Flow behaviour of lubricants largely depends on their rheological properties which in turn strongly influence their lubrication capabilities and ultimately the machine life. Modern chemistry plays a great role in the synthesis of nano-additives that help in enhancing the rheological and tribological properties of the lubricants. In the present study, the rheological and tribological studies of $$\hbox {MoS}_{2}$$ nanofluids are presented in order to determine their flow behaviour and lubrication capabilities. For studying the effect of $$\hbox {MoS}_{2}$$ nanoparticles on the flow behaviour and lubrication capabilities of lubricants, two commercially available blended synthetic engine oils of SAE grades 5W-40 were selected. $$\hbox {MoS}_{2}$$ nanoparticles were synthesized by hydrothermal methods. Surface modification of the synthesized $$\hbox {MoS}_{2}$$ nanoparticles was performed before blending them with the base lubricants in 0.1, 0.15 and 0.2% concentrations. Standard ASTM and IS procedures were used to determine physicochemical properties and tribo-performance behaviour of oils, respectively. The rheological parameters of $$\hbox {MoS}_{2}$$ nanofluids were determined using a rheometer. The study reveals that tested $$\hbox {MoS}_{2}$$ nanofluids behaved as non-Newtonian lubricants with shear thinning behaviour at all tested temperatures and exhibited viscoelastic behaviour at small-shear rates. As a result of this anti-wear property showed a significant enhancement up to 20% for 0.2% $$\hbox {MoS}_{2}$$ indicating better anti-wear properties of $$\hbox {MoS}_{2}$$ nanofluids. However, a marginal reduction in friction for the tuning of 4% observed for 0.2 wt% of $$\hbox {MoS}_{2}$$ nanoparticles in the tested lubricants indicates that finished products have little scope to improve anti-friction properties under the influence of the already present additives.

中文翻译：

---

$$\hbox {MoS}_{2}$$MoS2 的流动行为和润滑能力研究

润滑剂的流动行为很大程度上取决于它们的流变特性，而流变特性反过来又会强烈影响它们的润滑能力并最终影响机器寿命。现代化学在纳米添加剂的合成中发挥着重要作用，有助于提高润滑剂的流变学和摩擦学性能。在本研究中，提出了 $$\hbox {MoS}_{2}$$ 纳米流体的流变学和摩擦学研究，以确定它们的流动行为和润滑能力。为了研究 $$\hbox {MoS}_{2}$$ 纳米颗粒对润滑剂流动行为和润滑能力的影响，选择了两种 SAE 等级 5W-40 的市售混合合成发动机油。$$\hbox {MoS}_{2}$$ 纳米颗粒是通过水热法合成的。在将合成的 $$\hbox {MoS}_{2}$$ 纳米颗粒与基础润滑剂以 0.1、0.15 和 0.2% 的浓度混合之前，对其进行表面改性。标准 ASTM 和 IS 程序分别用于确定油的物理化学特性和摩擦性能。$$\hbox {MoS}_{2}$$ 纳米流体的流变参数使用流变仪测定。研究表明，经过测试的 $$\hbox {MoS}_{2}$$ 纳米流体在所有测试温度下都表现为非牛顿润滑剂，具有剪切稀化行为，并在小剪切速率下表现出粘弹性行为。由于这种抗磨损性能在 0.2% $$\hbox {MoS}_{2}$$ 显示出高达 20% 的显着增强，表明 $$\hbox {MoS}_{2 具有更好的抗磨损性能}$$ 纳米流体。然而，