Detailed explanation of alumina ceramics, long knowledge


Advantages of alumina ceramics

(1) High mechanical strength, the bending strength of alumina ceramic sintered products can reach 250MPa, hot-pressed products can reach 500MPa, and the strength can be maintained at high temperature up to 900°C

(2) High resistivity, good electrical insulation performance, room temperature resistivity 1015 Ωcm, dielectric strength 15 kV/mm

(3) High hardness, Mohs hardness 9

(4) High melting point, anti-corrosion, melting point 2050℃, can better resist corrosion of molten metals such as Be, Sr, Ni, Al, V, Ta, Mn, Fe, Co, etc. It also has high corrosion resistance of NaOH, glass and slag. Does not interact with Si, P, Sb, Bi in an inert atmosphere.

(5) Excellent chemical stability, many compounds of sulfides, phosphides, arsenides, chlorides, nitrides, bromides, iodides, oxides and sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid are not oxidized Aluminum effect.

(6) Optical properties, the possibility of manufacturing light-transmitting materials (transparent porcelain Al2O3)

(7) Ionic conductivity

Disadvantages of alumina ceramics

Alumina ceramics have low impact strength, poor heat resistance and cannot withstand sudden temperature changes. The impact resistance is low, it breaks easily and cannot withstand high pressure. At the same time, due to its low brittleness, its post-processing ability is very weak, which does not promote recycling, and basically can only be used once.

Fields of application of alumina ceramics
  1. Mechanical aspects. With the characteristics of high hardness, strong mechanical properties at high temperatures, good wear resistance, good chemical stability and uneasy bonding with metals, alumina ceramic tools are widely used in cutting hard materials, cutting high speed steel, ultra-high speed cutting, etc. Cutting materials.
  2. Industry. At present, there are many kinds of industrial valves, and the most commonly used industrial valves are plug valves, gate valves, gate valves, ball valves, etc.
  3. Electronics, electricity. There are various alumina bottom plates, substrates, ceramic membranes, transparent ceramics and various alumina electrical insulating porcelain parts, electronic materials, magnetic materials, etc. Among them, the most widely used are transparent ceramics and alumina substrates.
  4. Chemicals. Alumina ceramics are also widely used in chemical applications, such as alumina ceramic chemical fillers, inorganic microfiltration membranes, anti-corrosion coatings, etc. Among them, alumina ceramic membranes and coatings are the most studied and applied.
  5. Medical aspects. Alumina is more used in the manufacture of artificial bones, artificial joints, artificial teeth, etc. Alumina ceramic has excellent biocompatibility, biological inertness, physical and chemical stability, high hardness and wear resistance, and is an ideal material for making artificial bones and artificial joints.
  6. In terms of architectural sanitary ware, alumina ceramic products can be seen everywhere, such as alumina ceramic facing bricks, grinding bodies, rods, ceramic protective tubes, and alumina refractory materials. Among them, alumina ball mills are the most widely used. Alumina ball mill has the characteristics of suitable hardness, moderate density, wear resistance, corrosion resistance and low price, so most of the building sanitary ware raw materials are processed by alumina ball mill.
  7. Other aspects. Alumina ceramics is currently one of the most studied and widely used materials in new materials..In addition to the above applications, it is also widely used in other high-tech fields such as aerospace, high-temperature industrial furnaces and composite reinforcement. .
Market prospects for alumina ceramics

Alumina ceramic is widely used in the field of lithium battery diaphragm coating and catalyst carrier because of its excellent physical and chemical properties.

  (1) High demand for high purity ultrafine alumina in downstream processing

The main function of the lithium-ion battery separator is to separate the positive and negative electrodes of the battery to prevent short circuit, and its performance directly affects the capacity and safety of the battery. During battery use, if the temperature is too high, the diaphragm will melt and cause a short circuit. Diaphragm coating can improve the temperature resistance of the battery. Ultra-fine high purity alumina has good insulation and high temperature. It is a high-quality diaphragm coating material.

(2)Environmental issues are becoming more and more prominent, and the automotive catalyst market is huge

Automotive exhaust catalyst carrier is honeycomb cordierite ceramic, the surface is coated with aluminum oxide and alumina coating alloyed with rare earth elements. Because vehicle exhaust contains toxic carbon monoxide, nitrogen oxides, and hydrocarbons, gasoline-powered vehicles are typically equipped with vehicle exhaust aftertreatment devices. Alumina ceramic is widely used in the field of catalyst supports due to its excellent physical and chemical properties. With the advent of the new energy industry, especially new vehicles, cermet materials will inevitably make a big splash in the field of new energy due to their excellent physical and chemical properties.