Silicon carbide sic is composed of tetrahedra of carbon and silicon atoms with strong bonds in the crystal lattice. They also have higher hot strength compared to oxide bonded silicon carbide refractories. The durability of the experimental bricks was 34 times greater than that of chamotte bricks. Study on gelcasting of silicon nitridebonded silicon carbide. The growing steel industry is anticipated to drive the growth as the silicon carbide sic is used as a deoxidizing agent in the steel industry and is a major raw material in refractories production. They are capable of performing where other refractories cannot. Silicon nitride bonded silicon carbide snbsc refractories are the current stateoftheart sidewall materials. Vulcasil s silicon carbide refractories vulcan refractories. Pdf the kinetics and mechanisms of oxidation for a porous nitride bonded silicon carbide refractory material were investigated in air and carbon. Feb 15, 2002 silicon nitride bonded silicon carbide nbsc can be produced by heating a mixture of silicon and powder and silicon carbide grains and firing to temperature usually in the range 01450c in nitrogen. Applications of refractory carbides and nitrides are found extensively in machinery and equipment for protection against wear, erosion, and chemical attack. Cumirex and cumistar nitridebonded silicon carbide refractories have high thermal conductivity, superior thermal shock and oxidation resistance.
Kt refractories distributes silicon carbide bricks of the best quality at the most competitive prices worldwide. Sialon bonded silicon carbide refractories and ceramics can be formed in the same way, with addition of clay to the initial mixture. A method of fabricating a refractory brick based on silicone carbide sic is using 69% acid aluminum phosphate as binder. Over many years vulcan refractories full range of silicon carbide refractories have gained an international reputation for their quality and reliability.
Soluble in molten alkalis naoh, koh and molten iron. Silicon carbide is an important material in trisocoated fuel particles, the type of nuclear fuel found in high temperature gas cooled reactors such as the pebble bed reactor. They have a thermal conductivity ten times that of fireclay refractories, good corrosion and thermal shock. Silicon carbide bricks sic products are based on synthetically manufactured silicon carbide grains with selected bonding components and metal oxide additives tuned to the use. Vulcasil sn is a range of silicon nitride bonded silicon carbide materials designed to meet the most exacting conditions. Technical data item nsic brick nsic ball bulk density gcm3. Us2040236a process of making bonded silicon carbide. Publishers pdf, also known as version of record includes final page. Some of the physical and chemical properties of different types of refractories are given. Group sizes manufactured to customer specifications black silicon carbide grains for refractory applications. Over many years vulcan refractories full range of silicon carbide refractories have gained an. Nitridebonded silicon carbide refractories springerlink. It has the following features high thermal conductivity, high bending strength, good thermal shock resistance.
Optimum formulations for castables intended for different service conditions are proposed. Plastic refractories furnace walls are built using formwork by carefully air ramming each slice. Study on the aluminium phosphate bonded sic refractory. Silicon carbide refractory composition and products. Nitride bonded silicon carbide refractories cumirex. Degradation mechanisms and development of silicon carbide. Used in the manufacture of high temperature refractories, kiln furniture, bricks, platesetters and other special refractory shapes and crucibles.
Mar 06, 2001 the nitrogenbonded silicon carbide is produced by firing mixtures of highpurity silicon carbide and silicon, or a mineral additive in a nitrogen atmosphere, at high temperature usually 50. Hexoloy sintered alpha silicon carbide will outperform other commercially available ceramics or metal alloys, including superalloys. Recent developments in the understanding of the wear mechanisms of blast furnace refractories, and in laboratory testing methods, have been applied to the improvement of the resistance to alkali attack of silicon nitride. Refrax plusflow technical datasheet silicon carbide. Pdf specially treated graphite fortified alumina silicon carbide.
