Science News Archive

Super slippery material

If you are making a machine with moving parts you often want to make parts slide past each other efficiently. Normally this is achieved by covering the parts with oil or another lubricant which can significantly reduce the friction but this isn't that effective, and the lubricant can escape. There are also a variety of low friction coatings such as Teflon, which you can find on non-stick frying pans, and have been used to slide whole motorway slip roads around. However these are very soft and wouldn't last five minutes on a gear wheel.

Scientists from the Ames Laboratory in the US may have accidently discovered a material which could solve this problem. They were searching for a material to generate power when you heat one side, and one of the materials they tried was Aluminium Magnesium Boride (AlMgB₁₄) this didn't work for what they were testing it on, and it was extreemly difficult to cut and polish. Instead of being frustrated by this they investigated more closely and tried mixing it with titanium boride and found that it was extreemly hard, the third hardest material found so far after diamond and Carbon Boron Nitride, so it should be hard wearing. They also looked into how slippery it is and it seems to have a coefficient of friction of 0.02 that means that if you pushed down with 100N you would only have to push with 2N to be able to slide. In comparison teflon is more than twice as sticky so you would have to push with 5N and lubricated steel is 8 times stickier.

At the moment the material is expensive and difficult to produce, but if you just applied the coating to all the pump blades in the US the reduction in friction would save over 100 million pounds a year in reduced energy costs.

23rd Nov 2008