Ultra-lightweight aerogels and methods for fabricating such aerogels from ammonia borane and a support structure, where the support structure is either two-dimensional nanostructures, or hydrocarbon polymer colloids. The components are mixed, then annealed. The properties of the disclosed aerogels can be tuned by controlling the ratio between the support structure and the ammonia borane, or by infiltrating the aerogels with additives.

Ultra-lightweight aerogels and methods for fabricating such aerogels from ammonia borane and a support structure, where the support structure is either two-dimensional nanostructures, or hydrocarbon polymer colloids. The components are mixed, then annealed. The properties of the disclosed aerogels can be tuned by controlling the ratio between the support structure and the ammonia borane, or by infiltrating the aerogels with additives.

Ultra-lightweight aerogels and methods for fabricating such aerogels from ammonia borane and a support structure, where the support structure is either two-dimensional nanostructures, or hydrocarbon polymer colloids. The components are mixed, then annealed. The properties of the disclosed aerogels can be tuned by controlling the ratio between the support structure and the ammonia borane, or by infiltrating the aerogels with additives.

A turbine engine has: a first member (22) having a surface bearing an abradable coating, the abradable coating (36) being at least 90% by weight ceramic; and a second member (24) having a surface bearing an abrasive coating. The abrasive coating (56) has a metallic matrix (64) and a ceramic oxide abrasive (66) held by the metallic matrix, the first member and second member mounted for relative rotation with the abrasive coating facing or contacting the abradable coating. At least 50% by weight of the ceramic abrasive has a melting point at least 400K higher than a melting point of at least 20% by weight of the ceramic of the abradable coating.

A turbine engine has: a first member (22) having a surface bearing an abradable coating, the abradable coating (36) being at least 90% by weight ceramic; and a second member (24) having a surface bearing an abrasive coating. The abrasive coating (56) has a metallic matrix (64) and a ceramic oxide abrasive (66) held by the metallic matrix, the first member and second member mounted for relative rotation with the abrasive coating facing or contacting the abradable coating. At least 50% by weight of the ceramic abrasive has a melting point at least 400K higher than a melting point of at least 20% by weight of the ceramic of the abradable coating.

A method for producing an aggregated boron nitride particle, containing: a nitriding step of nitriding a particle containing boron carbide to obtain a particle containing boron carbonitride; and a decarburizing step of decarburizing the particle containing boron carbonitride to obtain an aggregated boron nitride particle, wherein, in the nitriding step, nitriding is performed so that boron carbide remains inside the particle containing boron carbonitride, and wherein, in the decarburizing step, the boron carbide remaining inside the particle containing boron carbonitride is removed.

A fiber comprises a bulk material comprising: one or more of carbon, silicon, boron, silicon carbide, and boron nitride; and a metal or metal alloy whose affinity for oxygen is greater than that of the bulk material. At least a first portion of the metal or metal alloy is present at the entrance to grain boundaries at the surface of the fiber and within the fiber to a depth of at least 1 micron from the fiber surface. A method of improving a fiber comprises heating a fiber in an inert atmosphere to 900-1300 C for sufficient time to allow at least some of a metal or metal alloy, placed on the fiber, to diffuse and/or flow into and along grain boundaries to a depth of at least 1 micron. The metal or metal alloy has a greater affinity for oxygen than that of the fiber bulk material.

A fiber comprises a bulk material comprising: one or more of carbon, silicon, boron, silicon carbide, and boron nitride; and a metal or metal alloy whose affinity for oxygen is greater than that of the bulk material. At least a first portion of the metal or metal alloy is present at the entrance to grain boundaries at the surface of the fiber and within the fiber to a depth of at least 1 micron from the fiber surface. A method of improving a fiber comprises heating a fiber in an inert atmosphere to 900-1300 C for sufficient time to allow at least some of a metal or metal alloy, placed on the fiber, to diffuse and/or flow into and along grain boundaries to a depth of at least 1 micron. The metal or metal alloy has a greater affinity for oxygen than that of the fiber bulk material.

The present invention relates to a suspension comprising 50-95% by weight of the total suspension (w/w) of at least one metallic material and/or ceramic material and/or polymeric material and/or solid carbon containing material; and at least 5% by weight of the total suspension of one or more fatty acids or derivatives thereof. In addition, the invention relates to uses of such suspension in 3D printing processes.

The present invention relates to a suspension comprising 50-95% by weight of the total suspension (w/w) of at least one metallic material and/or ceramic material and/or polymeric material and/or solid carbon containing material; and at least 5% by weight of the total suspension of one or more fatty acids or derivatives thereof. In addition, the invention relates to uses of such suspension in 3D printing processes.