Oil changes are part of the routine maintenance for most drivers to keep their cars in good running condition. Engine oil reduces the friction between moving parts of the engine and minimize its wear and tear. Like cars, a variety of machinery—whether a printing press or an excavator—also relies on lubricants to prevent breakdowns and maximize productivity.
Christina P. Twist and her colleagues at Northwestern University in Illinois, USA have developed a new lubricant by combining nanometer-sized silver particles with engine oil.
Lubrication is critical to improving the energy efficiency and performance of machinery parts such as bearings and gears. Two types of lubrications are generally used: oils and greases, and solid lubricants such as coatings or particles dispersed in oil. Conventional oils and greases suffer from severe degradation when used at high temperatures (~250˚C). Recently, solid lubricants containing nanometer-sized particles of zinc or titanium dioxide have been used because they are more stable in oils than larger particles.
The ability of nanoparticle additives to reduce wear and friction determines their suitability as lubricant additives. Silver is an ideal additive for solid lubricants because its softness and ductility allow surfaces to easily slide over each other—improving lubricity.
Using a silver-oil lubricant rather than a silver surface coating is a more efficient and cost-effective means of getting the silver particles where they are needed to reduce frictional contact.
Compared to engine oil alone, the addition of silver nanoparticles significantly reduced wear during pin-on-disk friction tests. Researchers found it to enhance the wear resistance by as much as 79% in some cases. Such a reduction in wear would mean a substantial improvement in a machine’s operating lifetime.
We usually associate silver nanoparticles with their antimicrobial properties and don’t often hear about their other properties. So I wanted to share some research that shows silver nanoparticles are ideal for other applications as well.
Twist, C., Seyam, A., Chen, C., Kim, M., Weberski, M., Ren, N., Marks, T., Chung, Y., & Wang, Q. (2012). Molecularly-Engineered Lubricants: Synthesis, Activation, and Tribological Characterization of Silver Complexes as Lubricant Additives Advanced Engineering Materials, 14 (1-2), 101-105 DOI: 10.1002/adem.201100193