Abstract: In some examples, a method of making a filter includes heating a metal substrate to precipitate a first phase on a surface of the metal substrate from a metal alloy, the metal substrate defining a plurality of apertures configured to allow a gas to pass through the apertures. The metal substrate is the metal alloy including a first metal and a second metal. The method further includes growing a plurality of carbon nanotubes (CNTs) on the surface of the first metal of the first phase, and the CNTs are configured to capture at least one particle.

Abstract: In some examples, a method of making a filter includes heating a metal substrate to precipitate a first phase on a surface of the metal substrate from a metal alloy, the metal substrate defining a plurality of apertures configured to allow a gas to pass through the apertures. The metal substrate is the metal alloy including a first metal and a second metal. The method further includes growing a plurality of carbon nanotubes (CNTs) on the surface of the first metal of the first phase, and the CNTs are configured to capture at least one particle.

Abstract: An article including carbon-carbon composite substrate may be treated with an antioxidant coating prior to use in an oxidizing environment. The antioxidant coating may be configured to reduce oxidation at an external surface of the C-C composition and reduce ingress of oxidants into pores or other open passages defined by the C-C composite substrate to avoid internal oxidation. An example article includes a C-C composite substrate, a bond coat, and an antioxidant coating. The C-C composite substrate defines a friction surface and a non-friction surface. The bond coat is disposed on the non-friction surface. The antioxidant coating may be disposed on at least a portion of the bond coat. The antioxidant coating may include ytterbium disilicate and a sintering aid.

Abstract: The disclosure describes in some examples a technique that includes the disclosure describes a technique that includes depositing a carbon powder and a resin powder on a surface of a fiber preform, where the fiber preform includes a plurality of fibers and defines interstitial spaces between the plurality of fibers, and vibrating the fiber preform to allow the carbon powder and the resin powder to infiltrate the interstitial spaces between the plurality of fibers of the fiber preform to form an infiltrated preform.

Abstract: The disclosure describes in some examples a technique that includes aligning a plurality of carbon preform segments in a staggered arrangement, where each carbon preform segment of the plurality carbon preform segment includes a carbon body including at least one of a plurality of carbon fibers or a carbon foam, and a silicon-based mixture including silicon particles. The techniques may include heating the staggered arrangement to react the silicon particles with the carbon body to bond the plurality of carbon preform segments together and form a ceramic matrix composite component.

Abstract: In some examples, an article may include a carbon-carbon composite, an antioxidant in pores in a surface of the carbon-carbon composite, and a hydrophobic coating on the surface. The hydrophobic coating includes an oxide of a metal. The metal has a Pauling electronegativity of less than about 1.7. In some examples, the article may be a carbon-carbon composite brake disk that includes a carbon-carbon composite substrate defining a friction surface and a non-friction surface. The antioxidant may be a phosphate-based antioxidant, and the antioxidant may be in pores in the non-friction surface. In some examples, the hydrophobic coating is on the non-friction surface over the phosphate-based antioxidant. In some examples, the hydrophobic coating may include a majority of at least one of yttrium oxide, scandium oxide, or zirconium oxide.

Abstract: The disclosure describes in some examples a technique that includes aligning a plurality of carbon preform segments in a staggered arrangement, where each carbon preform segment of the plurality carbon preform segment includes a carbon body including at least one of a plurality of carbon fibers or a carbon foam, and a silicon-based mixture including silicon particles. The techniques may include heating the staggered arrangement to react the silicon particles with the carbon body to bond the plurality of carbon preform segments together and form a ceramic matrix composite component.

Abstract: The disclosure describes in some examples a technique that includes the disclosure describes a technique that includes depositing a carbon powder and a resin powder on a surface of a fiber preform, where the fiber preform includes a plurality of fibers and defines interstitial spaces between the plurality of fibers, and vibrating the fiber preform to allow the carbon powder and the resin powder to infiltrate the interstitial spaces between the plurality of fibers of the fiber preform to form an infiltrated preform.

Abstract: In some examples, an article may include a carbon-carbon composite, an antioxidant in pores in a surface of the carbon-carbon composite, and a hydrophobic coating on the surface. The hydrophobic coating includes an oxide of a metal. The metal has a Pauling electronegativity of less than about 1.7. In some examples, the article may be a carbon-carbon composite brake disk that includes a carbon-carbon composite substrate defining a friction surface and a non-friction surface. The antioxidant may be a phosphate-based antioxidant, and the antioxidant may be in pores in the non-friction surface. In some examples, the hydrophobic coating is on the non-friction surface over the phosphate-based antioxidant. In some examples, the hydrophobic coating may include a majority of at least one of yttrium oxide, scandium oxide, or zirconium oxide.

Abstract: A piston shoe (10) of an axial piston pump or motor is crimped to an annular piston head (42) and has a flat shoe wear surface (12) that contacts a cam plate (22). A back flange (14) of the shoe (10) also wears against an auxilliary cam plate (24). In order for the piston shoe (10) to operate within a fuel environment, the piston shoe (10) must be corrosion resistant, compatible with fuel, and provide the desired wear resistance. The piston shoe (10) is made of a cold workable cobalt based alloy which is compatible with fuel and provides corrosion resistance. The wear surface (12) which bears against the cam plate (22) and the back flange (14) which bears against the auxilliary cam plate (24) are provided with a thermal diffusion boride treatment which provides the desired wear resistance. In order to restore sufficient ductility to flange (16) of the shoe (10) that will be cold worked, a solution treatment is performed at a temperature range of 2050.degree. to 2250.degree. F. in a non-oxidizing environment.