A hard material which, when used as a material of a sintered material, makes it possible to obtain a sintered material with excellent abrasion resistance, a sintered material, a cutting tool including the sintered material, a method for manufacturing the hard material and a method for manufacturing the sintered material are provided. The hard material contains aluminum, nitrogen, and at least one element selected from the group consisting of titanium, chromium, and silicon, and has a cubic rock salt structure.

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 system and method for forming a porous ceramic preform is provided. The method may include forming a stacked powder structure including a binder layer and a powder layer on the binder layer. The binder layer may be formed by depositing a binder with a spray nozzle on a substrate. The powder layer may be formed by depositing a powder on the binder layer. The porous ceramic preform may be formed by heating the stacked powder structure to pyrolyze the binder. The porous ceramic preform is configured to be infiltrated by a molten material. The substrate may comprise a ceramic fiber preform. After melt infiltration of the porous ceramic preform and the ceramic fiber preform, a densified ceramic feature having a predetermined geometry may be formed on a ceramic matrix composite (CMC) component.

A system and method for forming a porous ceramic preform is provided. The method may include forming a stacked powder structure including a binder layer and a powder layer on the binder layer. The binder layer may be formed by depositing a binder with a spray nozzle on a substrate. The powder layer may be formed by depositing a powder on the binder layer. The porous ceramic preform may be formed by heating the stacked powder structure to pyrolyze the binder. The porous ceramic preform is configured to be infiltrated by a molten material. The substrate may comprise a ceramic fiber preform. After melt infiltration of the porous ceramic preform and the ceramic fiber preform, a densified ceramic feature having a predetermined geometry may be formed on a ceramic matrix composite (CMC) component.

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 “ΔE*ab”, a relation “ΔE*ab≤1.5” is established.

The invention relates to a method for manufacturing a composite component of a timepiece or of a jewelry part, the composite component comprising a porous ceramic part and a metallic material filling the pores of said ceramic part, said method comprising the steps of: providing a porous ceramic preform of the component, providing a metallic material, heating the metallic material to a temperature higher than the melting point of the metallic material, filling the pores of the ceramic preform with the molten metallic material, cooling the metallic material and the ceramic preform to obtain a solidified metallic material in the pores of the ceramic preform, and applying finishing treatments to obtain the composite component,

wherein said porous ceramic preform consists essentially of a material selected from the group consisting of Si.sub.3N.sub.4, SiO.sub.2 and mixtures thereof, and said metallic material is selected from the group consisting of gold, platinum, palladium metals and alloys of these metals.

The invention relates also to a composite component of a timepiece or of a jewelry part comprising a porous ceramic part and a metallic material filling the pores of said ceramic part, wherein said porous ceramic part consists essentially of a material selected from the group consisting of Si.sub.3N.sub.4, SO.sub.2 and mixtures thereof, and said metallic material which is selected from the group consisting of gold, platinum, palladium metals and alloys of these metals.

The invention relates to a method for manufacturing a composite component of a timepiece or of a jewelry part, the composite component comprising a porous ceramic part and a metallic material filling the pores of said ceramic part, said method comprising the steps of: providing a porous ceramic preform of the component, providing a metallic material, heating the metallic material to a temperature higher than the melting point of the metallic material, filling the pores of the ceramic preform with the molten metallic material, cooling the metallic material and the ceramic preform to obtain a solidified metallic material in the pores of the ceramic preform, and applying finishing treatments to obtain the composite component,

wherein said porous ceramic preform consists essentially of a material selected from the group consisting of Si.sub.3N.sub.4, SiO.sub.2 and mixtures thereof, and said metallic material is selected from the group consisting of gold, platinum, palladium metals and alloys of these metals.

The invention relates also to a composite component of a timepiece or of a jewelry part comprising a porous ceramic part and a metallic material filling the pores of said ceramic part, wherein said porous ceramic part consists essentially of a material selected from the group consisting of Si.sub.3N.sub.4, SO.sub.2 and mixtures thereof, and said metallic material which is selected from the group consisting of gold, platinum, palladium metals and alloys of these metals.

A structure according to the embodiment includes a first crystal grain, a second crystal grain, and a first region. The first crystal grain includes silicon nitride. The second crystal grain includes a first element selected from a first group consisting of scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, aluminum, chromium, zirconium, magnesium, zinc, titanium, gallium, beryllium, calcium, strontium, barium, hafnium, vanadium, niobium, tantalum, tungsten, iron, cobalt, nickel, and copper, and oxygen. The first region includes an oxide of the first element.

The invention relates to an axial turbine with a rotating casing and stationary shaft, sections for the assembly thereof, and materials for the manufacture thereof.