication performances of Eu doped CaWO4 nanoparticle as anti-wear additive in water-soluble fluid for steel strip during hot rolling

Abstract

Citric acid-synthesized Eu-doped CaWO4 (CaWO4:Eu3+) nanoparticles in acidity (pH = 1) and alkalinity solutions (pH = 10) were analyzed by SEM, TEM, XRD, and Raman. The tribological and hot rolling lubrication properties of nano-CaWO4:Eu3+ as anti-wear additives in water-based rolling fluid were investigated. Results showed that CaWO4:Eu3+-pH = 10 has excellent load-carrying capacity, wear-resistance and friction-reducing properties in water-based rolling fluid, particularly in the bestconcentration was 0.5 wt%. The WSD value is decreased from 0.62 to 0.39 mm and the COF value is reduced from 0.092 to 0.070, which attributes to the formed tribofilm (~30 nm) on the worn surface is composed of Fe2O3, CaO, WO3 and Eu2O to avoid direct contact with the metals during hot rolling, thus reducing the friction coefficient and the oxide scale.