• • Nanocomposite additives reduce coefficient of friction (CoF) by 15%–60% and wear rate by 50%–90%, depending on operating conditions, enabling significant energy savings and extended equipment life in high-load (>1 GPa) and elevated-temperature (>100 °C) environments.
• • Core–shell architectures and surface functionalization effectively mitigate nanoparticle aggregation, maintaining stable tribological performance over extended test durations, which is critical for long-term industrial lubrication reliability.
• • Synthesis methods including hydrothermal, sol–gel, chemical deposition, and microwave-assisted processes provide tunable control over particle size, morphology, and surface chemistry, directly influencing lubrication behavior and enabling tailored additive design.
• • Nanocomposites exhibit multifaceted lubrication mechanisms—physical adsorption layers, tribochemical reaction films, microbearing effects, and worn-surface restoration—allowing adaptation to boundary and mixed lubrication regimes, outperforming single-component additives.