A carbon-carbon composite preform including a plurality of layers including carbon fibers or carbon-precursor fibers, the layers include a first exterior layer defining a first major surface, a second exterior layer defining a second major surface, and at least one interior layer disposed between the first exterior layer and the second exterior layer, the at least one interior layer having a peripheral region that forms a portion of an outer surface of the preform. The preform includes needled fibers, where at least some needled fibers extend through two or more layers. The preform has an exterior region and a core region, where the exterior region includes at least the peripheral region of at least one interior layer. The needled fibers define a first needled fiber number density (NFND) in the exterior region and a second greater NFND in at least a portion of the core region.

A multilayer substrate that includes a first ceramic layer that is a dense body, a second ceramic layer that has open pores, and a resin layer adjacent the second ceramic layer, wherein a material of the resin layer is present in the open pores of the second ceramic layer.

A method to form a machinable ceramic matrix composite comprises forming a porous ceramic multilayer on a surface of a fiber preform. In one example, the porous ceramic multilayer comprises a gradient in porosity in a direction normal to the surface. In another example, the porous ceramic multilayer includes low-wettability particles having a high contact angle with molten silicon, where an amount of the low-wettability particles in the porous ceramic multilayer varies in a direction normal to the surface. After forming the porous ceramic multilayer, the fiber preform is infiltrated with a melt, and the melt is cooled to form a ceramic matrix composite with a surface coating thereon. An outer portion of the surface coating is more readily machinable than an inner portion of the surface coating. The outer portion of the surface coating is machined to form a ceramic matrix composite having a machined surface with a predetermined surface finish and/or dimensional tolerance.

Described herein is a gaslight multilayered composite tube having a heat transfer coefficient of >500 W/m.sup.2/K which in its construction over the cross section of the wall of the composite tube includes as an inner layer a nonporous monolithic oxide ceramic surrounded by an outer layer of oxidic fiber composite ceramic, where this outer layer has an open porosity of 5%<ε<50%, and which on the inner surface of the composite tube includes a plurality of depressions oriented towards the outer wall of the composite tube. Also described herein is a method of using the multilayered composite tube as a reaction tube for endothermic reactions, jet tubes, flame tubes or rotary tubes.

Disclosed is a ceramic matrix component having a fibrous core and a ceramic matrix composite shell surrounding at least a portion of the fibrous core. The ceramic matrix composite shell comprises a fibrous preform. The fibrous core has a greater porosity than the fibrous preform. A method of making the ceramic matrix component is also disclosed.

A vaporization core of an electronic vaporization device includes: a porous ceramic substrate; a ceramic covering layer; and a heating film. The ceramic covering layer is combined on a surface of the porous ceramic substrate. The heating film is combined on a surface of the ceramic covering layer away from the porous ceramic substrate. A porosity of the ceramic covering layer is lower than a porosity of the porous ceramic substrate. A plurality of penetrating holes are formed on the ceramic covering layer.

Provided are a composite ceramic member and a method for preparation thereof, a vaporization assembly, and an electronic cigarette. The composite ceramic member comprises a first ceramic layer, a second ceramic layer, and a third ceramic layer stacked in sequence; in the first ceramic layer, the second ceramic layer, and the third ceramic layer, the first ceramic layer has the smallest pore size and the highest thermal conductivity, the second ceramic layer has the largest porosity, and the third ceramic layer has the highest compressive strength.

A composite material manufacturing method includes: laminating a first sheet (210) including a first slurry (214) and a third sheet (230) including a third slurry (234); and heating the first sheet (210) and the third sheet (230) that are laminated to a temperature of transforming to ceramics by pyrolysis to form an intermediate body (300). The manufacturing method further includes impregnating the intermediate body (300) with a slurry and heating at a temperature lower than a temperature of transforming to ceramics by pyrolysis.

Production of multilayered ceramic missile radomes with wide frequency band and high electromagnetic permeability through three-dimensional printing technology and the use of glass inter-layer materials to minimize defects caused by thermo-mechanical incompatibility of adjacent layers during sintering are provided. The three dimensional printing of the multilayered ceramic missile radomes provide an automated, operator-independent and repeatable manufacturing technique to produce wide band ceramic missile radomes.

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.