Modern alumina ceramic is among the hardest and strongest of advanced ceramic materials, offering strength, hardness, corrosion resistance and thermal stability at both room temperatures and elevated temperatures. There is an assortment of purity levels available.
Alumina ceramic requires high purity and low void content to produce superior mechanical properties and green body density. Therefore, optimizing processing parameters like spray granulation and particle size distribution to achieve these characteristics.
It has high hardness
Alumina ceramics are among the hardest and most abrasion resistant of advanced materials, outshone only by silicon carbide, boron carbide and diamond in terms of mechanical strength and compression strength (up to 250,000 PSI). Furthermore, their thermal conductivity is highly efficient while they also resist oxidation.
These properties make alumina ceramics highly desirable materials for many different applications, from abrasion resistance and corrosion/wear resistance, to heat-resistance and even surface hardening of metals. Alumina ceramics also make excellent high performance insulators and high frequency transmission devices.
To produce alumina ceramics, the process starts with extracting alumina from an alumina hydrate, which is then washed and dried to remove impurities. Next comes use by either a spray dryer or an aqueous slip as feedstock for ceramic dough feedstock sintering in molds; during which particle rearrangement, grain growth, pore elimination and up to 25% shrinkage may take place during heating processes.
After firing, the powder is finely ground to sub-micron levels to achieve the ideal after-firing grain size, which eliminates large voids. This ensures that the ceramic is capable of withstanding various stresses and strains associated with various applications including orthopedic use.
It has good wear resistance
Alumina ceramic has exceptional wear resistance, making it a highly valuable material in industry. Additionally, its hard, corrosion-resistant and chemical-resistant qualities make it suitable for many industrial furnaces and equipment; especially large-diameter flue systems with dust removal pipelines and large dust removal pipelines. Furthermore, this ceramic material can also be used for lining steel tubes conveying coal or cement storage facilities or cement hoppers etc.
The wear rate of alumina ceramics depends on several factors, including grain size, surface energy and microstructure. Studies have demonstrated that wear rate decreases with increasing grain size. Furthermore, their tribological behavior differs significantly depending on their granular structure and composition.
Rare-earth elements significantly improve the tribological behavior of crystalline alumina by filling surface defects and reducing grain energy, while slowing diffusion at grain boundary regions. This improves both wear resistance and performance of granular structure over time.
Toughened alumina is one of the ideal materials for industrial valves, as its superior performance under impact-abrasion and solid particle erosion wear regimes makes it stand out. Toughening methods include Zr02 phase transformation toughening, whisker toughening and second phase particle dispersion toughening; its impurity content plays a pivotal role in improving wear resistance.
It has good electrical properties
Alumina ceramics are electrically insulating, meaning that they prevent electricity from passing through them and reducing energy loss in electrical applications. Furthermore, alumina ceramics possess high dielectric strength — meaning they can withstand strong electric field strengths without breaking down and becoming ineffective as insulation in electrical devices — making it perfect for use as high voltage electrical insulators and environmental protection measures. Finally, their durable composition also makes alumina ceramics highly reliable insulators materials which do not break down easily over time.
Alumina can also be found in medical applications, including artificial joint surfaces. Alumina’s unique combination of properties — no porosity and high density; narrow grain size distribution; low concentration of sintering additives; etc — make it the ideal material for orthopedic applications.
Compare it with metals: Alumina ceramic boasts outstanding mechanical strength and resilience, resisting temperature fluctuations and chemical corrosion as well as being impervious to wear-and-tear conditions. Alumina’s resistance to both corrosive and abrasive media makes it suitable for pumps and valves while its thermal stability enables it to endure high temperatures.
Alumina ceramics can be machined post-sintering to form complex shapes. This process typically entails precision machining and various highly controlled sintering steps; during which particle rearrangement, grain growth, and pore elimination occur — key processes responsible for creating its high performance characteristics. Once complete, this product undergoes post-sintering procedures such as drilling, honing, and grinding before finally reaching completion.
It has good thermal conductivity
Alumina ceramics possess high melting temperatures and strength at both hot and cold temperatures, in addition to great thermal and electrical properties that make them suitable for various applications, such as pressure sensors, sputtering targets, electron tubes and laser components. Alumina ceramics can even be metallized, making them a popular choice for ceramic-to-metal and brazed assemblies as well as resisting corrosion and wear.
Alumina boasts excellent dielectric properties, withstanding high electromagnetic voltage without losing energy as electric current passes through it. This makes alumina ceramics available in an assortment of sizes, shapes, and materials the ideal material to act as insulators that prevent electrical current flow while at the same time blocking heat transference through them.
Injection molding is the go-to manufacturing method for alumina ceramics. This involves mixing granular alumina powder with binder into a viscous slurry that is then injected into molds to produce green parts. Once these have set, their binder can be removed before densifying through sintering.
Medical grade alumina ceramics should be free from porosity and feature fine, uniform microstructure with low concentration of sintering additives and narrow grain size distribution — ideal qualities for use as orthopedic prostheses articulating surfaces. In order to meet these criteria, manufacturing techniques must be employed that yield results like these — one such manufacturer is International Syalons in the UK which offers their comprehensive Aluminon brand line of ceramic products.
