Abstract: The present invention relates to a molding material for the precision casting and dead-mold casting of metals or metal alloys comprising plastic and/or carbon aerogels, and a process for the preparation of such molding materials. The molding material comprises highly porous open-cell plastic and/or carbon aerogels, obtainable by the sol-gel polymerization of organic plastic materials, optionally followed by partial or complete pyrolysis of the plastic aerogel obtained.

Abstract: The present invention relates to a molding material for the precision casting and dead-mold casting of metals or metal alloys comprising plastic and/or carbon aerogels, and a process for the preparation of such molding materials.

Abstract: The present invention relates to a molding material for the precision casting and dead-mold casting of metals or metal alloys comprising plastic and/or carbon aerogels, and a process for the preparation of such molding materials. The molding material comprises highly porous open-cell plastic and/or carbon aerogels, obtainable by the sol-gel polymerization of organic plastic materials, optionally followed by partial or complete pyrolysis of the plastic aerogel obtained.

Abstract: A thin, flat, and porous carbon gas diffusion electrode having a side in contact with a supply of gas and a side in contact with an electrolyte, comprises a pyrolysis product of a composite of an organic aerogel or xerogel and a reinforcing skeleton consisting at least in part of organic material. The porosity of the carbon gas diffusion electrode according to the invention can be regulated at will while the surface of the electrode is smooth.

Abstract: A method of making porous ceramics of lead titanate (PT) or lead zirconate PZT) of a Pb(Zr.sub.x Ti.sub.1-x) O.sub.3 compound from a gel made by mixing at least 2.5 equivalents of water based on the compound with a solution prepared from a polar solvent having complexing and chelating properties, one or more Pb(II) and PB(IV) carboxylates and at least one compound including titanium and zirconium of the general formula M(OR).sub.4 where M is titanium or zirconium and R is similar or different groups representing at least one of a straight chain, cross-linked and cyclic alkyl and alkenyl group with 1 to 10 carbon atoms, aging the resulting gel beyond its gel point, replacing the solvent in the pores of the gel by a chelating solvent, drying the resulting gel under supercritical conditions and tempering the resulting aerogel.

Abstract: SiO.sub.2 aerogels containing carbon particles are obtainable by heatinga) organically modified SiO.sub.2 aerogels in the presence of at least one pyrolyzable hydrocarbon gas and/or at least one inert gas orb) organically unmodified SiO.sub.2 aerogels in the presence of at least one pyrolyzable hydrocarbon gas and in the presence or absence of inert gases to 600.degree.-1300.degree. C.

Abstract: A thermal insulating material based on a pigment-containing silica aerogel is obtainable bya) reacting an aqueous dispersion of sodium silicate and a pigment with a strong acid or sodium silicate with a pigment-containing strong acid to give a pigment-containing silica hydrogen, the pigment being such that it scatters, absorbs or reflects infrared radiation of wavelength 3-10 .mu.m,b) substantially freeing the resulting pigment-containing silica hydrogel from ionic constituents by washing with water,c) displacing the water in the hydrogen by a low-boiling liquid which is inert toward the pigment-containing silica gel,d) heating the liquid-containing silica gel thus obtained under supercritical conditions while completely covered with the liquid, ande) subsequently removing the liquid from the solid by flash vaporization at supercritical temperature.