Thermal oxidation of silicon carbide with surface modification by the molecular layering method

Corundum-silicon carbide-bearing concrete parts made using a liquid glass binder

“…Therefore, in order to ensure sufficient strength of the corundum--silicon carbide-bearing concrete product during its service, it is necessary to create a large volume of open porosity in the material at 700-I000~ for facilitating penetration of atmospheric oxygen (Kainarskii [17] recommends open charging of the silicon carbide products during the firing operation), to use the method of chemically modifyingthe surface of the waste products of the thermal insulation charge [18] etc.…”

Kinetics of the combustion of carbon in graphite chamotte articles

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Graphite-containing refractories have become widely used in recent years [1][2].The technical solution in the field of production of these refractories envisages special conditions for the slowing down of the carbon-oxidation process in the products: firing in a neutral or reducing medium; glazing of the articles [3]; the addition of ferrosilicon or silicon to the batch to bind the carbon as silicon carbide; additives to produce a liquid phase [4]; and so on.One of the ways of controlling the resistance of the materials to oxidation is to chemically modify the surface of the SiC powder by molecular modification of the surface [5,6].The extent of the combustion of carbon in graphite-containing refractories depends largely on the structure of the refractory and the operational temperature.The kinetics of the carbon combustion in unfired graphite-containing high-alumina articles heated from 800 to 1600~ was studied and also the character of the carbon combustion in various directions and at various distances from the surface of the articles was investigated.Specimens in the form of cylinders 25 mmindiameter and height were molded from low-and high-carbon masses* [7] using a semidry pressing method at a pressure of 40 MPa. The batch of the low-carbon articles included 15% of Polozhsk kaolin, 20% of laminar graphite, 45% of highalumina chamotte (-82% AI~03), and 20% of SI-65 ferrosilicon; the batch for the high-carbon articles contained the same components but in the following amounts, respectively: 15, 50, 15, and 20%, To i00 parts of the batch we added 8 parts each of AKPS and 4 parts of distillery waste.

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“…One of the ways of controlling the resistance of the materials to oxidation is to chemically modify the surface of the SiC powder by molecular modification of the surface [5,6].…”