Tribological performance for an Mg alloy subjected to sliding at elevated temperatures: A comparison between Al2O3 and MoS2 nano additives in silicone oil-based lubricant

Magnesium (Mg) and its alloys are crucial for energy-efficient vehicles due to their strong and lightweight properties, necessitating high-temperature fabrication and lubrication to reduce oxidation, friction, and wear. This paper investigated the tribological performance of lubricating oil using different particles to a Mg alloy subjected to contact sliding in an open system at high temperatures up to 250 °C. The overall experimental results showed improved tribological performances by using the two types of nanoparticles / nanoparticle-clusters (concentration ≥ 0.5 wt%) compared with the base silicone oil. The mechanisms by which the two types of nano lubricants improved the tribological performance are different. Al2O3 particles provided a more stable Al-rich anti-wear surface at higher temperatures in the range of 200–250 °C, while a tribo-chemical reaction film was formed with MoS2 additives, generating MoO3 and MgSO4. It is generally concluded that Al2O3 has more positive effect in terms of reduced coefficient of friction and wear rate as comparison to MoS2.