Advanced ceramics consist of metallic oxides, carbides, and nitrides that provide excellent hardness and resistance to high temperatures, wear, and corrosion. They are usually made by mixing powdered minerals with certain chemicals, followed by shaping and heating to form the part. They function as components in electronics, armor, cutting tools, jet engines, medical devices, heat exchangers, and many other products.
Most ceramic materials are metallic oxides, such as aluminum oxide and zirconium oxide. Aluminum oxide is called alumina, its mineral is called corundum, and as a gemstone it is known as sapphire or ruby, second only to diamond in hardness. Synthetic aluminum oxide is equally hard, and is very resistant to abrasion and wear. One of its primary applications is the transparent window for bar code readers in supermarkets.
Zirconium oxide combines strength and toughness with biocompatibility and high resistance to wear. These properties make it suitable for medical implants, particularly in the femoral head of hip implants, and in implants for knees, shoulders, and spines.
Some of the most important ceramics are metallic carbides, such as silicon carbide and tungsten carbide. Silicon carbide applications include heating elements for industrial furnaces, wear-resistant parts for pumps and rocket engines, and semiconductor substrates. Combining silicon carbide with boron carbide and other materials produces lightweight armor that protects people as well as airplanes and helicopters. Tungsten carbide provides superior hardness and strength, making it the material of choice for cutting tools.
Another group of ceramics is composed of nitrides, including silicon nitride and aluminum nitride. Silicon nitride’s excellent high temperature strength and fracture toughness make it ideal for aerospace applications such as bearings, bushings, and similar components. Aluminum nitride’s unusual combination of excellent thermal conductivity and high electrical resistivity make it uniquely valuable in semiconductor and other electronics applications.
Testing and Ceramics Characterization
Ceramics vary widely in chemistry, function, and shape, so at NSL our tests and characterization methods are tailored for each component.
Common advanced ceramics currently analyzed at NSL include:
- Alumina (Al2O3)
- Boron Carbide (B4C)
- Boron Nitride (BN)
- Chrome Oxide (Cr2O3)
- Magnesium Oxide (MgO)
- Silica (SiO2)
- Titanium Dioxide (TiO2)
- Zinc Oxide (ZnO)
- Zirconia (ZrO2)
- Mixtures (eg. Silica/alumina or silica/alumina/zirconia)
Examples of analyses include:
- Bulk Analysis (%): SiO2, Al2O3, ZrO2, CaO, K2O, Na2O, MgO, MnO, Fe2O3, P2O5, ZnO, Cr2O3, TiO2, HfO2
- Trace Analysis (ppm): Na, Mg, Al, Si, K, Ca, Ti, Fe, Zn, Se, Zr , Ag, Sn, Sb, Pb, Bi