New manufacturing method promises cheaper, greener ceramics
By Ben Coxworth
April 9, 2010
When you think of shaping ceramics, you probably think of a potter spinning a clay pot on a wheel, or perhaps even yourself making that piggy bank in art class. In reality, the term “ceramic” encompasses a lot more than fired clay, and shaping some of the more exotic forms can be quite involved. Researchers from North Carolina State University (NCSU), however, have recently discovered a new way of shaping ceramics. It should be much more energy-efficient than present methods, making the entire process more cost-effective and environmentally-friendly.
According to the Ceramic Tile Institute of America, a ceramic can be defined as any inorganic, non-metallic solid prepared by the action of heating and subsequent cooling. Besides your grandma’s china, ceramics can also include materials such as silicon carbide, tungsten carbide, and titanium carbide, just to name a few. They’re used in products such as insulators, spark plugs, fuel cells, body and vehicle armor, gas turbines, nuclear rods and heat shields.
There are a variety of methods of shaping these advanced ceramics, but generally they tend to involve heat... lots of heat. The team at NC State, however, have found a way of shaping them using an electrical current. Their process exploits a structural defect called a grain boundary, where crystals with atoms aligned in different directions meet within the ceramic material. These grain boundaries have electrical charges.
"If we apply an electric field to a material, it interacts with the charges at the grain boundaries and makes it easier for the crystals to slide against each other along these boundaries,” said NCSU’s Dr. Hans Conrad. “This makes it much easier to deform the material [...] We've found that you can bring the level of force needed to deform the ceramic material down to essentially zero, if a modest field is applied.” In some cases, he added, 25 to 200 volts per centimeter is all that’s required - the electricity from a conventional wall socket would suffice.
If this new process becomes commonplace, according to NCSU, manufacturers who make anything out of ceramics will be able to do so using less energy. This, in turn, should mean less expense and less pollution.