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New families of high-temperature composite materials:
refsic, refsicoat and refsicut.
B.A. Gnesin
High-temperature materials are of a great importance for modern techniques and technology development. Such materials are necessary for energetic, traditional and nuclear ones, in aviation and space techniques, in metallurgy, ceramics and glass industries. They are required in a lot of technologies dealing with high temperatures, for example: for processing of chemical productions waste, for production of ceramics, for decomposing of dioxins, generated during processing of rubbish and in many other cases.
In Institute of Solid State Physics of Russian Academy of Sciences (ISSP RAS) refsic, refsicoat and refsicut new families of high-temperature composite materials were invented and developed last years. These materials are distinguished one self by high level of high-temperature strength, antioxidant properties at high temperature, high hardness and high stability in thermal shock conditions.
тАв€а Mechanical properties of refsic and refsicut materials are high up to 1900€ђ †С and even at higher temperatures.
тАв€а Refsic and refsicoat materials are corrosion resistant on air up to 1900€ђ †С and even at higher temperatures.
тАв€а With a help of refsicoat materials it is possible to prepare protective antioxidant coatings workable up to 1900€ђ †С on carbon materials and on alloys of refractory metals.
тАв€а With a help of refsicoat it is possible to join by brazing refractory metals, carbon materials, silicon carbide materials, refsic and refsicut materials in any possible combinations.
Listed particulars of proposed materials opens new possibilities not only in development and production of new composite materials, but in design and production of many new devices and supplies, impossible to prepare earlier without refsic, refsicoat and refsicut materials.
Refsic, refsicoat and refsicut materials are patented by ISSP RAS in Russia (€µ€µ 2160790; 2178958; 2232736) and in the USA (€µ 6,589,898 †и €µ6,770,856). They are also patented in other countries (Europe, Canada, Japan, Israel )
Refsic, refsicoat and refsicut materials have already revealed their advantages in following applications:
High-temperature electric heaters.
Main advantages of electric heaters with refsic and refsicoat materials are determined not only by properties of working parts of heaters but also by using of brazing to join parts of a heater:
тАв€а working parts and current leaders may posses more than two orders of value difference in specific electric resistivity that helps to diminish unnecessary losses of electric energy in current leaders ;
тАв€а contact parts of current leaders may consists of graphite and it helps to have a reliable contact with electric feeders;
тАв€а heaters may be heated and cooled with velocities 4-20 times higher than silicon carbide and molybdenum disilicide based heaters, including many of heatings-coolings cycles, in many applications it is important ;
тАв€а possible temperatures on electric heaters reaches 1600€ђC and some times 2000€ђC and even more;.
тАв€а high level of specific thermal flow is typical for our heaters: up to 60 W/cm2 form a calm air and up to 180 W/cm2 for air flow
тАв€а heaters are workable in any position and orientation
тАв€а refsic made working parts are not subjected to creep
The most of our orders to refsic heaters are connected with applications, were it is impossible to use traditional silicon carbide and MoSi2 heaters. As usual, there are some rigid demands to temperature distribution on heater we try to fulfil.
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Instruments for grinding
High hardness (up to 28-30 GPa), high abrasive ability and high resistance to wear of refsic and refsicut material are retained up to 1600-2000€ђC and it allows to produce different grinding instrument. Temperature on a rigid edge of such instrument may be higher than for usual grinding instruments (for example, cutting and grinding wheels) on hundreds of Centigrade and it is especially important for high speed and high efficient machines. For glass and ceramic grinding instrument it is possible to recommend refsicut grinding tools, very steady and not so expensive as diamond tools.
Moulds for pressing
It is possible to prepare moulds for pressing using refsic , refsicoat and refsicut materials for cold and hot pressing of metals and plastics.
Aviation and space applications
A combination of properties for refsic , refsicoat and refsicut materials makes them interesting to use in parts undergoing thermal flows of high intensity. These materials revealed the record level of stability during supersonic gaseous flame tests. It is possible to produce parts with very complex structure and even with internal channels and connected pores, penetrable for gaseous and liquid flows
Wear resistant electric- spark deposited coatings
Refsic and refsicoat materials made electrodes may be used to produce hard, wear resistant and corrosion resistant electric-spark deposited coatings on steels and iron, on titanium alloys and in other cases. Such coatings twice and more arises wear resistance of cutting instruments (for example for wood).
Electric- spark coatings for foundry forms and moulds
After deposition of electric-spark coatings with a help of refsicoat electrodes on inside surface of moulds, lingots and parts of machine for continuous casting of ferrous and nonferrous metals, service time arises twice and more! Simultaneously, level of iron impurities in a casted metal is significantly diminished. Ingots are stripped easily Tests on iron moulds for copper and nickel alloys casting were successful.
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Possible applications of refsic , refsicoat and refsicut materials
(stage of tests)
Brake blocks
Refsicut materials may be recommended for brake blocks for high velocity transport. Due to high stability in local overheating conditions, this material can cancel high impulse quickly.
Split face seals
Service time of refsicut materials made split face seals used for different pumps (oil, gas condensate and chemical materials), is significantly higher than this for silicon carbide seals, prepared with a help of traditional technology.
Wear resistant electric-spark deposited coatings
Refsic and refsicoat materials made electrodes may be used to produce hard, wear resistant and corrosion resistant electric-spark deposited coatings on steels, iron and titanium alloys. Such coatings are able to increase significantly stability of valves for vapor systems in power stations. They may be recommended for turbine blades repair.
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Wear resistant electric arc deposited coatings
Refsic materials made electrodes may be used to produce hard, wear resistant and corrosion resistant electric arc deposited coatings on steels and titanium alloys. These coatings are deposited on air without protection atmosphere or fluxes. Such coatings may be recommended for parts of mining, road building and building machinery and for increasing of stability of valves.
We are interested to :
тАв€а orders on experimental batches of articles produced with a help of refsic , refsicoat and refsicut materials;
тАв€а to sell license on producing on production and technology of refsic , refsicoat and refsicut materials;
тАв€а orders on R&D oriented on design of new patentable technical products, using refsic , refsicoat and refsicut materials.