Surface protection of porous ceramic bodies

摘要

A surface of a porous ceramic body is protected by binding ceramic particles entirely within the subsurface porosity of the body adjacent to the surface but not present as a separately identifiable surface layer. To produce such a protective layer, a slurry of a mixture of a ceramic powder and a silica-containing binding agent is first prepared. The slurry is impregnated into the surface of the body so that all of the slurry enters the porosity of the body and substantially none of the slurry resides on the surface. The slurry is dried in place, and the residual solids are fired to bind the ceramic powder to the interior walls of the porosity. Drying and firing can be accomplished at intermediate temperatures of about 700 DEG -1000 DEG F. using heat lamps, so that the surface protection can be accomplished without removing the ceramic body from a larger structure.