A method includes providing a ceramic fiber preform with a range of 20 to 40 volume percent fiber which can include silicon carbide fibers; coating the ceramic fiber preform with a boron nitride interface coating; infiltrating the ceramic fiber preform with a ceramic matrix with a range of 20 to 40 volume percent silicon carbide; infiltrating the ceramic fiber preform with a constituent material such as boron carbide, boron, and carbon; and infiltrating the ceramic fiber preform with a eutectic melt material where the metallic eutectic melt can include at least one material from a group consisting of: a transition metal-silicon eutectic melt such as zirconium silicide, a transition metal-boride eutectic melt such as zirconium boride, and a transition metal-carbide eutectic melt such as zirconium carbide.

A method includes providing a ceramic fiber preform with a range of 20 to 40 volume percent fiber which can include silicon carbide fibers; coating the ceramic fiber preform with a boron nitride interface coating; infiltrating the ceramic fiber preform with a ceramic matrix with a range of 20 to 40 volume percent silicon carbide; infiltrating the ceramic fiber preform with a constituent material such as boron carbide, boron, and carbon; and infiltrating the ceramic fiber preform with a eutectic melt material where the metallic eutectic melt can include at least one material from a group consisting of: a transition metal-silicon eutectic melt such as zirconium silicide, a transition metal-boride eutectic melt such as zirconium boride, and a transition metal-carbide eutectic melt such as zirconium carbide.

A composition having nanoparticles of a boron carbide and a carbonaceous matrix. The composition is not in the form of a powder. A composition comprising boron and an organic component. The organic component is an organic compound having a char yield of at least 60% by weight or a thermoset made from the organic compound. A method of combining boron and an organic compound having a char yield of at least 60% by weight, and heating to form boron carbide or boron nitride nanoparticles.

To provide: a silicon nitride sintered body having excellent mechanical property and imparting superior lifetime to a product into which the silicon nitride sintered body is processed; a machine part using the silicon nitride sintered body; and a bearing. The silicon nitride sintered body: has the crystallinity of 75-90% calculated by the following formula based on an XRD diffraction pattern on a mirror-polished cutting face of the silicon nitride sintered body; contains one element or more of Y, Ce, Nd and Eu in an amorphous phase; and does not have an inclusion having a diameter of more than 50 m and a pore having a diameter of more than 50 m in a surface layer portion.

Crystallinity (%)=Crystalline peak area/(Crystalline peak area+Amorphous peak area)100

To provide: a silicon nitride sintered body having excellent mechanical property and imparting superior lifetime to a product into which the silicon nitride sintered body is processed; a machine part using the silicon nitride sintered body; and a bearing. The silicon nitride sintered body: has the crystallinity of 75-90% calculated by the following formula based on an XRD diffraction pattern on a mirror-polished cutting face of the silicon nitride sintered body; contains one element or more of Y, Ce, Nd and Eu in an amorphous phase; and does not have an inclusion having a diameter of more than 50 m and a pore having a diameter of more than 50 m in a surface layer portion.

Crystallinity (%)=Crystalline peak area/(Crystalline peak area+Amorphous peak area)100

A composition having nanoparticles of a boron carbide and a carbonaceous matrix. The composition is not in the form of a powder. A composition comprising boron and an organic component. The organic component is an organic compound having a char yield of at least 60% by weight or a thermoset made from the organic compound. A method of combining boron and an organic compound having a char yield of at least 60% by weight, and heating to form boron carbide or boron nitride nanoparticles.

A composition having nanoparticles of a boron carbide and a carbonaceous matrix. The composition is not in the form of a powder. A composition comprising boron and an organic component. The organic component is an organic compound having a char yield of at least 60% by weight or a thermoset made from the organic compound. A method of combining boron and an organic compound having a char yield of at least 60% by weight, and heating to form boron carbide or boron nitride nanoparticles.

According to a method set forth herein a plurality of preform plies having first and second preform plies can be associated together to define a preform. The preform can be subject to chemical vapor infiltration (CVI) processing to define a ceramic matrix composite (CMC) structure.

A method for a fabricating a ceramic material includes providing a mixture of a reactive metallic filler material with a preceramic polysilazane material. The preceramic polysilazane material is then polymerized to form a green body. The green body is then thermally treated in an environment that is substantially free of oxygen to convert the polymerized preceramic polysilazane material into a ceramic material that includes at least one nitride phase that is a reaction product of the reactive metallic filler material and a preceramic polysilazane material.

A method for a fabricating a ceramic material includes providing a mixture of a reactive metallic filler material with a preceramic polysilazane material. The preceramic polysilazane material is then polymerized to form a green body. The green body is then thermally treated in an environment that is substantially free of oxygen to convert the polymerized preceramic polysilazane material into a ceramic material that includes at least one nitride phase that is a reaction product of the reactive metallic filler material and a preceramic polysilazane material.