In some examples, a method for making a refractory component includes depositing carbon on a surface of a refractory substrate. The carbon fills surface voids on the surface of the refractory substrate. A melting point of the refractory substrate is greater than or equal to about 1500 degrees Celsius ( C.). The method includes applying a metal slurry to a surface of the refractory substrate following the deposition of the carbon and reacting a metal of the metal slurry with the carbon to form a metal carbide phase within the surface voids of the refractory substrate.

In some examples, a method for making a refractory component includes depositing carbon on a surface of a refractory substrate. The carbon fills surface voids on the surface of the refractory substrate. A melting point of the refractory substrate is greater than or equal to about 1500 degrees Celsius ( C.). The method includes applying a metal slurry to a surface of the refractory substrate following the deposition of the carbon and reacting a metal of the metal slurry with the carbon to form a metal carbide phase within the surface voids of the refractory substrate.

The silicon nitride sintered body according to the present disclosure contains silicon nitride particles and yttrium silicon oxynitride particles and has a porosity of 14% or less.

The silicon nitride sintered body according to the present disclosure contains silicon nitride particles and yttrium silicon oxynitride particles and has a porosity of 14% or less.

A silicon nitride ceramic material for a mobile phone rear cover and a preparation method therefor. The method comprises: using a mixture of a silicon source, a colorant, and a sintering aid as raw materials, mixing the raw material components, and performing shaping and sintering to obtain the silicon nitride ceramic material. The toughness of the silicon nitride ceramic material can reach more than 12 MPa.Math.m.sup.1/2; the thermal conductivity thereof can reach 40 to 70 W/m.Math.K; and a dielectric loss thereof is 10.sup.4.

A silicon nitride ceramic material for a mobile phone rear cover and a preparation method therefor. The method comprises: using a mixture of a silicon source, a colorant, and a sintering aid as raw materials, mixing the raw material components, and performing shaping and sintering to obtain the silicon nitride ceramic material. The toughness of the silicon nitride ceramic material can reach more than 12 MPa.Math.m.sup.1/2; the thermal conductivity thereof can reach 40 to 70 W/m.Math.K; and a dielectric loss thereof is 10.sup.4.

A preparation method for a copper plate-covered silicon nitride ceramic substrate is provided. The structure of the copper plate-covered silicon nitride ceramic substrate includes a silicon nitride ceramic substrate, copper sheets disposed on the upper and lower sides of the silicon nitride ceramic substrate and soldering layers disposed between the copper sheets and the silicon nitride ceramic substrate; the composition of the silicon nitride ceramic substrate comprises a silicon nitride phase (more than or equal to 95 wt %); and a grain boundary phase (containing at least three elements (Y, Mg and O) and less than or equal to 5 wt %, and the content of a crystalline phase in the grain boundary phase is more than or equal to 40 vol %); and the sintering aids are Y.sub.2O.sub.3 and MgO. The two-step sintering process comprises: in a nitrogen atmosphere, performing low-temperature heat treatment and high-temperature heat treatment in sequence.

A ceramic composite sealing ring, high-pressure compressor of a gas turbine engine assembly including a ceramic composite sealing ring and method for making a high-pressure compressor of a gas turbine engine assembly. The ceramic composite material is composed of unidirectional aligned fibers which may be encapsulated by a ceramic matrix. The piston seal ring of the high-pressure compressor of a gas turbine engine assembly is positioned at the interface of the tie shaft and the integrated blade rotor.

A method for limiting void formation in a melt-infiltrated ceramic matrix composite (MI-CMC) component includes arranging one or more infiltrant feedstocks in fluid communication with a targeted area of the MI-CMC component. The one or more infiltrant feedstocks have a nominal melting point at or below a nominal melting point of an alloy within the MI-CMC component. The method includes heating the one or more infiltrant feedstocks to a first temperature at or above the nominal melting point of the one or more infiltrant feedstocks to form a molten phase. The method also includes infiltrating the targeted area of the MI-CMC component with the molten phase. As such, the molten phase reacts with a solid phase in the targeted area of the MI-CMC component. Further, the method includes cooling the MI-CMC component to a second temperature that is below the first temperature to solidify the molten phase.

Color unevenness generated on a surface of a silicon nitride substrate is reduced. A silicon nitride substrate formed by nitriding silicon containing in a sheet-shaped green body includes a first surface and a second surface opposite to the first surface. In this case, when color difference between a center and an edge of at least one surface of the first surface and the second surface is expressed to be E*ab, a relation E*ab1.5 is established.