Vulcasil sn silicon nitride bonded silicon carbide vulcan. Silicon carbide bricks refractories are produced from silicon carbide, a raw material synthesized in a resistancetype electric furnace at temperature exceeding 2500c, through the reaction of silica with carbon. Development and properties of silicon carbide refractories. They have a thermal conductivity ten times that of. Refractory products plasticplastic gunning plasticgunning plastic gunning castablegunning castable castablecastable 4. Silicon carbide refractory castable plusflow technical datasheet refrax property sic value method typical chemical analysis 70,4 % din 51076 al 2 o 3 21,0 % sio 2 6,0 % fe 2 o 3 0,5 % cao 1,6 % others 0,5 % bulk density 2,67 gcm3 dinenv 14026 cold crushing strength dinenv 14026. The silicon carbide manufacturing process can be divided into two general steps. Hexoloy sa sic material hexoloy sa sic is a pressureless, sintered form of alpha silicon carbide, with a density greater than 98 percent theoretical. Zirconia is used when the material must withstand extremely high temperatures. Silicon carbide bricks silicon carbide bricks, silicon nitride bonded sic brick sic brick is made of high quality synthetically made silicon carbide grains sic and selected bonding components, including nitride, si3n4. There is a wide range of nonclay refractories, including basic, extrahigh alumina, silica, silicon carbide, and zircon materials. Silicon carbide refractories i nci nerators abstract silicon carbide refractories have unique properties for preventing slag and clinker adherence on the lower walls of incinerator furnaces. In this study, a different method has been followed to increase the thermo mechanical properties and oxidation resistance of al2o3sicc refractories.
Silicon carbide castable rongsheng refractory 4000f castable ceramics, coatings and putties cotronics christy refractories castable, precast shape, ceramic fiber low cement castables mt. Christy refractories offers several forms of silicon carbide bricks featuring excellent corrosion and thermal shock resistance. The most important bulk material is tungsten carbide sintered with a metallic binder that is usually cobalt. The chief causes of failure of refractories in boiler furnaces are slag adhesion, erosion, and failure of structure, dependent on the type of coals and feeds used. Proprietary, ceramics refractories sic based silicon. Silicon carbide appears as yellow to green to bluishblack, iridescent crystals. Silicon carbide brick is made of high quality sic and bonded by clay, nitride, si3n4.
Silicon carbide brick high thermal conductivity, high bending strength, good thermal shock resistance. Technical data item nsic brick nsic ball bulk density gcm3 2. It has a very fine grain structure 4 10 microns for excellent wear resistance and contains no free silicon, which makes it highly chemically resistant in both oxidizing and reducing. The development of bonded silicon carbide brick is mentioned. The global silicon carbide market size was valued at usd 2. The base of all silicon carbide sic refractories is refractory grade alpha silicon carbide, produced in large electrical resistance furnaces at approximately 2400c from a mixture of silicon, carbide, salt and sawdust. A mixture of pure silica sand and carbon in the form of finely ground coke is built up around a carbon conductor within.
This is mainly because of its high strength at elevated temperature, remarkable erosion and corrosion resistance, excellent thermal shock resistance and good oxidation. These refractory crystals are then classified, crushed and graded for use as grog or aggregate in bricks or shapes. Standard test method for evaluating oxidation resistance of. Siliconcarbide refractories article about siliconcarbide. A plastic refractory composition comprising, for each 100% by weight, about 50 to 90% silicon carbide grain having a sic content of at least 92% sic, 1 to 40% calcined or reactive alumina, 1 to 10% bentonite or ball clay, 0. It was established that silicon carbide scrap and spoilage material are suitable for the production of.
