A method for preparing a carbon/boron carbide composite material includes the following steps (A) providing a carbon compound, a carbon fiber, a boron compound and a binder to perform a pretreatment mixing procedure to form a precursor; (B) putting the precursor into a spray granulator for performing a granulation process and mixing the precursor to form an injection material with a uniform composition; (C) feeding the injection material into an injection molding machine for performing a compression molding process, thereby forming a carbon compound/boron compound green body; and (D) subjecting the carbon compound/boron compound green body to a two-stage heat treatment process to obtain the carbon/boron carbide composite material.

A material useful as a proppant comprises a core chemically reacted in situ from coal dust and a polymer derived ceramic material, such that at least a portion of the coal dust is chemically converted to a ceramic, nanoparticles, graphene, nanofibers or combinations of any of these.

A crystalline silicon carbide fiber containing silicon carbide and boron nitride, the crystalline silicon carbide fiber having a content of Si of 64% to 72% by weight, a content of C of 28% to 35% by weight, and a content of B of 0.1% to 3.0% by weight, and including, at a surface portion, a composition gradient layer in which a content of silicon carbide increases while a content of boron nitride decreases toward a depth direction.

Disclosed is a modified preceramic polymer having a polymer backbone consisting of silicon or a combination of silicon and carbon; and a pendant modifier bonded to the backbone wherein the modifier includes silicon, boron, aluminum, a transition metal, a refractory metal, or a combination thereof. The modified preceramic polymer can be used to form a ceramic matrix composite.

This disclosure enables direct 3D printing of preceramic polymers, which can be converted to fully dense ceramics. Some variations provide a preceramic resin formulation comprising a molecule with two or more CX double bonds or CX triple bonds, wherein X is selected from C, S, N, or O, and wherein the molecule further comprises at least one non-carbon atom selected from Si, B, Al, Ti, Zn, P, Ge, S, N, or O; a photoinitiator; a free-radical inhibitor; and a 3D-printing resolution agent. The disclosed preceramic resin formulations can be 3D-printed using stereolithography into objects with complex shape. The polymeric objects may be directly converted to fully dense ceramics with properties that approach the theoretical maximum strength of the base materials. Low-cost structures are obtained that are lightweight, strong, and stiff, but stable in the presence of a high-temperature oxidizing environment.

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.

A process for depositing a coating on short fibres of carbon or silicon carbide from a coating precursor, the short fibres having a length of between 50 m and 5 mm, the process including at least heating the short fibres by placing a mixture including the fibres and a liquid phase of the coating precursor in a microwave field so as to bring the surface of the fibres to a temperature allowing the coating on the fibres from the coating precursor to be formed by calefaction.

Pre-ceramic particle solutions can prepared by a Coordinated-PDC process, a Direct-PDC process or a Coordinated-Direct-PDC process. The pre-ceramic particle solution includes a polymer selected from the group consisting of (i) an organic polymer including a metal or metalloid cation, (ii) a first organometallic polymer and (iii) a second organometallic polymer including a metal or metalloid cation different from a metal in the second organometallic polymer, a plurality of particles selected from the group consisting of (a) a ceramic fuel particle and (b) a moderator particle, a dispersant, and a polymerization initiator. The pre-ceramic particle solution can be supplied to an additive manufacturing process, such as digital light projection, and made into a structure (which is pre-ceramic particle green body) that can then be debinded to form a polymer-derived ceramic sintered body. In some embodiments, the polymer-derived ceramic sintered body is a component or structure for fission reactors.

This disclosure enables direct 3D printing of preceramic polymers, which can be converted to fully dense ceramics. Some variations provide a preceramic resin formulation comprising a molecule with two or more CX double bonds or CX triple bonds, wherein X is selected from C, S, N, or O, and wherein the molecule further comprises at least one non-carbon atom selected from Si, B, Al, Ti, Zn, P, Ge, S, N, or O; a photoinitiator; a free-radical inhibitor; and a 3D-printing resolution agent. The disclosed preceramic resin formulations can be 3D-printed using stereolithography into objects with complex shape. The polymeric objects may be directly converted to fully dense ceramics with properties that approach the theoretical maximum strength of the base materials. Low-cost structures are obtained that are lightweight, strong, and stiff, but stable in the presence of a high-temperature oxidizing environment.

This disclosure enables direct 3D printing of preceramic polymers, which can be converted to fully dense ceramics. Some variations provide a preceramic resin formulation comprising a molecule with two or more CX double bonds or CX triple bonds, wherein X is selected from C, S, N, or O, and wherein the molecule further comprises at least one non-carbon atom selected from Si, B, Al, Ti, Zn, P, Ge, S, N, or O; a photoinitiator; a free-radical inhibitor; and a 3D-printing resolution agent. The disclosed preceramic resin formulations can be 3D-printed using stereolithography into objects with complex shape. The polymeric objects may be directly converted to fully dense ceramics with properties that approach the theoretical maximum strength of the base materials. Low-cost structures are obtained that are lightweight, strong, and stiff, but stable in the presence of a high-temperature oxidizing environment.