Methods of forming a carbon fiber reinforced carbon foam are provided. Such a method may comprise heating a porous body composed of a solid material comprising covalently bound carbon atoms and heteroatoms and having a surface defining pores distributed throughout the solid material, in the presence of an added source of gaseous hydrocarbons. The heating generates free radicals in the porous body from the heteroatoms and induces reactions between the free radicals and the gaseous hydrocarbons to form covalently bound carbon nanofibers extending from the surface of the solid material and a network of entangled carbon microfibers within the pores the porous body, thereby forming a carbon fiber reinforced carbon foam. Carbon fiber reinforced carbon foams and ballistic barriers incorporating the foams are also provided.

It is an object of the present disclosure to provide a thin-film carbon foam and a method of manufacture the same. It is another object of the present disclosure to provide a stack carbon foam having fewer through holes and a method of manufacturing the same. The carbon foam of the present disclosure is, for example, a stack carbon foam being a stack of at least two monolayer carbon foams stacked one another, each monolayer carbon foam comprising linear portions and node portions joining the linear portions, or a carbon foam comprising linear portions and node portions joining the linear portions, wherein the ratio of the number of large through holes having a diameter of 1 mm or more to the surface area of the carbon foam is 0.0003/mm.sup.2 or less.

It is an object of the present disclosure to provide a thin-film carbon foam and a method of manufacture the same. It is another object of the present disclosure to provide a stack carbon foam having fewer through holes and a method of manufacturing the same. The carbon foam of the present disclosure is, for example, a stack carbon foam being a stack of at least two monolayer carbon foams stacked one another, each monolayer carbon foam comprising linear portions and node portions joining the linear portions, or a carbon foam comprising linear portions and node portions joining the linear portions, wherein the ratio of the number of large through holes having a diameter of 1 mm or more to the surface area of the carbon foam is 0.0003/mm.sup.2 or less.

A porous ceramic structure intended to form the reinforcement of a ceramic matrix composite component, the structure having a connected porosity delimited by an internal surface which includes a plurality of first points, each first point being associated with a second point aligned with this first point along a normal to the internal surface taken at the first point, the structure being divisible into a plurality of unit volumes of a size less than or equal to 5 mm3 in each of which: a characteristic pore length, corresponding to the maximum of the distance separating each first point from its associated second point, is less than or equal to 0.5 mm; and a porosity ratio is greater than or equal to 50%.

A porous ceramic structure intended to form the reinforcement of a ceramic matrix composite component, the structure having a connected porosity delimited by an internal surface which includes a plurality of first points, each first point being associated with a second point aligned with this first point along a normal to the internal surface taken at the first point, the structure being divisible into a plurality of unit volumes of a size less than or equal to 5 mm3 in each of which: a characteristic pore length, corresponding to the maximum of the distance separating each first point from its associated second point, is less than or equal to 0.5 mm; and a porosity ratio is greater than or equal to 50%.

The present invention addresses the problem of providing: a porous carbon structure that has a high micropore volume and can be self-contained; a manufacturing method therefor; a positive electrode material using the same; and a battery (particularly an air battery) using the same. The present invention is a porous carbon structure that is for a positive electrode for an air battery and has voids and a skeleton formed by incorporating carbon, the porous carbon structure satisfying all of the following conditions (a) to (d). (a) The t-plot external specific surface area is within the range of 300m.sup.2/g to 1600m.sup.2/g; (b) the total volume of micropores having a diameter of lnm to 200 nm is within the range of 1.2 cm.sup.3/g to 7.0cm.sup.3/g; (c) the total volume of micropores having a diameter of lnm to 1000 nm is within the range of 2.3cm3/g to 10.0 cm.sup.3/g; and (d) the overall porosity is within the range of 80% to 99%.

The present invention addresses the problem of providing: a porous carbon structure that has a high micropore volume and can be self-contained; a manufacturing method therefor; a positive electrode material using the same; and a battery (particularly an air battery) using the same. The present invention is a porous carbon structure that is for a positive electrode for an air battery and has voids and a skeleton formed by incorporating carbon, the porous carbon structure satisfying all of the following conditions (a) to (d). (a) The t-plot external specific surface area is within the range of 300m.sup.2/g to 1600m.sup.2/g; (b) the total volume of micropores having a diameter of lnm to 200 nm is within the range of 1.2 cm.sup.3/g to 7.0cm.sup.3/g; (c) the total volume of micropores having a diameter of lnm to 1000 nm is within the range of 2.3cm3/g to 10.0 cm.sup.3/g; and (d) the overall porosity is within the range of 80% to 99%.

In one aspect, composite carbide compositions are described herein which can facilitate the efficient and/or economical manufacture of articles comprising SiC. Briefly, a composite carbide composition comprises silicon carbide (SiC) particles and a silica interparticle phase covalently bonded to the SiC particles.

In one aspect, composite carbide compositions are described herein which can facilitate the efficient and/or economical manufacture of articles comprising SiC. Briefly, a composite carbide composition comprises silicon carbide (SiC) particles and a silica interparticle phase covalently bonded to the SiC particles.

Nanoporous carbon-based scaffolds or structures, and specifically carbon aerogels and their manufacture and use thereof are provided. Embodiments include a silicon-doped anode material for a lithium-ion battery, where the anode material includes beads of a polyimide-derived carbon aerogel. The carbon aerogel may further include silicon particles and accommodates expansion of the silicon particles during lithiation. The anode material provides optimal properties for use within the lithium-ion battery.