Seal coating

Abstract

A method of forming a coating includes disposing a substrate having a plurality of protrusions on a seal and layering a topcoat over the protrusions. The method of forming a coating also includes creating a wear pattern and converting the topcoat. A turbine section includes a casing, a plurality of blades within the casing, and a substrate deposited on the casing having a plurality of protrusions. The turbine also includes an unconverted topcoat disposed over the plurality of protrusions, the topcoat having segmented portions defining a plurality of faults extending from the protrusions through the topcoat. A method of forming a coating includes creating a channel in the coating during an initial rub event and converting the coating during a high-temperature event. Converting the coating includes preserving the channel created during the initial rub event.

1 . A method of forming a coating comprising:
 disposing a substrate having a plurality of protrusions on a seal;   depositing a topcoat over the protrusions;   creating a wear pattern in the topcoat; and   converting the topcoat.   
     
     
         2 . The method of  claim 1 , wherein the seal is a blade outer air seal. 
     
     
         3 . The method of  claim 1 , wherein the topcoat comprises a thermally insulating ceramic material having a porosity between 5 and 70 volume percent. 
     
     
         4 . The method of  claim 1 , wherein the topcoat comprises segmented portions defining a plurality of faults extending from the plurality of protrusions through the topcoat. 
     
     
         5 . The method of  claim 1 , wherein depositing the topcoat over the plurality of protrusions forms a surface having a plurality of dimples. 
     
     
         6 . The method of  claim 5 , wherein creating a wear pattern comprises rubbing a blade tip against the topcoat during an initial rub event. 
     
     
         7 . The method of  claim 6 , wherein rubbing the blade tip against the topcoat during the initial rub phase forms a channel depth that is less than a depth of the plurality of dimples. 
     
     
         8 . The method of  claim 7 , wherein the wear pattern allows for approximately equal wear to the blade tip and the seal. 
     
     
         9 . The method of  claim 1 , converting the topcoat comprises running an engine to expose the seal to a surface temperature of at least 1950° F. (1066° C.). 
     
     
         10 . A turbine section comprising:
 a casing;   a plurality of blades within the casing;   a substrate deposited on the casing having a plurality of protrusions; and   an unconverted topcoat disposed over the plurality of protrusions, the topcoat having segmented portions defining a plurality of faults extending from the protrusions through the topcoat.   
     
     
         11 . The turbine of  claim 10 , wherein the plurality of protrusions extend from the substrate towards the plurality of blades. 
     
     
         12 . The turbine of  claim 10 , wherein the plurality of protrusions extend from the substrate at a substantially uniform height of at least 0.01 inches (0.0254 centimeters). 
     
     
         13 . The turbine of  claim 10 , wherein the plurality of faults are gaps located between the plurality of protrusions. 
     
     
         14 . The turbine of  claim 10 , wherein the plurality of protrusions forms a grid on the substrate. 
     
     
         15 . The turbine of  claim 14 , wherein the topcoat comprises a plurality of dimples corresponding to a shape of the grid on the substrate. 
     
     
         16 . The turbine of  claim 10 , wherein the unconverted topcoat comprises a thermally insulating ceramic material. 
     
     
         17 . The turbine of  claim 10 , wherein the unconverted topcoat provides a wear pattern configured to allow approximately equal wear to a blade tip a seal. 
     
     
         18 . A method of forming a coating in a turbine, the method comprising:
 applying the coating to a seal in the turbine;   creating a channel in the coating during an initial rub event; and   converting the coating during a high-temperature event, wherein converting the coating comprises preserving the channel created during the initial rub event.   
     
     
         19 . The method of  claim 18 , wherein creating a channel in the coating comprises rapidly accelerating the turbine during a green run, causing rubbing of a blade tip against the coating. 
     
     
         20 . The method of  claim 18 , wherein the high-temperature event comprises running an engine to expose the seal to a surface temperature above 1950° F. (1066° C.).