Abstract: Silicon nitride powder may be prepared by subjecting a composite comprising at least a monolayer of a carbonaceous pyropolymer possessing recurring units containing at least carbon and hydrogen atoms on the surface of a silica support to the action of nitrogen-containing atmospheres at nitriding conditions to form silicon nitride.

Abstract: Refractory materials which replicate a substantial portion of the internal pore structure as well as the shape and dimensions of high surface area microporous substrate materials which comprise metal or metalloid carbides may be prepared by uniformly depositing a carbide-forming metal or metalloid on the internal surfaces of a high surface area microporous carbon-donor substrate material in the vapor phase. By controlling the operating parameters when depositing carbide-forming metal or metalloid, it is possible to effect a balance between the diffusion rate of the metal or metalloid-containing compound in the structure pores of the substrate with the decomposition rate of the compound, thus obtaining a uniform deposition of the metal or metalloid. If so desired, the substrate material may be subsequently removed by chemical or oxidative means.

Abstract: Apparatus and method for detecting and measuring chloride ion and therefore dissociable chlorine compounds using a solid electrolyte concentration cell. Applicable only to gaseous samples.

Abstract: Carbonaceous pyropolymers possessing recurring units containing at least carbon and hydrogen atoms composited on a solid support may be prepared in a solid state process. The process is effected by treating a high surface area solid support such as an inorganic oxide as exemplified by alumina with an organic monomer which is capable of being polymerized by thermal, ionic, or free radical polymerization methods. The monomer is polymerized on the surface of the support under polymerization conditions and thereafter the polymer-coated support is subjected to pyrolysis at temperatures ranging from about 600.degree. to about 1200.degree. C. to form a carbonaceous pyropolymer. If so desired, this composite may then be subjected to the action of a dissolving agent under conditions which will dissolve or leach out the solid support, thus leaving a carbonaceous pyropolymer possessing recurring units containing at least carbon and hydrogen atoms.

Abstract: Integral shaped replication composites which may be useful for supports for catalysts or as adsorbents comprise a carbonaceous pyropolymeric structure which has been prepared by treating an inorganic support with an organic pyropolymer precursor and pyrolyzing the precursor to form a carbonaceous pyropolymer possessing recurring units containing at least carbon and hydrogen atoms on the surface of the support. This carbonaceous pyropolymer will duplicate the physical shape and dimensions of the inorganic support as well as a substantial portion of the pore structure thereof. The integral shaped replication will possess an ABD which is about 25% to 100% of the ABD of the inorganic support, and have a crush strength of from about 0.5 to about 14 kilograms. The composite comprising the carbonaceous pyropolymer on the surface of the support may then be leached with an acid or base to remove the inorganic support, thus leaving a shaped replication of particle aggregates.

Abstract: Electrocatalysts which may be used in the preparation of electrodes for electrochemical cells such as fuel cells comprise a carbonaceous pyropolymer having the surface thereof impregnated with at least one catalytically active metal. The electrocatalysts may be prepared by treating a refractory inorganic oxide with a pyrolyzable organic compound at pyrolysis conditions to form a carbonaceous pyropolymer on the surface of said refractory inorganic oxide. Thereafter the composite may be impregnated with a soluble salt of at least one catalytically active metal and thereafter the composite may be leached to remove the refractory inorganic oxide. Alternatively, the composite may be leached to remove the refractory inorganic oxide prior to impregnation with the catalytically active metal.

Abstract: Oxygen sensor incorporating a thin film electrolyte such as yttria stabilized zirconia sputtered onto a substrate produces an electrical signal in response to differences in oxygen partial pressures. The electrical signal changes rapidly enough for useful operation at temperatures which are substantially lower than those required by conventional oxygen sensors having a rigid, self-supporting thimble, tubular, or disc type electrolyte. For example, rapidly responding signals have been generated at temperatures below 200.degree. C whereas state of the art devices such as those used for sensing exhaust gases in automotive vehicles require temperatures higher than about 400.degree. C.