A gas turbine engine includes an inlet duct, a compressor section, a combustor section, and a turbine section connected to drive the compressor section. The compressor section includes circumferentially-spaced blades having abrasive blade tips. A seal is disposed radially outwards of the blades. The seal includes a substrate that has a substrate hardness, an abradable layer that has an abradable layer hardness, and a hard interlayer between the substrate and the abradable layer. The hard interlayer has an interlayer hardness that is higher than the abradable layer hardness and higher than the substrate hardness.

An air bearing according to an example of the present disclosure includes a stationary member and a shaft with a flange configured to rotate with respect to the stationary member, and at least one of the flange and the shaft have a tungsten-carbide-based coating. An alternative air bearing and a method of making an air bearing are also disclosed.

An impeller blade that includes an impeller blade body constructed of a first material. The impeller blade body defines a leading edge that faces a direction of rotation. A second material couples to the leading edge. The second material is a more erosion resistant material than the first material. The second material extends over the leading edge a distance to absorb high angle impacts of droplets and/or particulate. A third material couples to at least a portion of the impeller blade body.

A seal for a gas turbine engine including an interlayer between a substrate and an abradable layer, the interlayer containing abrasive particles of which at least some abrasive particles protrude out of an interface that abuts the abradable layer.

Coating systems for a cooled turbine blade tip, such as a metal turbine blade tip, are provided. The coating system includes an abrasive layer overlying the surface of the turbine blade tip. One or more buffer layers may additionally be disposed between an outer surface of the blade tip and the abrasive layer. The coated blade tip can be used with a ceramic matrix composite (CMC) shroud coated with an environmental barrier coating (EBC) to provide improved cooling to the tip so as to lengthen oxidation time of the abrasive layer and reduce blade tip wear. Methods are also provided for forming the cooled blade tip and applying the coating system onto the cooled turbine blade tip.

A first stage turbine nozzle includes a first stage hub portion extending axially along a central axis, a first stage disk portion attached to the first stage hub portion and centered on the central axis, and a plurality of first stage vanes positioned radially around and attached to the first stage disk portion. Each vane extends a vane height H away from the first stage disk portion and each vane has a first end positioned at a diameter D away from the central axis. The first stage turbine nozzle also includes a plurality of first stage throats defined between radially adjacent first stage vanes. Each first stage throat has a throat width W between radially adjacent first stage vanes. The first stage turbine nozzle also includes a coating on a sidewall of each first stage vane.

A second stage turbine nozzle includes a second stage disk portion having a central axis, and a plurality of second stage vanes positioned radially around and attached to the second stage disk portion. Each second stage vane extends a vane height H away from the second stage disk portion and each second stage vane has a first end positioned at a diameter D away from the central axis. The second stage turbine nozzle also includes a plurality of second stage throats defined between radially adjacent second stage vanes. Each second stage throat has a throat width W between radially adjacent second stage vanes. The second stage turbine nozzle also includes a coating on a sidewall of each second stage vane, wherein a surface roughness of the sidewall is between 125 microinches Ra and 200 microinches Ra.

A gas turbine engine includes an inlet duct, a compressor section, a combustor section, and a turbine section connected to drive the compressor section. The compressor section includes circumferentially-spaced blades having abrasive blade tips. A seal is disposed radially outwards of the blades. The seal includes a substrate that has a substrate hardness, an abradable layer that has an abradable layer hardness, and a hard interlayer between the substrate and the abradable layer. The hard interlayer has an interlayer hardness that is higher than the abradable layer hardness and higher than the substrate hardness.

A heterogeneous composition is disclosed, including an alloy mixture and a ceramic additive. The alloy mixture includes a first alloy having a first melting point of at least a first threshold temperature, and a second alloy having a second melting point of less than a second threshold temperature. The second threshold temperature is lower than the first threshold temperature. The first alloy, the second alloy, and the ceramic additive are intermixed with one another as distinct phases. An article is disclosed including a first portion including a material composition, and a second portion including the heterogeneous composition. A method for forming the article is disclosing, including applying the second portion to the first portion.

Impellers made of composite materials with flow path cavities covered by an erosion resistant coating are manufactured by covering removable molds having shapes corresponding to a negative geometry of the flow path cavities, with the erosion resistant coating using plating or thermal spraying. After shaping and curing a composite material around the molds covered with the erosion resistant coating, the molds are removed, while the erosion resistant coating remains on the composite impeller.