A seal system includes a ceramic component, a metallic component, a silicon-containing layer, and a barrier layer. The ceramic component has a first surface region that defines a first surface roughness. The metallic component is situated adjacent to the first surface region and has a second surface region facing the first surface region. The silicon-containing layer is on the first surface region of the ceramic component and has a contact surface that defines a second surface roughness which is less than the first surface roughness. The barrier layer is on the metallic component and in contact with the silicon-containing layer and serves to limit interaction between silicon of the silicon-containing layer and the metallic component. The barrier layer includes at least one of alumina or MCrAlY.

A journal support pin to support intermediate gears for use in gas turbine engine comprises a titanium body, and an outer surface outside of the titanium body having a surface hardness that is harder than the body. A gas turbine engine and a method of forming a journal support pin to support intermediate gears for use in gas turbine engine are also disclosed.

A journal support pin to support intermediate gears for use in gas turbine engine comprises a titanium body, and an outer surface outside of the titanium body having a surface hardness that is harder than the body. A gas turbine engine and a method of forming a journal support pin to support intermediate gears for use in gas turbine engine are also disclosed.

A seal system includes a ceramic component, a metallic component, a coating system. The ceramic component has a first surface region that defines a first surface roughness. The metallic component is situated adjacent to the first surface region and has a second surface region facing the first surface region. The coating system includes a silicon-containing layer on the surface region of the ceramic component and barrier layer on the silicon-containing layer. The silicon containing layer has a surface in contact with the barrier layer and the barrier layer has a surface in contact with the metallic component. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The barrier layer serves to limit interaction between silicon of the silicon-containing layer and elements of the metallic component. The barrier layer includes at least one of mullite, zircon, or hafnon.

A seal system includes a ceramic component, a metallic component, a coating system. The ceramic component has a first surface region that defines a first surface roughness. The metallic component is situated adjacent to the first surface region and has a second surface region facing the first surface region. The coating system includes a silicon-containing layer on the surface region of the ceramic component and barrier layer on the silicon-containing layer. The silicon containing layer has a surface in contact with the barrier layer and the barrier layer has a surface in contact with the metallic component. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The barrier layer serves to limit interaction between silicon of the silicon-containing layer and elements of the metallic component. The barrier layer includes at least one of mullite, zircon, or hafnon.

A gas turbine engine includes a compressor section with a compressor rotor shaft assembly including a plurality of compressor rotors longitudinally spaced apart from each other via respective ones of a plurality of shaft sections of a rotor shaft, each compressor rotor of the plurality of compressor rotors having a plurality of rotor vanes extending radially outward therefrom and being circumferentially spaced about the compressor rotor. A stator shroud assembly has a stator shroud casing surrounding the compressor rotor shaft assembly, a compressor flow passage being defined between the compressor rotor shaft assembly and the stator shroud casing. A pressurized air source generates a flow of pressurized air to be provided to the compressor section, and a plurality of pressurized airflow nozzles are connected with the pressurized air source and provide the flow of pressurized air into the compressor flow passage to cause the compressor rotor shaft assembly to rotate.

A gas turbine engine includes a compressor section with a compressor rotor shaft assembly including a plurality of compressor rotors longitudinally spaced apart from each other via respective ones of a plurality of shaft sections of a rotor shaft, each compressor rotor of the plurality of compressor rotors having a plurality of rotor vanes extending radially outward therefrom and being circumferentially spaced about the compressor rotor. A stator shroud assembly has a stator shroud casing surrounding the compressor rotor shaft assembly, a compressor flow passage being defined between the compressor rotor shaft assembly and the stator shroud casing. A pressurized air source generates a flow of pressurized air to be provided to the compressor section, and a plurality of pressurized airflow nozzles are connected with the pressurized air source and provide the flow of pressurized air into the compressor flow passage to cause the compressor rotor shaft assembly to rotate.

A gas turbine engine includes a propulsor and a fan drive turbine. The fan drive turbine drives the propulsor through a geared architecture. The geared architecture includes a sun gear, a ring gear, and intermediate gears supported on journal support pins. The sun gear engages the intermediate gears and the intermediate gears engages the ring gear. The journal support pins include a titanium body and an outer surface outside of the titanium body that has a surface hardness that is harder than the titanium body. The outer surface is provided by a steel sleeve. Oil supply holes extend from a central bore in the titanium body through the steel sleeve. At least one pin extends through the steel sleeve to secure the steel sleeve to the titanium body.

A gas turbine engine includes a propulsor and a fan drive turbine. The fan drive turbine drives the propulsor through a geared architecture. The geared architecture includes a sun gear, a ring gear, and intermediate gears supported on journal support pins. The sun gear engages the intermediate gears and the intermediate gears engages the ring gear. The journal support pins include a titanium body and an outer surface outside of the titanium body that has a surface hardness that is harder than the titanium body. The outer surface is provided by a steel sleeve. Oil supply holes extend from a central bore in the titanium body through the steel sleeve. At least one pin extends through the steel sleeve to secure the steel sleeve to the titanium body.

A gas turbine engine has a compressor section, a combustor, and a turbine section. An associated fluid is to be cooled and an associated fluid is to be heated. A transcritical vapor cycle heats the fluid to be heated, and cools the fluid to be cooled. The transcritical vapor cycle includes a gas cooler in which the fluid to be heated is heated by a refrigerant in the transcritical vapor cycle. An evaporator heat exchanger at which the fluid to be cooled is cooled by the refrigerant in the transcritical vapor cycle. A compressor upstream of the gas cooler compresses the refrigerant to a pressure above a critical point for the refrigerant. An expansion device expands the refrigerant downstream of the gas cooler, with the evaporator heat exchanger being downstream of the expansion device, and such that the refrigerant passing through the gas cooler to heat the fluid to be heated is generally above the critical point.