METHOD OF MAKING ARTICLES FROM POROUS CERAMIC AND FIBRE MATERIALS BASED ON QUARTZ GLASS Russian patent published in 2014 - IPC C04B35/14 

FIELD: chemistry.

SUBSTANCE: method of making articles involves making a porous article of given size and shape, completely or partially depositing a ceramic refractory coating from an aqueous suspension on the surface and hardening. The 0.5-5.0 mm thick coating is deposited in form of a ceramic layer on the surface of the article with open porosity of not less than 7% in 5-100 min from a suspension based on quartz glass with a modifying refractory additive in form of a powder of oxide and (or) oxygen-free materials, e.g. Si₃N₄, Si, SiB₄, Cr₂O₃, CoO, TiO₂, ZrB₂, SiC, the total amount of which is not more than 50% by solid phase. The aqueous suspension has a polydisperse grain composition in the range of 0.5-500 mcm with content of particles smaller than 5 mcm of 20-40%, particles larger than 63 mcm of 1-10%, moisture content of 15-18%, and the coating is hardened by autoclave treatment of the article in a steam autoclave with volume ratio of steam and ammonia vapour of 1:0.05-0.20, temperature of 100-250°C and pressure of 0.5-10.0 atm. The article is then dried in an air medium at temperature of 50-150°C.

EFFECT: high strength, thermophysical and chemical properties of the articles.

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