Abstract

The present work focused on the extreme pressure characteristics of different grades of polyalphaolefins (i.e., PAO 4, PAO 6, PAO 40, and PAO 100) with LaF₃ nanoparticles as an additive. The LaF₃ nanoparticles were synthesized by the sol-gel method and modified with oleic acid. The synthesized nanoparticles were characterized with various analytical tools, viz. X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Varying doses (0.025–0.15 wt%) of synthesized nanoparticles were blended in all PAOs to prepare nanolubricants. The extreme pressure (EP) properties of nanolubricants were measured using a four-ball tester as per ASTM D2783 to find the last nonseizure load (LNSL), initial seizure load (ISL), just before weld load (JBWL), weld load (WL), and load wear index (LWI). The results revealed that the incorporation of LaF₃ nanoparticles efficiently enhanced the EP properties of all PAOs. However, 0.15 wt% of additive was the optimum dose in all PAOs, demonstrating the best EP behavior; that is, the highest LWI and lowest wear scar diameter (WSD) at ISL and JBWL. Numerous characterization techniques such as scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and scan probe microscopy (SPM) were adopted to investigate the probabilistic rationale for the improvement in EP properties.

摘要

目前的工作重点是不同等级的聚α烯烃（即PAO 4、PAO 6、PAO 40 和PAO 100）以LaF ₃纳米粒子作为添加剂的极压特性。LaF ₃纳米粒子通过溶胶-凝胶法合成并用油酸修饰。合成的纳米粒子用各种分析工具进行表征，即。X 射线衍射 (XRD)、高分辨率透射电子显微镜 (HR-TEM)、傅里叶变换红外光谱 (FTIR) 和 X 射线光电子能谱 (XPS)。将不同剂量（0.025-0.15 wt%）的合成纳米颗粒混合到所有 PAO 中以制备纳米润滑剂。根据 ASTM D2783 使用四球测试仪测量纳米润滑剂的极压 (EP) 性能，以找到最后的非咬合载荷 (LNSL)、初始咬合载荷 (ISL)、焊接载荷 (JBWL)、焊接载荷 (WL) ) 和负载磨损指数 (LWI)。结果表明，掺入 LaF ₃纳米粒子有效地增强了所有 PAO 的 EP 特性。然而，0.15 wt% 的添加剂是所有 PAO 中的最佳剂量，表现出最佳的 EP 行为；即 ISL 和 JBWL 处的最高 LWI 和最低磨痕直径 (WSD)。采用多种表征技术，如扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDS) 和扫描探针显微镜 (SPM) 来研究 EP 性能改善的概率原理。