The disclosure describes a method for forming a surface layer of a ceramic matrix composite (CMC) article. The technique includes depositing a slurry on a surface of an infiltrated CMC. The slurry includes a carrier material, a binder, a plasticizer, and solid particles. The solid particles include a plurality of fine ceramic particles defining a fine particle average size less than about 5 micrometers. The method further includes drying the slurry to form an article having an outer surface layer that includes the solid particles on the infiltrated CMC. The method further includes machining at least a portion of the outer surface layer of the article. The method further includes infiltrating the article with a molten infiltrant to form a composite article.

A method may include depositing a sacrificial support material on or adjacent to a build surface. The sacrificial support material may be configured to support a continuous reinforcement material during an additive manufacturing technique. The method also may include extruding the continuous reinforcement material from an additive manufacturing device such that at least a portion of the continuous reinforcement material contacts and is supported by the sacrificial support material; and removing the sacrificial support material to result in a feature defined at least in part by the continuous reinforcement material at the absence of sacrificial support material.

The object of the present invention is to provide a large-sized gallium nitride-based sintered body having a small oxygen amount and high strength, a large-sized gallium nitride-based sintered body having a small oxygen amount and containing a dopant, to obtain a highly crystalline gallium nitride thin film which has become a n-type or p-type semiconductor by a dopant, and methods for producing them.

A gallium nitride-based sintered body, which has an oxygen content of at most 1 atm % and an average particle size (D50) of at least 1 μm and at most 150 μm.

A sintered material includes a first phase and a second phase, wherein the first phase is composed of cubic boron nitride particles, and the following relational expressions are satisfied when more than or equal to two cubic boron nitride particles adjacent to and in direct contact with each other among the cubic boron nitride particles are defined as a contact body, Di represents a length of an entire perimeter of the contact body, n represents the number of contact locations at which the cubic boron nitride particles are in direct contact with each other, d.sub.k represents a length of each of the contact locations, and Σd.sub.k (where k=1 to n) represents a total length of the contact locations: Dii=Di+(2×Σd.sub.k (where k=1 to n)); and [(Dii−Di)/Dii]×100≤50.

The present disclosure discloses a hybrid woven fiber preform-reinforced composite material, including a fiber preform, a composite material interface and a matrix, where the fiber preform is a three-dimensional fabric hybrid woven by 2-5 high-performance inorganic fibers, and the matrix is selected from the group consisting of resin, light alloy, carbon and ceramic. A preparation method of the composite material includes: preparing ceramic slurry, fiber bundle impregnation treatment, fiber weaving, molding of three-dimensional overall structure preform, preform heat treatment, preparing interface and preparing matrix. The present disclosure improves the weaving performance of inorganic rigid fibers, and the prepared hybrid woven fiber preform-reinforced composite material has desirable integrity, high interlayer bonding strength, and is not easy to layer. Meanwhile, the present disclosure realizes the functions of wave transmission, wave-absorbing, high-temperature structural material, thermal insulation and thermal prevention through the combination of hybrid woven fibers.

The present disclosure discloses a continuous electrophoretic deposition modified carbon fiber reinforced multi-matrix composite and a preparation method thereof, composing of a carbon fiber with a volume fraction of 30-55%, an inorganic powder with a volume fraction of 3-25% and a matrix with a volume fraction of 20-67%, wherein the inorganic powder is wrapped on the surface of the carbon fiber filament or embedded in the carbon fiber bundle, and the concentration gradually decreases from the fiber filament to the surface of the fiber bundle. The preparation method of the composite is as follows: (1) pretreating the carbon fibers; (2) preparing a slurry of the inorganic powder; (3) widening the pretreated carbon fiber to form a carbon fiber strip, and then carrying out electrophoretic deposition on the inorganic powders; (4) preparing a preform from the deposited carbon fibers; and (5) compounding a matrix in the preform.

A silicon nitride-based sintered body containing silicon nitride-based grains, which are silicon nitride grains or sialon grains. In the silicon nitride-based sintered body, when the size of each silicon nitride-based grain is represented by its maximum grain size, the ratio of the number of silicon nitride-based grains having a maximum grain size of 1 μm or less to the number of the entire silicon nitride-based grains is 70% or higher. Furthermore, in the distribution profile of no. % of silicon nitride-based grains with respect to maximum grain size, the maximum value of no. % (i.e., maximum no. %) of silicon nitride-based grains is 15 no. % or higher. Also disclosed is a cutting insert, which is formed of the silicon nitride-based sintered body.

The invention relates to a sliding member having a first sliding surface, wherein the first sliding surface (29) comprises a particulate support material (6) and a graphene-containing material (7), wherein the particulate support material (6) is at least partially coated with the graphene-containing material (7), and wherein a material bond (14) is present between the particulate support material (6) and the graphene-containing material (7).

A silicon nitride substrate includes silicon nitride and magnesium, in which when a surface of the silicon nitride substrate is analyzed with an X-ray fluorescence spectrometer under the specific Condition I, XB/XA is 0.8 or more and 1.0 or less.

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.