"This breakthrough solid-state lubricant could change how we design materials for high-tech engines, making them last longer and work better under extreme conditions," said Rebecca Cai, associate professor in the Department of Materials Science and Engineering and one of the authors of the study. "After decades of research, only about 20 solid lubricants have been identified."
Choosing the right lubricant can extend a jet engine's life cycle, potentially saving millions of dollars, yet most of those roughly 20 identified lubricants degrade at temperatures as extreme as molten lava. The importance is immense, given that friction and wear were estimated to cost the U.S. economy more than $1 trillion in 2023, equating to nearly 5 percent of the nation's gross product.
Because materials science underpins advanced manufacturing and other emerging technologies, this discovery enhances Virginia Tech's reputation in forward-focused research, offering new prospects for interdisciplinary problem-solving.
Friction is essential for motion, but excessive friction in industries such as aerospace, transportation, and advanced manufacturing undermines machinery. Lubricants, substances that reduce surface contact wear, remain critical for reliable performance, yet engineering solutions that maintain their properties above 600 degrees Celsius (1,000 degrees Fahrenheit) are elusive. Achieving these results required extensive collaboration among experts at multiple institutions.
"Collaborative work with other universities brought many knowledgeable people together to share resources, which is crucial in this discipline," said then-Ph.D. student and first author Zhengyu Zhang. "The future of many industries will depend on advances in materials science, and such a wide topic requires varied expertise."
Key to this breakthrough was a high temperature tribometer, which Cai added to her lab in 2019. This sophisticated instrument quantifies friction and wear at conditions surpassing the capabilities of conventional equipment. Virginia Tech was an early adopter of this technology, enabling experiments at temperature extremes beyond previous limits.
By combining advanced materials analysis, computational models, and high-temperature testing, the team demonstrated that spinel oxide layers can naturally form on additively manufactured metal surfaces under elevated heat, allowing self-lubrication. This occurs because spinel oxides exhibit low shear strength, causing their molecules to slip easily under stress, and maintain exceptional stability under harsh conditions.
Initial computer simulations determined the best oxide candidates. Fine-tuning the surface of the metal induced the formation of these spinel oxides, which proved far more capable of withstanding high temperatures than earlier solid lubricants.
Each collaborating institution contributed distinct expertise:
- University of Florida used 4D transmission electron microscopy to pinpoint complex oxidized surface structures.
- Jackson State produced the initial additively manufactured metals.
- Arizona State helped secure funding and supported computational analysis.
- Iowa State conducted mechanical simulations to gauge oxide strength.
- Nebraska-Lincoln ran high-temperature hardness evaluations.
Virginia Tech coordinated the entire investigation, formulating the concept, executing high-temperature friction tests, conducting surface characterization, performing essential thermal and mechanical property calculations, and forecasting phase behavior for each oxide.
"This is a great achievement scientifically, and we are thankful to our collaborators who made it possible," Cai said. "Without Virginia Tech's resources and strong partnerships with fellow scientists at universities around the country, we would not have discovered this new family of solid lubricant. These findings highlight a promising approach to designing self-lubricating alloys for extreme temperatures."
Research Report:Spinel oxide enables high-temperature self-lubrication in superalloys
Related Links
Department of Materials Science and Engineering at VY
Space Technology News - Applications and Research
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
