Provided is polycrystalline diamond having a diamond single phase as basic composition, in which the polycrystalline diamond includes a plurality of crystal grains and contains boron, hydrogen, oxygen, and the remainder including carbon and trace impurities; the boron is dispersed in the crystal grains at an atomic level, and greater than or equal to 90 atomic % of the boron is present in an isolated substitutional type; hydrogen and oxygen are present in an isolated substitutional type or an interstitial type in the crystal grains; each of the crystal grains has a grain size of less than or equal to 500 nm; and the polycrystalline diamond has a surface covered with a protective film.

Methods for fabricating a ceramic matrix composite are disclosed. A fiber preform may be placed in a mold. An aqueous solution may be added to the fiber preform. The aqueous solution may include water, carbon nanotubes, and a binder. The preform may be frozen. Freezing the preform may cause the water to expand and separate fibers in the fiber preform. The carbon nanotubes may bond to the fibers. The preform may be freeze dried to remove the water. The preform may then be processed according to standard CMC process.

An indenter is made of polycrystalline diamond and has a tip having a spherical surface with a radius of 10 to 2000 m.

A method of forming titanium boron alloys includes forming a mixture of elemental titanium with elemental boron and heating the mixture with a laser, wherein a power level of the laser is set such that reaction of the elemental titanium with the elemental boron to form a titanium-boron alloy is initiated and self-sustaining.

A shaped composite body of a reaction-bonded, silicon-infiltrated mixed ceramic, the microstructure of which is determined by primary grains of crystalline B.sub.4C grains (1) of mean grain size d50>100 ?m and <500 ?m and a fraction of >10%, by weight, and <50%, by weight, and by primary grains of a finer silicon carbide with d50<70 ?m and a fraction of >10%, by weight, and <50%, by weight, and the primary grains are siliconized (3) bonded by secondarily formed silicon carbide with a fraction of >5%, by weight and <25%, by weight, in a silicon carbide matrix having a free metallic silicon (2) content of >1%, by weight, and <20%, by weight.

A method for the manufacture of a carbon composite comprises compressing a combination comprising carbon and a binder at a temperature of about 350 C. to about 1200 C. and a pressure of about 500 psi to about 30,000 psi to form the carbon composite; wherein the binder comprises a nonmetal, metal, alloy of the metal, or a combination thereof wherein the nonmetal is selected from the group consisting of SiO.sub.2, Si, B, B.sub.2O.sub.3, and a combination thereof; and the metal is selected from the group consisting of aluminum, copper, titanium, nickel, tungsten, chromium, iron, manganese, zirconium, hafnium, vanadium, niobium, molybdenum, tin, bismuth, antimony, lead, cadmium, selenium, and a combination thereof.

Disclosed is a composition having nanoparticles or particles of boron, a refractory metal, or a refractory metal hydride; organic compound having a char yield of at least 60% by weight or a thermoset made from the organic compound; and a reinforcing material. The metal and organic are combined with the reinforcing material. The mixture is heated for make a ceramic having nanoparticles of a boron or refractory metal nitride, boride, or carbide; a reinforcing material; and a carbonaceous matrix. The ceramic is not a powder.

Disclosed is a composition having nanoparticles or particles of a refractory metal, a refractory metal hydride, a refractory metal carbide, a refractory metal nitride, or a refractory metal boride, an organic compound consisting of carbon and hydrogen, and a nitrogenous compound consisting of carbon, nitrogen, and hydrogen. The composition, optionally containing the nitrogenous compound, is milled, cured to form a thermoset, compacted into a geometric shape, and heated in a nitrogen atmosphere at a temperature that forms a nanoparticle composition comprising nanoparticles of metal nitride and optionally metal carbide. The nanoparticles have a uniform distribution of the nitride or carbide.

The present invention relates to a porous alpha-SiC-containing shaped body with a gas-permeable, open-pored pore structure comprising platelet-shaped crystallites which are connected to form an interconnected, continuous skeletal structure, wherein the skeletal structure consists of more than 80 wt.-% alpha-SiC, relative to the total weight of SiC, a process for producing same and its use as a filter component.

A method for fabricating a ceramic material includes impregnating a porous structure with a mixture that includes a preceramic polymer and a filler. The filler includes at least one free metal. The preceramic polymer material is then rigidized to form a green body. The green body is then thermally treated to convert the rigidized preceramic polymer material into a ceramic matrix located within pores of the porous structure. The same thermal treatment or a second, further thermal treatment is used to cause the at least one free metal to move to internal porosity defined by the ceramic matrix or pores of the porous structure.