Graphene balls improve oils lubricants performance
Scientists and researchers at Northwestern University try to solve the problem of wasted fuel in vehicles due to friction, because, for the average car, 15 percent of the fuel consumption is spent overcoming friction in the engine and transmission. When friction is high, gears have to work harder to move.
This means the car burns more fuel and emits more carbon dioxide into the atmosphere. Every year, millions of tons of fuel are wasted because of friction, of course that bad for the environment and economic also.
Researchers tested crumpled graphene balls as a lubricant additive. In a series of tests, oil modified with crumpled graphene balls outperformed some commercial lubricants by 15%, both in terms of reducing friction and the degree of wear on steel surfaces.
About five years ago discovered crumpled graphene balls are a novel type of ultrafine particles that resemble crumpled paper balls. The particles are made by drying tiny water droplets with graphene-based sheets inside. The scientists explain that capillary force generated by the evaporation of water crumples the sheets into miniaturized paper balls, just like how we might crumple a piece of paper with our hands.
Nanoparticles, particularly carbon nanoparticles, have been previously studied to help increase the lubrication of oil. The particles, however, usually do not disperse well in oil and instead tend to clump together, which makes them less effective for lubrication. The particles may jam between the gear’s surfaces causing severe aggregation that increases friction and wear. To overcome this problem, past researchers have modified the particles with extra chemicals, called surfactants, to make them disperse. But this still doesn’t entirely solve the problem as surfactant molecules can rub off and decompose, making the particles clump up again.
Their unique shape makes crumpled graphene balls self-disperse without needing surfactants, as their pointy surfaces render them unable to make close contact with other graphene balls. Even when they are squeezed together, they easily separate again when disturbed.
With their pointy surfaces, they are unable to make close contact with the other graphene balls. Even when they are squeezed together, they easily separate again when disturbed. researchers team also found that performance of crumpled graphene balls is not sensitive to their concentrations in the oil. A few are already sufficient, and if you increase the concentration by 10 times, performance is about the same, So for all other carbon additives, such performance is very sensitive to concentration, and research work to find the sweet spot.
The problem with finding a sweet spot is that, during operation, the local concentration of particles near the surfaces under lubrication could fluctuate. This leads to unstable performance for most other additive particles.” Next, the team plans to explore the additional benefit of using crumpled graphene balls in oil: they can also be used as carriers. Because the ball-like particles have high surface area and open spaces, they are good carriers for materials with other functions, such as corrosion inhibition. Explore further: Researchers Discover New Properties of World’s Thinnest Material More information: Self-dispersed crumpled graphene balls in oil for friction and wear reduction.