Unveiling the Potential of Superlubricity in Load-Bearing Systems
By Strategic Research Institute on Jun 13, 2023 08:00 am
Scientists at Oak Ridge National Laboratory have made a remarkable breakthrough in the field of tribology, introducing an innovative coating that holds the promise of revolutionizing load-bearing systems. By utilizing carbon nanotubes, this groundbreaking coating has the potential to drastically reduce friction in common systems with moving parts, ranging from vehicle drive trains to wind and hydroelectric turbines. The researchers envision a future where the coating's ability to minimize friction and wear could lead to significant energy savings, amounting to a staggering $1 trillion annually in the United States alone.
Jun Qu, the leader of ORNL's Surface Engineering and Tribology group, explains that friction and wear occur when components slide past each other. By reducing friction, energy consumption can be decreased, while minimizing wear can enhance the durability and reliability of the system. In their study, recently published in Materials Today Nano, Qu and his team focused on a coating composed of carbon nanotubes, which imbued sliding parts with the remarkable property of superlubricity. Superlubricity is characterized by an extremely low coefficient of friction, often below 0.01, compared to approximately 0.5 for dry metals and around 0.1 when lubricated with oil.
The process involved growing carbon nanotubes on steel plates, which then formed a coating on the surface. These vertically aligned carbon nanotubes, resembling blades of grass, play a crucial role in reducing friction. As the steel parts slide against each other, the nanotubes act like tiny blades, cutting through the grass-like structure and generating fractured nanotube debris. This debris is subsequently deposited onto the contact surface, forming a graphene-rich tribofilm that dramatically reduces friction. The carbon nanotubes demonstrate their effectiveness in achieving superlubricity, with coefficients of friction as low as 0.001.
However, the presence of oil is crucial for the coating's superlubricity to manifest. Without oil, the aggressive nature of friction removes the carbon nanotubes, preventing the formation of the tribofilm. The coating's superlubricity remains stable even after more than 500,000 rubbing cycles, demonstrating its durability and long-lasting performance.
This significant breakthrough in tribology showcases the power of collaboration and advanced material characterization technologies. The multidisciplinary nature of tribology necessitates experts in various fields, such as carbon nanotubes, tribology, and materials characterization, working together to achieve success. Oak Ridge National Laboratory has been at the forefront of tribology research, with their previous work in ionic anti-wear additives receiving recognition and industrial partnerships.
Looking ahead, the researchers hope to further develop this technology through collaborations with industry partners. Their goal is to test, refine, and license the superlubricity coating, envisioning its integration into high-performance vehicles and power plants in the coming decade. By minimizing energy losses due to friction and wear, this pioneering coating could drive significant advancements in energy efficiency across diverse sectors.