A thermally-insulating composite material with co-shrinkage in the form of an insulating material formed by the inclusion of microballoons in a matrix material such that the microballoons and the matrix material exhibit co-shrinkage upon processing. The thermally-insulating composite material can be formed by a variety of microballoon-matrix material combinations such as polymer microballoons in a preceramic matrix material. The matrix materials generally contain fine rigid fillers.

Provided herein are methods for making a freeze-cast material having a internal structure, the methods comprising steps of: determining the internal structure of the material, the internal structure having a plurality of pores, wherein: each of the plurality of pores has directionality; and the step of determining comprises: selecting a temperature gradient and a freezing front velocity to obtain the determined internal structure based on the selected temperature gradient and the selected freezing front velocity; directionally freezing a liquid formulation to form a frozen solid, the step of directionally freezing comprising: controlling the temperature gradient and the freezing front velocity to match the selected temperature gradient and the selected freezing front velocity during directionally freezing; wherein the liquid formulation comprises at least one solvent and at least one dispersed species; and subliming the at least one solvent out of the frozen solid to form the material.

Scalable 3D-printing of ceramics includes dispensing a preceramic polymer at the tip of a moving nozzle into a gel that can reversibly switch between fluid and solid states, and subsequently thermally cross-linking the entire printed part “at-once” while still inside the same gel. The solid gel, including mineral oil and silica nanoparticles, converts to fluid at the tip of the moving nozzle, allows the polymer solution to be dispensed, and quickly returns to a solid state to maintain the geometry of the printed polymer both during printing and the subsequent high temperature (160° C.) cross-linking. The cross-linked part is retrieved from the gel and converted to ceramic by high temperature pyrolysis. This scalable process opens new opportunities for low-cost, high-speed production of complex 3-dimensional ceramic parts, and will be widely used for high temperature and corrosive environment applications, including electronics and sensors, microelectromechanical systems, energy, and structural applications.

Solid or liquid N—H free, C-free, and Si-rich perhydropolysilazane compositions comprising units having the following formula [—N(SiH.sub.3).sub.x(SiH.sub.2—).sub.y], wherein x=0, 1, or 2 and y=0, 1, or 2 when x+y=2; and x=0, 1 or 2 and y=1, 2, or 3 when x+y=3 are disclosed. Also disclosed are synthesis methods and applications for the same.

Solid or liquid N—H free, C-free, and Si-rich perhydropolysilazane compositions comprising units having the following formula [—N(SiH.sub.3).sub.x(SiH.sub.2—).sub.y], wherein x=0, 1, or 2 and y=0, 1, or 2 when x+y=2; and x=0, 1 or 2 and y=1, 2, or 3 when x+y=3 are disclosed. Also disclosed are synthesis methods and applications for the same.

A method of chemical vapor infiltration or deposition includes forming silicon carbide in pores of a porous substrate or on a surface of a substrate, the substrate being placed in a reaction enclosure, the silicon carbide being formed from a gas phase introduced into the reaction enclosure, the gas phase including a reagent compound that is a precursor of silicon carbide and that has the following formula ##STR00001##
in which n is an integer equal to 0 or 1; m is an integer lying in the range 1 to 3; p is an integer lying in the range 0 to 2 with m+p=3; and R designates —H or —CH.sub.3; a ratio C/Si between the number of carbon atoms and the number of silicon atoms in the introduced gas phase lying in the range 2 to 3.

A method of chemical vapor infiltration or deposition includes forming silicon carbide in pores of a porous substrate or on a surface of a substrate, the substrate being placed in a reaction enclosure, the silicon carbide being formed from a gas phase introduced into the reaction enclosure, the gas phase including a reagent compound that is a precursor of silicon carbide and that has the following formula ##STR00001##
in which n is an integer equal to 0 or 1; m is an integer lying in the range 1 to 3; p is an integer lying in the range 0 to 2 with m+p=3; and R designates —H or —CH.sub.3; a ratio C/Si between the number of carbon atoms and the number of silicon atoms in the introduced gas phase lying in the range 2 to 3.

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.

Methods and ceramic matrix composite articles formed thereby, as well as systems for making such ceramic matrix composite articles and carrying out such methods are disclosed herein. The methods include preparing a ceramic matrix composite by steps including (a) providing reinforcing fiber, such as carbon fiber, for impregnation; (b) heat treating the reinforcing fiber; (c) impregnating the heat treated reinforcing fiber with a composition comprising a ceramic forming polymer to form a fiber reinforced, ceramic forming polymer pre-preg; and (d) heat molding the fiber reinforced, ceramic forming polymer pre-preg to form a molded ceramic matrix composite article.

A gas turbine engine component includes a gas turbine engine component body formed of a ceramic matrix composite material having at least one fastener integrally formed with the gas turbine engine component body as a single-piece structure. The gas turbine engine component body initially comprises a rigidized preform structure formed from a polymer based material. The at least one fastener connects the gas turbine engine component body to an engine support structure.