Preparation, characterization, tribological and lubrication performances of Eu doped CaWO_4 nanoparticle as anti-wear additive in water-soluble fluid for steel strip during hot rolling

摘要

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 best concentration 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 (similar to 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.