Abstract: The invention relates to a method of manufacturing an anti-oxidation system for porous ceramics on the basis of SiC or Si.sub.3 N.sub.4. By means of infiltration into the pore inner spaces of a sol containing at least one metal component, conversion of the sol to a gel (sol-gel process) and a subsequent high-temperature treatment, it is possible successfully to provide a crystalline anti-oxidation layer, which is resistant to temperatures of up to at least 1650.degree. C. even under cyclic temperature stresses, and reveals a heat expansion behavior adapted to the SiC or Si.sub.3 N.sub.4 over the entire temperature range used.

Abstract: A device for supporting flat ceramic objects, particularly glazed floor or wall tiles, to be fired in a continuous heating furnace where the objects can be moved on rollers which are in the form of tubes. These tubes are equipped with raised and indented portions with the objects to be fired only being supported by the raised portions during transport through the furnace.