Because of its excellent high-temperature properties and mechanical strength, corundum is widely used in many industrial fields such as metallurgy, machinery, chemical industry, electronics, aviation and national defense. Its main uses are as follows.
1. Because of its high temperature resistance, corrosion resistance and high strength, it is used as a sliding nozzle for pouring steel, smelting rare precious metals, special alloys, high-purity metals, glass drawing, making laser glass crucibles and utensils; various high-temperature furnaces , Such as refractory materials, ceramics, iron-making blast furnace lining (wall and pipe); physical and chemical utensils, spark plugs, heat-resistant and oxidation-resistant coatings. Low-silicon sintered corundum bricks with SiO2 less than 0.5% are special linings for carbon black, boron chemicals, fertilizers, synthetic ammonia reactors and vaporization furnaces.
2. Due to the characteristics of high hardness, good wear resistance and high strength, it is used as parts of various reaction vessels and pipelines and chemical pumps in chemical systems; as mechanical parts and various molds, such as wire drawing dies, extrusion Pencil core mold nozzles, etc.; used as knives, abrasives, bulletproof materials, human joints, sealing grinding rings, etc.
3. Because of the high temperature insulation, it is used as the wire tube and protection tube of the thermocouple. The insulation used in the atomic reactor is still excellent. In addition, the loss is not large, the dielectric constant is not large, and it is widely used in the electronics industry. Used for solid integrated electric furnace base plate tube base, shell, porcelain frame, thin window, missile radar antenna protective cover, etc.
4. Al2O3 is an ionic crystal with a very stable structure. Used under high frequency, high pressure and higher temperature, its insulation is still excellent, and the loss is not large, and the dielectric constant is not large. It is widely used in the electronics industry to extrude solids into circuit substrate sockets, shells, and porcelain. Frame, micro glass window, missile radar antenna protective cover, etc.
5. Corundum products have good airtightness and are tight and airtight even at high temperatures. Therefore, they are widely used in electric vacuum. For example, corundum is used to make various large electronic tube shells and dual-in-line packaging shells in solid microcircuits.
6. Corundum insulation materials, such as corundum lightweight bricks, corundum hollow balls and fiber products, are widely used in the walls and roofs of various high-temperature furnaces, which are both high-temperature resistant and thermally insulated.
7. Transparent corundum products can be used to make tubes and microwave fairings. In addition, Na-b-Al2O3 products are electrolyte materials for the manufacture of sodium-sulfur batteries.