Stainless steel has been around a hundred years and in fact was known in various isolated examples even before its apparent ‘invention’ in 1912. It has come a long way since its first uses, through the brushed finish of household goods in the Fifties and Sixties to high-tech kitchen design at the beginning of this century. And it can still be big news – the Samsung Galaxy S5 tablet comes in a choice of metal and plastic body and the smart money is that the metal in question will be – of course, stainless steel.
Why is stainless steel still so popular?
Stainless steel has the ‘stainless’ property because the top molecular level of any surface is a self-healing passivation layer which means that small scratches are not permanent and so it keeps its good looks and more importantly its non-corroded property for longer, even in some quite difficult conditions. There are special requirements for finishing seams, especially underwater, but as long as these areas are kept maintained, a stainless steel installation will last for years. Cleaning steel can be done in different ways and steel surface preparation would be done using abrasive blasting methods. A common example which everyone will be familiar with is the stainless steel tea sets often seen on TV on antique shows which look as good as new after decades of use with boiling water. Because stainless steel can be given different finishes – polished, matte and brushed – and still keep its easy care properties, it has kept its popularity for years and is still being widely used today. Its limitation is that it is really only useful for containers, industrial steel buildings, vehicles etc; it has no application in small circuits or other electronic devices.
Is there an alternative?
Stainless steel is so hardwearing that many designers of small electrical devices such as tablets and laptops don’t think further than the obvious, but there is a new material coming up fast on the outside which will, when manufacturing problems are ironed out, be a more than serious contender for stainless steel’s crown. Graphene, a new material developed at Manchester University in 2004 by Andre Geim and Kostya Novoselov, who went on to win Nobel Prizes for their work in this field. It had been known as a theoretical material for many years, in fact it was first considered as possible back in 1947, but its manufacture is so problematical that it is not currently a viable replacement for any material on the market at the moment. However, manufacture is now backed by an EU grant and the sheets of graphene which are being produced are larger and cheaper than they were even two years ago, so the outlook is bright.
So, what is graphene, exactly?
Graphene is a sheet of graphite molecules just one atom thick – this means that it is to all intents and purposes two-dimensional; it has width and height but no depth. It can be used in all kinds of applications, many still to be tested, but at the molecular level much testing is by computer model anyway, so research can go on with very little of the actual product to tinker with. It is expected that graphene will be able to replace metals and plastics and because it is so thin it is transparent, though not of course made of an intrinsically transparent material. It is immensely strong, will not wear out and unlike stainless steel does not ‘heal’ itself – it simply doesn’t get damaged in the first place. It is also useful potentially in batteries, electrical contacts and many other applications and it is entirely possible that one day there will be a mobile phone or tablet with almost every single component made from graphene, from the case to the screen to the actual working parts.
What else does it do?
The thing with graphene is that it isn’t totally understood yet, but there is little doubt that it will prove to have many uses. The bonds between the atoms is so strong and the ‘weave’ of them so dense that not even a helium atom can get through, helium being the smallest atom there is with just one electron. One application everyone is getting very excited about is in desalination plants, which are used all over the world in areas with low rainfall but could also be used at sea by container ships if they could be made small enough; graphene lends itself perfectly to miniaturisation. It goes without saying that it has a great future in the touch screen technologies, as it is flexible and almost unbelievably strong. Since most problems with screens come from cracks and other damage, this will be a huge step forward. In the medical field, it is used as a substrate for DNA recovery and this is useful potentially in gene research. In fact, the uses for graphene may well prove to be almost endless, and it won’t be long before we all wonder how we ever did without it.