Industrial ceramics, that is, ceramics for industrial production and industrial products. It is a kind of fine ceramics, which can play mechanical, thermal, chemical and other functions in application. Because industrial ceramics have a series of advantages, such as high temperature resistance, corrosion resistance, wear resistance, erosion resistance, etc., they can replace metal materials and organic macromolecule materials for harsh working environment. They have become an indispensable and important material in traditional industrial transformation, emerging industries and high-tech industries. They are widely used in energy,aerospace, machinery, automobiles, electronics, chemical industry and other fields. Wide application prospects. Ceramics with good corrosion resistance and chemical stability in contact with biological enzymes are used to produce crucibles, heat exchangers and biomaterials such as dental artificial lacquer joints for smelting metals. Ceramics with unique neutron capture and absorption are used to produce various nuclear reactor structural materials. 

1.Calcium oxide ceramics

   Calcium oxide ceramics are ceramics mainly composed of calcium oxide.Properties: Calcium oxide has NaCl crystal structure with a density of 3.08-3.40g/cm and a melting point of 2570 C.It has thermodynamic stability and can be used at high temperature (2000 C). It has low reaction with high active metal melts and less pollution by oxygen or impurity elements. The product has good corrosion resistance to molten metal and to molten calcium phosphate. It can be formed by dry pressing or grouting.

Application:

1) It is an important container for smelting non-ferrous metals, such as high purity platinum and uranium.

2) Calcium oxide brick stabilized by titanium dioxide can be used as lining material for rotary kiln of molten phosphate ore.

3) In terms of thermodynamic stability, CaO exceeds SiO 2, MgO, Al2O 3 and ZrO 2, and is the highest in oxides. This property shows that it can be used as a crucible for melting metals and alloys.

4) In the process of metal melting, CaO samplers and protective tubes can be used, which are mostly used in the quality management or temperature control of active metal melts such as high titanium alloys.

5) In addition to the above, CaO ceramics are also suitable for insulation sleeves for arc melting or vessels for balancing 

experimental angles.

Calcium oxide has two disadvantages:

①It is easy to react with water or carbonate in the air.

②It can melt with oxides such as iron oxide at high temperature. This slagging action is the reason why ceramics are easy to corrode and have low strength. These shortcomings also make it difficult for calcium oxide ceramics to be widely used. As a ceramics, CaO is still in its infancy. It has two sides, sometimes stable and sometimes unstable. In the future, we can better plan its use and make it join the ranks of ceramics through the progress of raw materials, forming, firing and other technologies. 

2. Zircon ceramics

   Zircon ceramics are ceramics mainly composed of zircon (ZrSiO4).

   Properties: Zircon ceramics have good thermal shock resistance, acid resistance and chemical stability, but poor alkali resistance. The thermal expansion coefficient and thermal conductivity of zircon ceramics are low, and their bending strength can be maintained at 1200-1400 C without decreasing, but their mechanical properties are poor. The production process is similar to that of general special ceramics.

   Application:

1) As an acid refractory, zircon has been widely used in low alkali aluminoborosilicate glass kilns for glass ball and glass fiber production. Zircon ceramics have high dielectric and mechanical properties, and can also be used as electrical insulators and spark plugs.

2) Mainly used for making high-strength high-temperature electric ceramics, ceramic boats, crucibles, high-temperature kiln burning plate, glass furnace lining, infrared radiation ceramics, etc.

3) Can be made into thin-walled products - crucible, thermocouple sleeve, nozzle, thick-walled products - mortar, etc.

4) The results show that zircon has chemical stability, mechanical stability, thermal stability and radiation stability. It has good tolerance to actinides such as U, Pu, Am, Np, Nd and Pa. It is an ideal medium material for solidifyinghigh-level radioactive waste (HLW) in steel system.

   At present, the research on the relationship between the production process and mechanical properties of zircon ceramics has not been reported, which hinders the further study of its properties to a certain extent and limits the application of zircon ceramics.

3. Lithium oxide ceramics

   Lithium oxide ceramics are ceramics whose main components are Li2O, Al2O3 and SiO2. The main mineral materials containing Li2O in nature are spodumene, lithium-permeable feldspar,lithium-phosphorite, lithium mica and nepheline.