Expired lifetime application number us491781a inventor john p swentzel. The above typical values shown are based on average test result on standard samples. A layer of silicon carbide gives coated fuel particles structural support and is the main diffusion barrier to the release of fission products. The largest metals properties database available besides being is the most comprehensive metal properties database and knowledge source worldwide, with more than 10,000,000 property records for over 350,000 alloys, total materia gives you the highest quality and reliability of the only certified database of its kind in the industry. Over many years, vulcan refractories full range of silicon carbide refractories have gained an international reputation for their quality and reliability. Silicon carbide refractories in the lining of the cooler drum. The excellent characteristics of sic products, such as high thermal conductivity and high corrosion resistance against numerous process media make it particularly ideal. Al2o3sicc refractory batches fortified with various fractions of stg were prepared on a pilot plant scale, and their thermomechanical properties were studied. Vulcasil s silicon carbide refractories vulcasil s is a range of oxide, mullite and glass bonded silicon carbide materials designed to meet the most exacting conditions. Silicon carbide brick has the great features like high thermal conductivity and thermal shock resistance, low thermal expansion coefficient, high corrosion resistance, high. Hexoloy silicon carbide is one of the hardest highperformance materials available. Handbook of refractory carbides and nitrides sciencedirect. To fully utilize these properties, these refractories should be installed with arrangements for air cooling the rear surface. Request pdf silicon carbide refractory castables optimum formulations for castables intended for different service conditions are proposed.
Physicochemical characterisation of silicon carbide refractories. Savage silicon carbide plastic refractory rongsheng refractory silicon carbide, black silicon carbide changxing refractory silicon carbide castable products suppliers pdf study on the alumina silicon carbide. Physicochemical characterization of silicon carbide refractories. Silicon carbide and carbon graphite are two other refractory materials used in some very. The product of oxidation is amorphous silica or cristobalite, depending upon the temperature at which oxidation takes place. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed. Hexoloy aonarbides silic c high performance refractories. Refractories must be chosen according to the conditions they will face. The present study was undertaken to establish a methodology for character rising silicon carbidebased refractories, as detailed information is unavailable in the literature on this point. Properties are subjected to reasonable variation based on product shape etc. Silicon carbide nitride bonded brick data kt refractories. Us2752258a us491781a us49178155a us2752258a us 2752258 a us2752258 a us 2752258a us 491781 a us491781 a us 491781a us 49178155 a us49178155 a us 49178155a us 2752258 a us2752258 a us 2752258a authority us united states prior art keywords silicon silicon carbide silicon nitride bonded articles prior art date 19550302 legal status the legal status is an assumption and is not a legal conclusion. Pdf oxidation of silicon nitride bonded silicon carbide refractory.
Tests were carried out at the magnezit combine with silicon carbide refractories in the lining sections subjected to maximum wear in the 36mlong drum for the cooling of fired magnesite powder. High friction silicon carbide carbon composite sic product. Oxidation resistance is the ability of the silicon carbide sic in the refractory to resist conversion to silicon dioxide sio 2 and its attendant crystalline growth. Hexoloy silicon carbide is ideal for applications such as nozzles, pump and valve trim, paper and textile equipment components. These materials are formed by encapsulation of sic particles in a silicon nitride matrix, by nitridation of silicon at high temperatures under a nitrogen atmosphere. Silicon carbide refractory castables article in refractories and industrial ceramics 466. Development and study of directbonded silicon carbide bricks as a. Silicon carbide shapes are a very versatile refractory base material.
Silicon carbide refractory castables request pdf researchgate. Silicon nitridebonded silicon carbide snbsc has been widely used in metallurgical and chemical industry as advanced refractories and hightemperature structure materials. The modern method of manufacturing silicon carbide for the abrasives, metallurgical, and refractories industries is basically the same as that developed by acheson. A mixture of pure silica sand and carbon in the form of finely ground coke is built up around a carbon conductor within a brick electrical resistancetype furnace. Refractory products plasticplastic gunning plasticgunning plastic gunning castablegunning castable. Nitride bonded silicon carbide brick north refractories co. We keep large stocks of various high temperature alloys like 310, 330, 800, 601 and 625 in shapes such as round bars, flat bars, plates and round wire so we can confidently offer you short delivery times. Silica bricks consist of 90 percent by weight of sio in general, the sio. Most claybased products are processed in a manner similar to other traditional ceramics such as structural clay products.
520 174 881 1239 852 1239 1609 883 1032 996 762 1276 1568 1467 379 1381 552 941 1575 841 1629 1000 1090 1565 458 1374 429 300 1616 525 1248 458 1188 1386 505 1135 1441 494 631 353 945