Macroscale Superlubrication Achieved with Shear-Thinning Semisolid Lubricants

Area of Science:

• Materials Science
• Tribology
• Nanotechnology

Background:

• Solid superlubricants require complex fabrication and controlled environments.
• Liquid superlubricants suffer from issues like creep, leakage, and corrosion.
• Existing superlubrication methods have significant practical limitations.

Purpose of the Study:

• To introduce a novel semisolid superlubrication material overcoming current limitations.
• To investigate the superlubricity mechanisms of subnanometer nanowires (SNWs).
• To develop a new class of semisolid gel lubricants with enhanced performance.

Main Methods:

• Development of semisolid subnanometer nanowires (SNWs) utilizing the shear-thinning effect.
• Testing SNWs with silicon nitride (Si3N4) and polytetrafluoroethylene (PTFE) tribo-pairs.
• Analysis of synergistic mechanisms including shear-thinning, adsorption membranes, and hydrodynamic effects.

Main Results:

• Achieved exceptionally low friction coefficients (0.008-0.009).
• Demonstrated stable superlubrication over 12 hours (>120,000 cycles) with a short running-in period (≈39 s).
• Successfully formulated semisolid gel lubricants with superlubricating properties by combining SNWs with base oils.

Conclusions:

• SNWs provide a robust solution for superlubrication, addressing limitations of current technologies.
• The synergistic combination of multiple mechanisms is key to achieving stable superlubricity.
• This work establishes a new category of semisolid gel lubricants with broad engineering potential.