   Properties: The main crystalline phases oflithium oxide ceramics are nepheline and spodumene, which are characterized by low thermal expansion coefficient and good thermal shock resistance.Li2O is a kind of oxide outside the network, which can strengthen the glass network and effectively improve the chemical stability of glass.

   Application: It can be used to make lining bricks, thermocouple protection tubes, constant temperature parts, laboratory utensils, cooking utensils, etc. of electric furnaces (especially induction furnaces). Li2O-A12O3-SiO 2 (LAS) series materials are typical low expansion ceramics, which can be used as thermal shock resistant materials, Li2O can also be used as ceramic binder, and have potential application value in glass industry.

4. Ceria ceramics

Cerium oxide ceramics are ceramics with cerium oxide as the main component.

   Properties: The product has a specific gravity of 7.73 and a melting point of 2600 ℃.It will become Ce2O3 in reducing atmosphere, and the melting point will be reduced from 2600 ℃ to 1690℃ . The resistivity is 2 x 10 ohm cm at 700 ℃ and 20 ohm cm at 1200 ℃. At present, there are several common process technologies for industrial production of cerium oxide in China as follows:Chemical oxidation, including air oxidation and potassium permanganate oxidation;Roasting oxidation method

Extraction separation method

   Application:

1)It can be used as heating element, crucible for smelting metal and semiconductor, thermocouple sleeve, etc.

2)It can be used as sintering aids for silicon nitride ceramics, as well as modified aluminium titanate composite ceramics, and CeO 2 is an ideal toughening 

stabilizer.

3) Rare earth tricolor phosphor with 99.99% CeO 2 is a kind of luminous material for energy-saving lamp, which has high light efficiency, good color rendering and long life.

4) CeO 2 polishing powder with a mass fraction greater than 99% has high hardness, small and uniform particle size and angular crystal, which is suitable for high-speed polishing of glass.

5) Using 98% CeO 2 as decolorizer and clarifier can improve the quality and properties of glass and make it more practical.

6) Ceria ceramics have poor thermal stability and strong sensitivity to atmosphere, which limits its use to a certain extent.

5. Thorium oxide ceramics

   Thorium oxide ceramics refer to the ceramics with ThO2 as the main component.

   Properties: pure thorium oxide is cubic crystal system, fluorite-type structure, the thermal expansion coefficient of thorium oxide ceramics is larger, 9.2*10/℃ at 25-1000 ℃, the thermal conductivity is lower, 0.105 J/(cm.s ℃at 100 ℃, the thermal stability is poor, but the melting temperature is high, the high temperature conductivity is good, and there is radioactivity. Grouting (10% PVA solution as suspension agent) or pressing (20% thorium tetrachloride as binder) can be used in the forming process.

   Application: Mainly used as crucible for smelting osmium, pure rhodium and refining radium, as heating element, as searchlight source, incandescent lamp shade, or as nuclear fuel, as cathode of electronic tube, electrode for arc melting, etc. 

6. Alumina Ceramics

   According to the difference of main crystalline phase in ceramic billet, it can be divided into corundum porcelain, corundum-mullite porcelain and mullite porcelain. It can also be divided into 75, 95 and 99 ceramics according to the mass fraction of AL2O3.

   Application:

   Alumina ceramics have high melting point, high hardness, high strength, good chemical corrosion resistance and dielectric properties. However, it has high brittleness, poor impact resistance and thermal shock resistance, and can not withstand drastic changes in ambient temperature. It can be used to manufacture high temperature furnace tubes, linings, spark plugs of internal combustion engines, cutting tools with high hardness, and thermocouple insulating sleeves. 

7. Silicon carbide ceramics

   Silicon carbide ceramics are characterized by high temperature strength, high thermal conductivity, high wear resistance, corrosion resistance and creep resistance. They are often used as high temperature sintering materials in the fields of national defense and Aerospace Science and technology. They are used to manufacture high temperature parts such as nozzles for rocket nozzles,throats for casting metal, thermocouple bushings and furnace tubes.