The sliding member according to the embodiment includes a silicon nitride sintered body that includes silicon nitride crystal grains and a grain boundary phase, in which a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains among any 50 of the silicon nitride crystal grains having completely visible contours in a 50 μm×50 μm observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 10%. The percentage is more preferably not less than 0% and not more than 3%.

The sliding member according to the embodiment includes a silicon nitride sintered body that includes silicon nitride crystal grains and a grain boundary phase, in which a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains among any 50 of the silicon nitride crystal grains having completely visible contours in a 50 μm×50 μm observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 10%. The percentage is more preferably not less than 0% and not more than 3%.

Disclosed are a 3D printing material, a preparation method and use thereof. The 3D printing material is linear, and it comprises, in percent by volume, 16 to 82% of a non-metal material, 17.9 to 83% of a first binder and 0.1 to 1% of a second binder. The material is obtained by pre-treating the non-metallic material, then mixing with the first binder, and extruding.

Disclosed are a 3D printing material, a preparation method and use thereof. The 3D printing material is linear, and it comprises, in percent by volume, 16 to 82% of a non-metal material, 17.9 to 83% of a first binder and 0.1 to 1% of a second binder. The material is obtained by pre-treating the non-metallic material, then mixing with the first binder, and extruding.

A method of producing a CMC having a smooth surface includes forming a fiber preform; rigidizing the preform with an interphase coating; infiltrating a ceramic slurry into the preform to form a green body; conducting secondary operations on the green body; applying a slurry-based layer onto a portion of the green body; and infiltrating the green body with a molten silicon or silicon alloy, such that the CMC exhibits a smooth surface. The application of the slurry-based surface layer onto the green body includes placing the green body into a tool fixture having upper and lower components, such that a gap is present between the green body and at least one of the upper and lower components; and delivering a surface layer slurry into at least one gap, such that the surface layer slurry forms the slurry-based layer on at least a portion of the green body.

A method of producing a CMC having a smooth surface includes forming a fiber preform; rigidizing the preform with an interphase coating; infiltrating a ceramic slurry into the preform to form a green body; conducting secondary operations on the green body; applying a slurry-based layer onto a portion of the green body; and infiltrating the green body with a molten silicon or silicon alloy, such that the CMC exhibits a smooth surface. The application of the slurry-based surface layer onto the green body includes placing the green body into a tool fixture having upper and lower components, such that a gap is present between the green body and at least one of the upper and lower components; and delivering a surface layer slurry into at least one gap, such that the surface layer slurry forms the slurry-based layer on at least a portion of the green body.

A method of producing a CMC component that includes forming a preform having a plurality of ceramic fiber plies with each ply occupying a predetermined position; rigidizing the preform with a fiber interphase coating; inspecting the preform to determine which of the plies has partially or fully delaminated; reworking the delaminated plies in the preform; infiltrating a ceramic slurry into the preform to form a green body; optionally, conducting a secondary operation on the green body; and infiltrating the green body with a molten silicon or silicon alloy to form the CMC component. The step of reworking delaminated plies may also be applied to a green body formed after ceramic slurry infiltration into a rigidized fiber preform.

Provided is a composite ceramic layered body, including: a substrate; and a composite ceramic that coats the substrate, the composite ceramic including a nitride phase and an oxide phase having an elastic modulus that differs from an elastic modulus of the nitride phase by 10% or more. The composite ceramic includes, among the nitride phase and the oxide phase, a first phase that occupies a largest area ratio, and a toughening phase that occupies an area ratio of 1% or more and has a largest difference in elastic modulus from an elastic modulus of the first phase. In a case in which the first phase is the nitride phase, the toughening phase is the oxide phase, and in a case in which the first phase is the oxide phase, the toughening phase is the nitride phase.

Provided is a composite ceramic layered body, including: a substrate; and a composite ceramic that coats the substrate, the composite ceramic including a nitride phase and an oxide phase having an elastic modulus that differs from an elastic modulus of the nitride phase by 10% or more. The composite ceramic includes, among the nitride phase and the oxide phase, a first phase that occupies a largest area ratio, and a toughening phase that occupies an area ratio of 1% or more and has a largest difference in elastic modulus from an elastic modulus of the first phase. In a case in which the first phase is the nitride phase, the toughening phase is the oxide phase, and in a case in which the first phase is the oxide phase, the toughening phase is the nitride phase.

A probe card board in the present disclosure includes a plurality of through holes designed to receive a probe brought into contact with a measurement object. The probe card board is composed of silicon nitride based ceramics. The probe card board includes a first surface opposed to the measurement object and a second surface located opposite to the first surface. The probe card board contains a plurality of crystal phases of metal silicide. Metal constituting the metal silicide is at least one kind selected from among molybdenum, chrome, iron, nickel, manganese, vanadium, niobium, tantalum, cobalt and tungsten.