Jun 09, 2020 | |
Nanodiamonds slip n' slide(Nanowerk News) Scientists tested the performance of a dry, oil-free lubricant that could improve efficiency and decrease waste in industrial machinery. The dry solid lubricant includes diamond nanoparticles (Applied Physics Letters, "Superlubricity in rolling/sliding contacts"). It creates a surface coating that reduces friction 20-fold compared to oil-based lubricants. |
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Bearings and gears are critical components in machines such as wind turbines and automobile engines and transmissions. These machines often require oil-based lubricants. These lubricants must be replaced when they break down. This reduces overall productivity and generates hazardous waste. Dry, oil-free lubricant alternatives can help improve energy efficiency by working better than oil-based lubricants. They can also reduce the adverse environmental effects of replacing lubricants. | |
Transmission electron microscopy depicts wear debris from tests with the solid lubricant consisting of (a) nanodiamonds, (b) amorphous carbon, and (c) molybdenum disulfide iwith nanodiamonds. (© AIP Publishing) | |
Due to high contact pressure and sliding velocity, bearings and gears often experience significant wear, such as the formation of micro-scale pits on the surface of the machinery. Traditionally, machinery uses oil-based lubricants to reduce wear. Oil-based lubricants are sometimes improved by using diamond-like carbon (DLC) coatings. | |
DLCs help to mitigate macro- and micro pitting in oil-lubricated contacts. This study went one step further by testing the potential of nanoscale solid lubricants along with DLC in a completely dry, oil-free environment for the first time. Nanoscale solid lubricants are made of tiny particles measuring just billionths of a meter. | |
For this study, the scientists designed a micro-pitting rig to test the performance of DLC, in combination with two-dimensional molybdenum-disulfide materials and nanodiamonds. The combined material is a potential oil-free lubricant in dry conditions. | |
The scientists also used facilities at the Center for Nanoscale Materials, a Department of Energy Office of Science user facility, to conduct Raman microscopy, scanning electron microscopy/energy dispersive X-Ray spectroscopy, and transmission electron microscopy characterization of the lubricants and surface wear in the experiment. | |
The experiment demonstrated that under dry conditions, the solid lubricant achieved superlubricity (near-zero friction) by creating a carbon-rich layer between sliding surfaces. The lubricant reduced traction by about 13 times compared to a previous oil-lubricated micro-pitting rig test. Additionally, compared to steel-on-steel contacts lubricated with oil, the dry lubricants reduced traction by at least 20 times. | |
These results indicate the new solid lubricant could dramatically reduce wear and improve the efficiency of machinery. |
Source: U.S. Department of Energy, Office of Science | |
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