Salt silicon carbides

Silicon is important to plant and animal life. Diatoms in both fresh and salt water extract Silica from the water to build their cell walls. Silica is present in the ashes of plants and in the human skeleton. Silicon is an important ingredient in steel silicon carbide is one of the most important abrasives and has been used in lasers to produce coherent light of 4560 A. 

Vapor decomposition (14,15) iavolves dryiag, decomposiag, and vaporising a spray of salt precursor solution ia a plasma, and subsequentiy nucleating and growing ceramic particles ia the vapor. Silicon carbide [12504-67-5] SiC, powder is produced by this method. 

The high-temperature stability of SiC-based ceramics is well-known, and therefore its composite materials have been investigated for application to high-tem-perature structural materials [19-21]. However, well-known SiC-based fibers and matrix-materials stained with alkali salt are easily oxidized at high temperatures in air [22]. This would be a serious problem when these materials are used near the ocean or in a combustion gas containing alkali elements. In particular, a silicon carbide fiber containing boron (a well-known sintering aid for SiC) over 1 wt% was extensively oxidized under the above condition. In this... 

Silicon carbide is prepared by heating fine sdica with carbon (coke) and a little salt and sawdust in an electric furnace. 

Silicon carbide. Silicon carbide (SiC), more familiarly known by the trade name Carborundum, is produced by heating a mixture of coke, sawdust, sand, and salt to about 3000°C in an electric furnace ... 

Some ceramic materials are not found widely or at all in nature, and thus are synthesized for use. To prepare more complex ceramic compositions such as perovskites of general structural formula ABO3, and ferrites, of formula MFc204, the individual oxides or salts of the cations A, B, and M are often combined as powders and then reacted at high temperature by a solid-state diffusion mechanism. Silicon nitride (Si3N4) can be manufactured from either the nitridation of silicon metal or from the reaction of silicon tetrachloride with ammonia. Silicon carbide (SiC) is obtained from the reduction of silica with a carbon containing source. 

PZCs/IEPs of sparingly soluble salts (other than combination of two or more sparingly soluble oxides) are presented in Tables 3.1568 through 3.1910. PZCs/IEPs of silicon carbide and nitride are also presented in this section. Salt-type compounds composed entirely of sparingly soluble oxides are discussed in Section 3.3. In the studies devoted to the effect of water-soluble salts with an anion or cation in common with the sparingly soluble salt of interest, the IEP has been defined in terms of concentration of these salts (ions) in addition to (or rather than) pH. 

Silicon carbide is made by the chemical reaction, in an electric fiirnace, of high carbon coke and pure silica sand, with small amounts of salt and sawdust added to assist the reactions. The resultant mass is crushed to give... 

Examples of volatile nonmetallic compounds are very familiar methane, ammonia, water. Examples of involatile compounds are silicon carbide (SiC) and silica (Si02). The former is manufactured by heating silica with graphite and is sold under the name carborundum. The commereial produet is black, but when pure it is colourless. It melts at about 2700 C. Pure silica also forms colourless crystals, melting to a colourless liquid at about 1600 °C and boiling at about 2400 C. Both compounds are insulators. Conductivity measurements have also been made on liquid silica, in which state it remains a poor conductor (cf salt-like compounds). 

Owing to the fact that valence electrons determine bonds, the electrical properties of a material are related to the bond type. In conductors such as metals, alloys, and intermetallics, the atoms are bound to each other primarily by metallic bonds, and metals such as tungsten or aluminum are good conductors of electrons or heat. Covalent bonds occur in insulators such as diamond and silicon carbide and in semiconductors such as silicon or gallium arsenide. Complexes and salts have ions that are bound with electrostatic forces. Ionic conductors can be used as solid electrolytes for fuel cells because solids with ionic bonds may have mobile ions. Most polymers have covalent bonds in their chains but the mechanical... 

PA production received a further innovative impetus from the use of an alternative feedstock. In 1944/45, for the first time, Oronite Chemical Co. Standard Oil CA)) in the USA oxidized o-xylene in a salt-bath reactor to produce PA. The catalyst was a low-porosity carrier (silica quartz or silicon carbide), which was coated with 7 to 8% molten V2O5. The reaction temperatures of 450 to 600 °C were considerably higher than those used in the process. 

The use of phosphates for ceramic bonding was patented in 1931 by Morgan [6]. Phosphoric acid [7] and its salts have since been used to bond numerous refractory materials, including kaolin, fireclay, alumina, magnesia, chromite, silica, sillimanite, zircon, silicon carbide and graphite. Bonding in these materials results, in part, from the formation of small quantities of phosphates of Al, Mg, Cr, Si, Zr and so on. 

Other unusual additives include oxetanes, vinylic macromono-mers, silicon carbide, superconductive carbon blacks, silver-coated fly ash, metal oxides, Tb for green emission, antibacterial agents, and organic-inorganic hybrid copolymer fibers. In an interesting reversal, transition element acetylacetonate salts were decomposed in a PDMS matrix to give membranes with catalytic activity. ... 

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