Breakthrough Solid Lubricant Prevents Friction at High Temperatures

In a joint collaboration of several universities, researchers at Virginia Tech have discovered a new solid lubricating strategy that significantly reduces friction in machinery at extremely high temperatures. It performs well beyond the breakdown temperature of traditional options such as graphite. The findings were published in Nature Communications.

Rebecca Cai, associate professor in the Department of Materials  Science and Engineering and one of the authors of the study, said that this breakthrough solid-state lubricant could make high-tech engines last longer and work better under extreme conditions that only now about 20 solid lubricants have been identified after decades of research.

Choosing the right lubricant could extend a jet engine’s life, saving millions of dollars, but most of those roughly 20 identified lubricants break down when machinery reaches temperatures as extreme as molten lava. 

It’s estimated that friction and wear cost the U.S. economy over $1 trillion in 2023, equivalent to about 5 percent of the gross national product, showing how important this discovery is.

In various industrial applications like advanced manufacturing, transportation, and aerospace, too much friction causes machines to wear down. 

In these cases, lubricants or substances are used to reduce friction between two surfaces that come into contact with each other. Although these solutions are key to safe operating conditions and optimal performance, developing materials that resist wear above 600 degrees Celsius (1,000 degrees Fahrenheit) remains a challenge. 

To achieve this, it required extensive collaboration among experts at multiple institutions.

The discovery also depended on a device called a high-temperature tribometer, which Cai added to her lab in 2019, to quantify friction and wear at conditions surpassing the capabilities of conventional equipment. Virginia Tech was a pioneer in housing this technology, allowing experiments at temperature extremes beyond previous limits.

By combining advanced materials analysis, computational models, and high-temperature testing, the researchers demonstrated that spinel oxide layers can naturally form on additively manufactured metal surfaces during high-temperature oxidation, allowing self-lubrication.

This happens because of the spinel oxide’s low shear strength, allowing their molecules to slip easily under stress, and maintain exceptional stability under those stressful and high-temperature conditions. After a range of computer simulations, they determined the best oxide candidates.

These findings position Virginia Tech as a leader in innovative technologies and cutting-edge research, offering new prospects for interdisciplinary problem-solving.

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