A fiber comprises a bulk material comprising one or more materials selected from the group consisting of carbon, silicon, boron, silicon carbide, and boron nitride; and a metal whose affinity for oxygen is greater than the affinity for oxygen of any of the one or more materials. The metal may be selected from the group consisting of beryllium, titanium, hafnium and zirconium. At least a first portion of the metal may be present in un-oxidized form at the entrance to and/or within grain boundaries within the fiber.

A method of improving at least one of the strength, creep resistance, and toughness of a fiber comprises adding to a fiber, initially comprising a bulk material having a first affinity for oxygen, a metal that has a second affinity for oxygen higher than the first affinity. The metal may be selected from the group consisting of beryllium, titanium, hafnium and zirconium.

A gas turbine engine includes a rotatable component and a non-rotatable component. A seal is carried on one of the rotatable component or the non-rotatable component to provide sealing there between. The seal includes a geopolymer seal element.

A circumferential coating material to be applied to a circumferential surface of a honeycomb structure made of ceramics formed by extrusion, the circumferential coating material including a ceramic raw material that forms a circumferential coating layer, wherein the ceramic raw material contains: a ceramic mixture of first ceramic particles having particulate shapes, and second ceramic particles having particulate shapes and an average particle diameter different from an average particle diameter of the first ceramic particles; and a fiber material having an elongated strip-like shape, wherein the ceramic mixture has particle size distribution including at least two local maximum values, and the fiber material has an average fiber length ranging from 30 to 100 m in a longitudinal direction.

A circumferential coating material to be applied to a circumferential surface of a honeycomb structure made of ceramics formed by extrusion, the circumferential coating material including a ceramic raw material that forms a circumferential coating layer, wherein the ceramic raw material contains: a ceramic mixture of first ceramic particles having particulate shapes, and second ceramic particles having particulate shapes and an average particle diameter different from an average particle diameter of the first ceramic particles; and a fiber material having an elongated strip-like shape, wherein the ceramic mixture has particle size distribution including at least two local maximum values, and the fiber material has an average fiber length ranging from 30 to 100 m in a longitudinal direction.

Inorganic coatings that may be used to coat and protect concrete are disclosed. The protective inorganic coatings include a liquid composition portion comprising water, an alkali metal oxide component and a silicate-containing component. The coatings also include a powder composition portion comprising microspheres, metal oxide powder and optional microfibers. When applied to concrete, the coatings provide chemical and physical protection.

Inorganic coatings that may be used to coat and protect concrete are disclosed. The protective inorganic coatings include a liquid composition portion comprising water, an alkali metal oxide component and a silicate-containing component. The coatings also include a powder composition portion comprising microspheres, metal oxide powder and optional microfibers. When applied to concrete, the coatings provide chemical and physical protection.

Inorganic coatings that may be used to coat and protect concrete are disclosed. The protective inorganic coatings include a liquid composition portion comprising water, an alkali metal oxide component and a silicate-containing component. The coatings also include a powder composition portion comprising microspheres, metal oxide powder and optional microfibers. When applied to concrete, the coatings provide chemical and physical protection.

Inorganic coatings that may be used to coat and protect concrete are disclosed. The protective inorganic coatings include a liquid composition portion comprising water, an alkali metal oxide component and a silicate-containing component. The coatings also include a powder composition portion comprising microspheres, metal oxide powder and optional microfibers. When applied to concrete, the coatings provide chemical and physical protection.

A concrete composition having an optimized formulation and suitable for 3-D printing is provided. The composition may include a hydraulic cement composition, aggregate, cement and/or aggregate by-product dust, one or more rheology modifiers, a plasticizer, fibers, and a sufficient amount of water to effect setting of the composition. Optionally the concrete composition may include a setting agent. A method for 3D printing multiple layers of the concrete composition is also provided.

A concrete composition having an optimized formulation and suitable for 3-D printing is provided. The composition may include a hydraulic cement composition, aggregate, cement and/or aggregate by-product dust, one or more rheology modifiers, a plasticizer, fibers, and a sufficient amount of water to effect setting of the composition. Optionally the concrete composition may include a setting agent. A method for 3D printing multiple layers of the concrete composition is also provided.