Lithium-Calcium Greases Having Carbon Nanotubes and Aluminum Oxide Base Nanoadditives: Preparation and...

Area of Science:

• Materials Science
• Tribology
• Nanotechnology

Background:

• Lithium-calcium grease (LCG) is a widely used lubricant.
• Enhancing grease properties for extreme pressure applications is crucial.
• Nanomaterials offer potential for lubricant additive development.

Purpose of the Study:

• To investigate the impact of multiwall carbon nanotubes (MWCNTs) and aluminum oxide nanoparticles (Al2O3) on LCG characteristics.
• To determine the optimal concentration of nanoadditives for improved grease performance.
• To evaluate the tribological and thermal properties of nanolubricants.

Main Methods:

• Preparation of LCG with varying concentrations (2-8 wt%) of MWCNTs and Al2O3.
• Characterization of grease properties: dropping point, consistency, thermal conductivity, and tribological behavior (wear, friction, welding point) using a four-ball tribometer.
• Morphological analysis of additives and nanogrease via X-ray diffraction and transmission electron microscopy.
• Assessment of worn surfaces using scanning electron microscopy.

Main Results:

• The addition of Al2O3 and MWCNTs significantly enhanced LCG properties.
• A 4 wt% concentration of Al2O3 and MWCNT resulted in the lowest wear scar diameter and friction coefficient.
• Significant improvements were observed in welding point (+26%), dropping point (+32%), and thermal conductivity (+75%) with nanoadditives.
• Nanoadditives demonstrated a striking enhancement of the lubricating effect.

Conclusions:

• Nanoadditives, specifically MWCNTs and Al2O3, can substantially improve the performance of lithium-calcium grease.
• The optimized 4 wt% nanoadditive formulation offers superior lubrication characteristics for extreme pressure conditions.
• This research presents a promising advanced lubricant for demanding industrial applications.