The present invention relates to a process for the production of fiber-reinforced composite materials with an ultra-refractory, high tenacity, high ablation resistant matrix with self-healing properties, prepared from highly sinterable slurries. The composite material is produced using techniques of infiltration and drying at ambient pressure or under vacuum, and consolidated by sintering with or without the application of gas or mechanical pressure.

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.

A composite material and a method of using the composite material. The composite material consists of at least 65 volume percent cubic boron nitride (cBN) grains dispersed in a binder matrix, the binder matrix comprising a plurality of microstructures bonded to the cBN grains and a plurality of intermediate regions between the cBN grains; the microstructures comprising nitride or boron compound of a metal; and the intermediate regions including a silicide phase containing the metal chemically bonded with silicon; in which the content of the silicide phase is 2 to 6 weight percent of the composite material, and in which the cBN grains have a mean size of 0.2 to 20 μm.

To provide a surface-coated cutting tool exhibiting excellent wear resistance in a high-speed cutting process and having prolonged service life. The surface-coated cutting tool includes a tool substrate containing WC crystal grains and insulating grains, and a coating layer composed of a multiple nitride of Ti, Al, and V and disposed on the surface of the tool substrate. The multiple nitride is represented by a compositional formula: Ti.sub.aAl.sub.bV.sub.cN satisfying the following relations:

0.25≤a≤0.35,

0.64≤b≤0.74,

0<c≤0.06, and

a+b+c=1

(wherein each of a, b, and c represents an atomic proportion). The coating layer is characterized by exhibiting a peak attributed to a hexagonal crystal phase and a peak attributed to a cubic crystal phase as observed through X-ray diffractometry.

A method for forming in situ a boron nitride reaction product locally on a reinforcement phase of a ceramic matrix composite material includes the steps of providing a ceramic matrix composite material having a fiber reinforcement material; and forming in situ a layer of boron nitride on the fiber reinforcement material.

A porous material includes aggregate particles and a binding material. In the aggregate particles, oxide films containing cristobalite are provided on surfaces of particle bodies that are silicon carbide particles or silicon nitride particles. The binding material contains cordierite and binds the aggregate particles together in a state where pores are provided therein. The mass ratio of the cordierite to the whole of the porous material is in the range of 10 to 40 mass %. The oxide films that exist between the particle bodies and the binding material have a thickness less than or equal to 0.90 μm.

A cubic boron nitride sintered material comprises 30% by volume or more and 80% by volume or less of cubic boron nitride grains and 20% by volume or more and 70% by volume or less of a binder phase, the cubic boron nitride grains having a dislocation density of 3×10.sup.17/m.sup.2 or more and 1×10.sup.20/m.sup.2 or less.

A ceramic containing, in mass %: Si.sub.3N.sub.4: 20.0 to 60.0%, ZrO.sub.2: 25.0 to 70.0%, at least one selected from SiC and AlN: 2.0 to 17.0%, where AlN is 10.0% or less, at least one selected from MgO, Y.sub.2O.sub.3, CeO.sub.2, CaO, HfO.sub.2, TiO.sub.2, Al.sub.2O.sub.3, SiO.sub.2, MoO.sub.3, CrO, CoO, ZnO, Ga.sub.2O.sub.3, Ta.sub.2O.sub.5, NiO and V.sub.2O.sub.5: 5.0 to 15.0%, wherein Fn calculated from the following equation (1) satisfies 0.02 to 0.40. This ceramic can be laser machined with high efficiency.

Fn=(SiC+3AlN)/(Si.sub.3N.sub.4+ZrO.sub.2)  (1)

A preceramic resin formulation comprising a polycarbosilane preceramic polymer, an organically modified silicon dioxide preceramic polymer, and, optionally, at least one filler. The preceramic resin formulation is formulated to exhibit a viscosity of from about 1,000 cP at about 25° C. to about 5,000 cP at a temperature of about 25° C. The at least one filler comprises first particles having an average mean diameter of less than about 1.0 μm and second particles having an average mean diameter of from about 1.5 μm to about 5 μm. Impregnated fibers comprising the preceramic resin formulation are also disclosed, as is a composite material comprising a reaction product of the polycarbosilane preceramic polymer, organically modified silicon dioxide preceramic polymer, and the at least one filler. Methods of forming a ceramic matrix composite are also disclosed.

A method for manufacturing a part made of composite material includes forming a ceramic matrix phase in pores of a fibrous preform by pyrolysis of a cross-linked copolymer ceramic precursor, the cross-linked copolymer including a first precursor macromolecular chain of a first ceramic having free carbon, and a second precursor macromolecular chain of a second ceramic having free silicon, the first macromolecular chain being bonded to the second macromolecular chain by cross-linking bridges including a bonding structure of formula *.sup.1—X—*.sup.2; in this formula, X designates boron or aluminium, -*.sup.1 designates the bond to the first macromolecular chain and -*.sup.2 the bond to the second macromolecular chain.