Main raw material of alumina ceramics - special alumina

Special alumina is a kind of alumina powder with a particle size of sub-micron. The size of the powder is between 1-100 um, it is white powder, and the crystal phase is α-Al2O3. It has high temperature resistance and inertia. High strength, high toughness, corrosion resistance, wear resistance, high insulation, and high chemical stability, and it is the hardest substance in the world after diamond (for example, diamond is a known very hard substance, and its Mohs hardness is 10, and the Mohs hardness of alumina is 9). During the production process, it grows uniformly in three-dimensional space through structural regulation, showing microcrystalline spherical shape and good dimensional stability. Zhongchao Co., Ltd. modified its surface during the production process, showing many unique and excellent properties, such as high purity, concentrated particle size distribution, good dispersibility, uniform powder original crystal, and high crystallinity. It can be widely used in the reinforcement and toughening of various plastics, coatings, rubber, ceramics, refractories and other products.

Alumina ceramics are based on the excellent characteristics of special alumina, with high melting point, high hardness, chemical corrosion resistance, and excellent dielectric properties. It is a stable crystal form in various forms of alumina, and it is also the only crystal form of alumina that exists in nature. Its functions in ceramics are mainly: wear resistance, increased strength, and formation of surface composite coatings. This coating improves the mechanical, physical and chemical properties of the substrate surface and endows the substrate surface with new mechanical, thermal, optical, electromagnetism and catalytic sensitivities. Achieve the purpose of material surface modification and functionalization.

Special alumina materials have special optoelectronic properties, high magnetoresistance, nonlinear resistance, high strength, high toughness, good stability and other exotic properties at high temperatures, as well as the small size effect shared by various nano-powder materials., surface interface effect, quantum size effect and macroscopic quantum tunneling effect, so alumina ceramics can be used to manufacture high-speed cutting tools, high-temperature thermoelectric coupling sleeves, chemical high-pressure mechanical pump parts, internal combustion engine spark plugs, artificial joints and aviation magnetohydrodynamic power generation materials and other ceramic devices. It has broad application prospects in the fields of catalysis, light filtering, light absorption, medicine, magnetic media and new materials.

Ceramic Properties of Special Alumina Sintering

► High mechanical strength

The flexural strength of Al2O3 porcelain sintered products can reach 250MPa, and the hot-pressed products can reach 500MPa. The purer the Al2O3 composition, the higher the strength. The strength can be maintained to 900 ° C at high temperature. Using its mechanical strength, device porcelain and other mechanical components can be made. The strength of ceramics sintered with special alumina is improved, and it is not easy to break.

► High resistivity, good electrical insulation performance

The resistivity at room temperature is 1015Ω · cm, and the insulation strength is 15kV/mm. Using its insulation and strength, it can be made into substrates, tube seats, spark plugs, circuit shells, etc.

► High hardness

With a Mohs hardness of 9 and excellent wear resistance, it can be used to manufacture grinding wheels, abrasives, wire drawing dies, extrusion dies, bearings, etc.

► High melting point, corrosion resistance

The melting point is 2050 ℃, which can better resist the erosion of molten metals such as Be, Sr, Ni, Al, V, Ta, Mn, Fe, Co. It also has high resistance to the erosion of NaOH, glass and slag. Therefore, it can be used as refractory materials, furnace tubes, glass brushed crucibles, hollow spheres, thermocouple protective sleeves, etc.

► Excellent chemical stability

Many complex sulfides, phosphide compounds, chlorides, oxides, etc., as well as sulfuric acid, hydrochloric acid, nitric acid, and hydrofluoric acid do not interact with Al2O3. Therefore, Al2O3 can be made into crucibles, human joints, artificial bones, hydroxyapatite-coated polycrystalline alumina ceramic artificial teeth, etc.

► Optical properties

Light-transmitting materials (light-transmitting Al2O3 porcelain) can be made to manufacture sodium vapor lamps, microwave fairings, infrared windows, laser oscillating elements, and the like.

► Ionic conductivity

Used as solar cell material and battery material.

With the continuous advancement of nano-science and technology, it has had a profound impact on the application of the alumina industry. As a special functional material, special alumina has high hardness, high strength, corrosion resistance, wear resistance, high temperature resistance, high insulation, High oxidation resistance and many other excellent characteristics, so it is widely used in precision ceramics, bioceramics, chemical catalysts, refractory materials, integrated circuits and aerospace.