Wear-free sliding electrical contacts with ultralow electrical resistivity

Area of Science:

• Materials Science
• Tribology
• Electrical Engineering

Background:

• Sliding electrical contacts in devices like slip rings face issues such as high friction, wear, energy loss, and intermittent failures.
• Existing solutions are limited in addressing these inherent challenges in conductive interfaces.

Purpose of the Study:

• To achieve an ultralow-friction and wear-free state, termed structural superlubricity (SSL), for sliding electrical interfaces under ambient conditions.
• To explore the potential of diamond-like carbon (DLC) films in enhancing the electrical conductivity of these interfaces.

Main Methods:

• Experimental realization of structural superlubricity using single-crystal graphite flakes on metal films (Au, Ni).
• Deposition of thin diamond-like carbon (DLC) films on nickel alloy substrates.
• Density functional theory (DFT) simulations to investigate the mechanism of DLC film-enhanced conductivity.

Main Results:

• Achieved a state of structural superlubricity (SSL) with ultralow friction and wear-free performance between sliding electrical interfaces.
• DLC films (2-3 nm thick) on nickel alloys demonstrated lower resistivity than bare metals, improving conductivity.
• A prototype SSL slip ring exhibited excellent performance: ultralow friction, wear-free operation, and no intermittent failures.

Conclusions:

• Structural superlubricity (SSL) offers a viable solution for creating advanced electrical contact interfaces with superior performance.
• DLC films significantly enhance the conductivity of graphite-metal interfaces, paving the way for efficient electromechanical coupling.
• The developed SSL interfaces are suitable for applications demanding reliable conduction during sliding motion.