Tuning friction force and reducing wear by applying alternating electric current in conductive AFM experiments

Area of Science:

• Tribology
• Materials Science
• Nanotechnology

Background:

• Friction reduction is crucial for nanotechnology.
• Current methods focus on atomic configuration and motion.
• Modulating interfacial electronic properties for friction reduction remains unclear.

Purpose of the Study:

• To explore friction and wear reduction by modulating interfacial electronic properties.
• To investigate the effect of alternating electric current on friction.
• To develop an electronic-level friction model.

Main Methods:

• Applying 1 kHz alternating electric current to conductive Ir AFM tip and graphene on Ni substrate.
• Measuring friction force and wear over time.
• Developing and utilizing the PTT-E model for electronic-level friction analysis.

Main Results:

• Friction force reduced to 1/4 of its original value.
• Sustained friction reduction for over 70,000 seconds under high contact pressure (9.1 GPa).
• No obvious wear observed during the experiment.
• PTT-E model confirmed dynamic electron density redistribution as the key factor.

Conclusions:

• Alternating electric current effectively reduces friction and wear by inducing dynamic electronic density redistribution.
• This strategy offers a feasible and robust method for nanomechanical devices.
• Advances the understanding of electronic contributions to friction tuning.