Earth Science: The Work of Chemists – Materials of Tomorrow
Tomorrow’s materials will be lighter, more stable, more heatproof, and more “intelligent.” New nanomaterials with microscopic structures open up new options while improvements continue for steel and ceramics.
Steel contains iron and varying alloying elements. A alloying element or elements change the character of the steel. For example steel with a 15 percent manganese content enriched with a 3 percent aluminum and silicon content does not rupture, even at tensions as high as 1,100 megapascals.
That is the equivalent to the weight of ten bull elephants on an area the size of a postage stamp. Conventional steel can resist only 700 megapascals. Another type of steel can be stretched length- wise by around 90 percent without rupturing.
When this type of steel is used in cars, the behavior of the vehicles in a crash is much improved. Furthermore, this particular steel can reduce the weight of an auto body by around 20 percent, helping to improve gas mileage and performance. Steel of this type is difficult to produce but, in the future, most automobiles will benefit from its use.
Substances with memory
There has been an accident and a fender was dented, wouldn’t it be good if the dent could just disappear? That could be a reality if the fender were made of a shape
memory material. These advanced materials “remember” their original shape and return to it when heat is applied.
So the dent from the accident could be repaired by simply applying heat, a task that can be done at home without requiring a trip to an auto body shop.
Metals that remember shape
We already have plastics with shape memory. However, there are also metals with the same characteristic. A special nickel-titanium alloy allowed the European research satellite ENVISAT-1 to open its “eyes” after it reached its orbit in 2002. Shape memory metals are also used in medicine.
For example, wire nettings called stents are placed in coronary arteries that are constricted by disease. When exposed to the warmth of blood, the stents expand and support the arteries thereby improving blood flow.
Many physicians and other re-searchers are experimenting with additional materials and transplants to improve the lives of their patients, bringing the materials of tomorrow to the hospitals of today.
HIGH-PERFORMANCE CERAMICS
Modem high performance ceramics are very different from the fragile earthenware of ancient times Ceramics can be made break proof by adding carbon fibers. Fitted on the nose of a space shuttle, these reinforced ceramics protect the vehicle from the enormous heat produced during reentry into the atmosphere in the form of ceramic tiles.
A similar ceramic is used for rotor disks in brakes because of its ability to resist wear and corrosion.