Air turbine starter
An air turbine starter having a housing that includes an inlet and an outlet to define an air flow path from the inlet to the outlet. A stator includes a plurality of circumferentially spaced vanes extending into the air flow path and defined a stator core. A coating surrounds one or more portions of the housing, defining the housing core, or the stator, defining the stator core. The housing core or the stator core includes a first material having a first hardness and the coating comprises a second material having a second hardness.
1 . An air turbine starter comprising:
a housing having an inlet and an outlet to define an air flow path from the inlet to the outlet;
a stator rotationally stationary relative to the housing and having a plurality of circumferentially spaced vanes extending into the air flow path; and
a coating applied to one or more portions of both the housing and the stator, wherein the coating includes one or more portions that confront the air flow path and one or more portions that do not confront the air flow path;
wherein the housing or the stator comprise a first material having a first hardness, and wherein the coating comprises a second material having a second hardness that is greater than the first hardness; and
wherein the coating includes a coating thickness, and wherein the coating applied to the housing and the stator that confronts the air flow path along among both the housing and the stator is thicker than the coating that does not confront the air flow path.
2 . The air turbine starter of claim 1 , further comprising a thermal barrier coating located between the coating and one of the housing or the stator.
3 . The air turbine starter of claim 1 , wherein the first material comprises aluminum and the second material comprises nickel cobalt phosphate (NiCoP).
4 . The air turbine starter of claim 1 , wherein the coating comprises multiple layers.
5 . The air turbine starter of claim 1 , wherein the first material has a first thermal conductivity and the second material has a second thermal conductivity, which is lesser than the first thermal conductivity.
6 . The air turbine starter of claim 1 , wherein the first material is electrically conductive.
7 . The air turbine starter of claim 6 , wherein the housing or the stator are electrically conductive and the coating is electroformed to surround the housing or the stator.
8 . The air turbine starter of claim 1 , wherein the housing includes an inlet housing that defines the inlet, wherein the coating surrounds at least a portion of the inlet housing.
9 . The air turbine starter of claim 1 , wherein the housing has a housing thickness, the stator has a stator thickness, and wherein the coating thickness is in a range of 5% to 200% of the housing thickness or stator thickness.
10 . The air turbine starter of claim 1 , wherein the coating extends over at least the plurality of circumferentially spaced vanes that extend into the air flow path.
11 . The air turbine starter of claim 10 , wherein each vane of the plurality of circumferentially spaced vanes extends from a leading edge to a trailing edge.
12 . The air turbine starter of claim 11 , wherein the coating thickness at the leading edge is greater than the coating thickness at the trailing edge.
13 . The air turbine starter of claim 12 , wherein the stator includes a nose from which the plurality of circumferentially spaced vanes extend into the air flow path.
14 . The air turbine starter of claim 13 , wherein the coating thickness measured at an axially forward surface of the nose is greater than the coating thickness measured at an axially aft surface of the nose.
15 . The air turbine starter of claim 1 , wherein the housing includes a housing core and the stator includes a stator core, and wherein the housing core or the stator core is a sacrificial mandrel.
16 . The air turbine starter of claim 15 , wherein the first material comprises magnesium, aluminum, zinc, one or more polymers, carbon, or any combination therein and the second material comprises nickel cobalt phosphate (NiCoP).
17 . The air turbine starter of claim 15 , wherein removal of the sacrificial mandrel forms a hollow housing core or a hollow stator core, wherein support structures span the hollow housing core or the hollow stator core.
18 . The air turbine starter of claim 17 , wherein the hollow housing core has a housing thickness, the hollow stator core has a stator thickness, and wherein the coating thickness is in a range of greater than 0% and less than or equal to 600% of the housing thickness or the stator thickness.