A method for forming ceramic matrix composite (CMC) component includes forming a fiber preform, positioning the fiber preform into a chemical vapor infiltration reactor chamber, and densifying the fiber preform. Densification includes infiltrating the fiber preform with a first gas comprising precursors of silicon carbide and infiltrating the fiber preform with a second gas comprising a first rare earth element, wherein the steps of infiltrating the fiber preform with the first gas and infiltrating the fiber preform with the second gas are conducted simultaneously to produce a first rare earth-doped silicon carbide matrix in a first region of the component.

Cordierite-forming batch mixtures including one or more non-oxide inorganic source materials or materials as pore-formers are provided. Non-oxide inorganic materials, such a non-oxide silicon material that includes at least one of silicon carbide, silicon, or silicon nitride, may be added to cordierite-forming batch mixtures as at least a partial replacement for conventional inorganic pore-formers. Non-oxide inorganic pore-formers may provide an increase in pore volume while having a reduced coefficient of thermal expansion impact as compared with conventional pore-formers. Cordierite-forming mixtures as disclosed herein may additionally include rare-earth catalysts and alkaline-earth materials that may enhance the pore-forming effect of non-oxide inorganic pore-formers without significant exothermic reactions or the production of emissions that may require additional processing treatments.

Among two main surfaces of a heat dissipation member, one main surface is curved to be convex in an outward direction and the other convex in an inward direction. When a straight line passing through both endpoints P.sub.1 and P.sub.2 of the curve is l.sub.1, a point at which a distance to l.sub.1 on the curve is maximum is P.sub.max, an intersection point between l.sub.1 and a perpendicular drawn from P.sub.max to l.sub.1 is P.sub.3, a middle point of a line segment P.sub.1P.sub.3 is P.sub.4, an intersection point between the curve and a straight line that passes through P.sub.4 and is perpendicular to l.sub.1 is P.sub.mid, a length of the line segment P.sub.1P.sub.3 is L, a length of a line segment P.sub.3P.sub.max is H, and a length of a line segment P.sub.4P.sub.max is h, (2 h/L)/(H/L) is 1.1 or more.

A reaction-bonded silicon carbide (SiC) body is produced by: providing a preform including ceramic elements and carbon, and one or more surface features; providing a powder which includes diamond particles and carbon; locating the powder in the surface feature(s); and infiltrating the preform and the powder with molten silicon (Si) to form reaction-bonded SiC in the preform, and to form reaction-bonded SiC coatings on the diamond particles. The present disclosure also relates to a device/component which includes: a main body portion and discrete elements located at least partially within the main body portion. The main body portion may include reaction-bonded SiC and Si, but not diamond, while the discrete elements include diamond particles, reaction-bonded SiC coatings surrounding the diamond particles, and Si. According to the present disclosure, diamond may be advantageously located only where it is needed.

A ceramic composite can include a first ceramic phase and a second ceramic phase. The first ceramic phase can include a silicon carbide. The second phase can include a boron carbide. In an embodiment, the silicon carbide in the first ceramic phase can have a grain size in a range of 0.8 to 200 microns. The first phase, the second phase, or both can further include a carbon. In another embodiment, at least one of the first ceramic phase and the second ceramic phase can have a median minimum width of at least 5 microns.

The present disclosure provides a ceramic powder having low bulkiness and good dispersibility. In the ceramic powder, the volume ratio of aggregated particles having a particle diameter larger than a reference particle diameter is 35 vol. % or more and the volume ratio when ultrasonic dispersion treatment for 10 minutes at an oscillation frequency of 19.5 kHz and an output power of 10 W is applied is 4 vol. % or less. The reference particle diameter is a particle diameter equivalent to a cumulative 0.1 vol. % diameter from the large diameter side when the ceramic powder is subjected to ultrasonic dispersion treatment for 3 minutes at an oscillation frequency of 19.5 kHz and an output power of 150 W.

A negative electrode active material including a silicon-carbon-based particle, the silicon-carbon-based particle having a SiC.sub.x matrix and boron doped in the SiC.sub.x matrix, wherein x of the SiC.sub.x matrix is 0.3 or more and less than 0.6.

Described are molds that include a ceramic material at a surface, as well as methods of forming the molds, and methods of using the molds; the ceramic material is constituted substantially, mostly, or entirely of three elemental components designated M, A, and X; the “M” component is at least one transition metal; the “A” component is one or a combination of Si, Al, Ge, Pb, Sn, Ga, P, S, In, As, Tl, and Cd; and the “X” component is carbon, nitrogen, or a combination thereof.

An antiballistic armor-plating component, includes a ceramic body made of a material comprising, as percentages by volume, between 35% and 55% of silicon carbide, between 20% and 50% of boron carbide, between 15% and 35% of a metallic silicon phase or of a metallic phase including silicon.

A ceramic matrix composite includes a ceramic matrix, fibers embedded in the ceramic matrix, and an interfacial coating system on each of the fibers. The interfacial coating system includes alternating layers of boron nitride layers of individual thicknesses of about 50 nanometers to 200 nanometers and carbon layers of individual thicknesses of less than 5 nanometers.