Characteristics of silicon carbide

Since silicon carbide chemical stability, high thermal conductivity, thermal expansion coefficient, good wear resistance, except for the abrasive used, there are many other uses, such as: a special process the silicon carbide powder coating on the turbine impeller or cylinder body wall, can improve the wear resistance and extend the life of 1 to 2 times; for advanced refractory material, heat shock, small size, light in weight high strength, good energy saving effect. A low-grade silicon carbide (containing about 85% SiC) is an excellent deoxidizer, with its speed steel to accelerate and facilitate control of the chemical composition, to improve the quality of steel. In addition, silicon carbide heating element is also used extensively for the production of silicon carbide.
Silicon carbide's hardness great, Mohs hardness of 9.5, second only to the world's most hard-diamond (10), with excellent thermal conductivity, is a semiconductor, resistant to oxidation at high temperatures.

ntroduction of silicon carbide?

Silicon carbide (SiC) with quartz sand, petroleum coke (or char), sawdust from electric arc furnace smelting. In nature there are also rare silicon carbide mineral moissanite. Silicon carbide, also known as Moissanite. In contemporary C, N, B and other non-oxide refractory materials in high-tech, silicon carbide is the most widely used and most economical one. Can be called emery or refractory sand. Silicon carbide is with quartz sand, petroleum coke (or coal tar), wood (green silicon carbide need to increase the production of salt) and other raw materials in high temperature resistance furnace smelting. At present China's industrial production of silicon carbide is divided into two kinds of black silicon carbide and green silicon carbide, are hexagonal crystals, accounting for 3.20 to 3.25, microhardness 2840 ~ 3320kg/mm2.

What material temperature

High temperature resistant material comprises a refractory material , an inorganic compound , there are polymer materials . More usually refers to the ability of the refractory 1580 ℃ temperature inorganic material. They are built furnaces , high temperature combustion and other needed supplies . Generally made ??of quartz sand , clay , magnesite, dolomite and other raw materials , high temperature thermal insulation coatings Chi Shing , is a component of the inorganic coating , the temperature in the range of -80-1800 ℃, thermal conductivity 0.03W/mK, can inhibit the body temperature and low-temperature heat radiation and conduction body heat , body temperature can be maintained for 70% of the heat is not lost . Chi Shing paint on surfaces coated 8mm 1100 ℃ high temperature insulation coating , the surface temperature can be reduced from 1100 ℃ to less than 100 ℃. In addition there is high temperature resistant insulation coating insulation , light weight, easy construction, long service life , high temperature resistant inorganic materials can also be used as acid crosslinking agent, attachments body firmly. Such as refractory cement , magnesia brick and so on. Broadly speaking , an inorganic fire- resistant material refers to those compounds with high hardness and brittleness , resistance to chemical corrosion , and the melting point of 1500. The main two types of intermetallic compounds with non-metallic and non-metallic compounds. The former such as tungsten , molybdenum , tantalum , niobium , vanadium , chromium , titanium, zirconium and rare earth metal refractory metal borides, carbides , nitrides , silicides, phosphides , and sulfides ; latter as boron carbide , silicon carbide , boron nitride , silicon nitride, boron phosphate , silicon phosphate and the like. The latter has a very important purpose , high temperature refractory material can be used (e.g., abrasives , molds, nozzles, high temperature thermowell ) , heat-resistant material ( such as structural components of the rocket, nuclear engineering materials , heating elements ) , electrical materials ( such as high temperature thermocouple, ignition electrode ) , also used as a chemical resistant material and a rigid material. Heat-resistant polymer film can be used as high temperature insulation materials, high temperature fiber , high temperature coatings, high temperature adhesives. According to the time of high temperature , high temperature materials is divided instantaneous temperature materials and a longer time . 1000 ~ 10000 ℃ former ability seconds to minutes . Ablative materials which are also high-temperature materials. For example, in 300 ~ 600 ℃, the air can maintain its mechanical strength, resistance to chemical corrosion.

The results of refractories

Acidic refractory silicon oxide as the main component , commonly used silica brick and clay . Silica brick containing 94% silica siliceous products, raw materials used are silica, silica brick scrap , with its strong acid slag corrosion resistance , high softening temperature under load , the volume does not shrink after repeated firing , even a slight expansion ; but its
vulnerability to erosion of basic slag , thermal shock resistanceis poor. Mainly used silica brick oven , glass melting furnaces , steel furnaces and other acidic thermal equipment . To fire clay brick as the main material containing 30% to 46 % alumina , is a weak acid refractory, thermal shock resistance, corrosion
resistance to acid slag has wide application .
Neutral alumina refractory oxide, chromium oxide or carbon as a main ingredient. Containing more than 95% of alumina corundum products is a wider use of high-quality refractory materials.
Chromium oxide as the main component of chromium slag bricks for good corrosion resistance , but poor thermal shock resistance , low temperature load deformation temperature . Carbon- carbon refractory bricks, graphite products and silicon carbide products, low coefficient of thermal expansion , high thermal conductivity , good thermal shock resistance , high temperature strength , resistance to acid and salt erosion, especially with a weak acid better resistance, metal and slag from wetting light . Widely used as a high-temperature furnace lining material , also used in petroleum, chemical autoclave liner.
Basic refractory magnesia , calcium oxide as the main component , is used magnesia brick . Magnesium containing more than 80 % to 85 % of the brickalkaline slag and iron slag has good resistance , high refractoriness than clay and silica brick . Mainly used for open-hearth , basic oxygen furnace , electric furnace, high temperature and non-ferrous metal smelting equipment and some equipment .

Refractory role

Refractories used in various fields of steel, nonferrous metals,glass, cement, ceramics, petrochemical, machinery, boilers, light,power, military and other national economy, industrial production is to ensure that these essential operational and technical development of basic materials, plays an irreplaceable role in the development of high-temperature industrial production.

Performance Refractories

White fused corundum is a high-grade refractory materials, color white, dazzling crystal, with a large volume density, low porosity, etc., can effectively improve the volume stability and thermal shock resistance of the material. White fused corundum is the main raw material for production of high uncertainty and shaped refractories for large ladle castable, high-grade iron trough castable, gunning mix, precast and monolithic refractories such as corundum bricks, corundum and mullite corundum quality cartridge body, refining a variety of corundum corundum plug porous brick, the overall composite nozzle spray gun and high temperature industrial furnace lining material and other products. Widely used in iron and steel, cement, ceramics, abrasives, petrochemical and other industries.

white aluminum oxide,black silicon carbide,green silicon carbide

In practical applications, such as requiring heat shock stability, structural spalling resistance, while resistance to slag erosion and high thermal conductivity properties, silicon carbide refractories should be preferred. From the development trend, silicon carbide monolithic refractories, not only in metallurgy, building materials industry has a pivotal position, with the introduction of large-scale circulating fluidized bed boiler and the transformation of a small power plant (gradually transformed into a clean burning heating boilers and garbage incinerator) silicon carbide monolithic refractories in the power sector will also be more widely applied. We would like to be able to develop their advanced performance, adapt to the development of amorphous silicon carbide refractories in various industries.