Abstract:
A disclosed method of forming a ceramic article includes forming a pre-ceramic polymer article within a mold tool, and performing a first pyrolizing step on the initial pre-ceramic polymer article to form a ceramic article. The method further includes performing at least one pre-heat treatment polymer infiltration and pyrolizing (PIP) cycle on the ceramic article and an initial heat treatment cycle of the ceramic article after the at least one pre-heat treatment PIP cycle. Subsequent PIP cycles and heat treatment cycles are performed in combination to form a ceramic article including a desired density.
Abstract:
A nanocellular foam has pores, interconnecting ligaments, and nodes where three or more ligaments intersect. The ligament cross section thickness is less than 200 microns and the distance between nodes is less than 1000 microns. A method of fabricating a nanocellular foam comprising forming a compact with one or more powders and applying energy to cause at least one or more powders to undergo a change in state is disclosed.
Abstract:
A solid-state method for forming an alloy includes providing a powder that has heterogeneous particles with a ratio, by weight, of an amount of nickel to an amount of a metal. The ratio is selected in accordance with a compositional ratio that can substantially bear a nickel intermetallic precipitate of the nickel and the metal. The heterogeneous particles are then consolidated and thermally treated to interdiffuse the nickel and the metal. The interdiffused nickel and metal are then precipitation treated to precipitate the nickel intermetallic.
Abstract:
Disclosed is a method for providing a crystalline ceramic material. In an example, the method includes providing a silicon-containing preceramic polymer material that can be thermally converted to one or more crystalline polymorphs. The silicon-containing preceramic polymer material includes dispersed therein an effective amount of dopant particles. The silicon-containing preceramic polymer material is then thermally converted to the silicon-containing ceramic material. The effective amount of dopant particles enhance the formation of at least one of the one or more crystalline polymorphs, relative to the silicon-containing preceramic polymer without the dopant particles, with respect to at least one of formation of a selected polymorph of the one or more crystalline polymorphs formed, an amount formed of a selected polymorph of the one or more crystalline polymorphs formed, and a temperature of formation of the one or more crystalline polymorphs.
Abstract:
An article includes a ceramic-based substrate and a barrier layer on the ceramic-based substrate. The barrier layer includes a matrix of barium-magnesium alumino-silicate or SiO2, a dispersion of silicon oxycarbide particles in the matrix, and a dispersion of particles, of the other of barium-magnesium alumino-silicate or SiO2, in the matrix.
Abstract:
An article includes a silicon oxycarbide-based layer that has Si, O, and C in a covalently bonded network. The silicon oxycarbide-based layer has first and second opposed surfaces. A calcium-magnesium alumino-silicate-based layer is interfaced with the first surface of the silicon oxycarbide-based layer.
Abstract:
A method of fabricating a ceramic article includes serially depositing first, second and third different materials within a porous structure using, respectively, first, second and third different processing techniques, to form a ceramic-containing article. The first, second and third materials differ by at least one of composition and microstructure. The first, second and third different processing techniques differ by at least one of modes of delivery of precursor materials into the porous structure and formation mechanisms of the first, second and third different materials from the precursor materials. The deposition of the first material is controlled such that there are first residual voids in the porous structure in which the second material is deposited. The deposition of a second material is controlled such that there are second residual voids in the porous structure in which the third material is deposited.
Abstract:
A method of producing a ceramic material includes heating solid silicon monoxide to provide gaseous silicon monoxide, and exposing a structure having a free-carbon-containing material to the gaseous silicon monoxide to convert free carbon of the free-carbon-containing material to silicon carbide. Also disclosed is an intermediate article that includes a solid structure having free carbon and a solid, in-situ source of silicon monoxide gas. Also disclosed is a composition that includes a polymeric carrier phase and particulate of solid silicon monoxide dispersed in the polymeric carrier phase.