A blade outer air seal has at least one internal surface and a layer atop the at least one internal surface. The layer has: a matrix comprising at least one of hafnium silicate (HfSiO.sub.4) and zirconium silicate (ZrSiO.sub.4), ytterbium disilicate (Yb.sub.2Si.sub.2O.sub.7); and barium magnesium alumino silicate (BMAS) or other alkaline earth aluminosilicate.

A blade outer air seal has at least one internal surface and a layer atop the at least one internal surface. The layer has: a matrix comprising at least one of hafnium silicate (HfSiO.sub.4) and zirconium silicate (ZrSiO.sub.4), ytterbium disilicate (Yb.sub.2Si.sub.2O.sub.7); and barium magnesium alumino silicate (BMAS) or other alkaline earth aluminosilicate.

Provided herein are compositions, methods, and systems related to aggregates, such as e.g., lightweight aggregates, formed from the reactive vaterite cement compositions.

A blade outer air seal has at least one internal surface and a layer atop the at least one internal surface. The layer has: a matrix comprising at least one of hafnium silicate (HfSiO.sub.4) and zirconium silicate (ZrSiO.sub.4), ytterbium disilicate (Yb.sub.2Si.sub.2O.sub.7); and barium magnesium alumino silicate (BMAS) or other alkaline earth aluminosilicate.

A blade outer air seal has at least one internal surface and a layer atop the at least one internal surface. The layer has: a matrix comprising at least one of hafnium silicate (HfSiO.sub.4) and zirconium silicate (ZrSiO.sub.4), ytterbium disilicate (Yb.sub.2Si.sub.2O.sub.7); and barium magnesium alumino silicate (BMAS) or other alkaline earth aluminosilicate.

A method for coating a substrate includes spraying a combination of powders. The combination of powders includes: Hf.sub.0.5Si.sub.0.5O.sub.2; Zr.sub.0.5Si.sub.0.5O.sub.2; and, optionally, at least one of HfO.sub.2 and ZrO.sub.2. A molar ratio of said Hf.sub.0.5Si.sub.0.5O.sub.2 and HfO.sub.2 combined to said Zr.sub.0.5Si.sub.0.5O.sub.2 and ZrO.sub.2 combined is from 2:1 to 4:1. A molar ratio of said Hf.sub.0.5Si.sub.0.5O.sub.2 to said HfO.sub.2 is at least 1:3.

A method for coating a substrate includes spraying a combination of powders. The combination of powders includes: Hf.sub.0.5Si.sub.0.5O.sub.2; Zr.sub.0.5Si.sub.0.5O.sub.2; and, optionally, at least one of HfO.sub.2 and ZrO.sub.2. A molar ratio of said Hf.sub.0.5Si.sub.0.5O.sub.2 and HfO.sub.2 combined to said Zr.sub.0.5Si.sub.0.5O.sub.2 and ZrO.sub.2 combined is from 2:1 to 4:1. A molar ratio of said Hf.sub.0.5Si.sub.0.5O.sub.2 to said HfO.sub.2 is at least 1:3.

The present invention is directed to a biopolymer cement additive, a biopolymer cement composition containing the additive, the use of the additive for the production of, mortar or concrete and a process for the preparation of concrete or mortar implementing the biopolymer cement additive.

The present invention is directed to a biopolymer cement additive, a biopolymer cement composition containing the additive, the use of the additive for the production of, mortar or concrete and a process for the preparation of concrete or mortar implementing the biopolymer cement additive.

Body made of a ceramic material, the body having as an integral part thereof a surface region reaching from the surface of the body down to a predetermined depth. According to the invention, the surface region is enriched with a magnesium component thereby forming a hydrophilic surface area.