Geometrically segmented abradable ceramic thermal barrier coating with improved spallation resistance
A turbine article includes a substrate with a geometric surface having a multiple of divots recessed into the substrate, and a ceramic topcoat disposed over the geometric surface, the topcoat including at least a first layer having a first hardness and a second layer having a second hardness, the first hardness different than the second hardness.
1. A process for manufacturing a geometrically segmented abradable coating on a turbine engine component having a geometric surface comprising a multiple of raised substrate features and a multiple of divots forming coplanar surfaces, the process comprising the steps of:
depositing a first layer of a ceramic topcoat on a top surface of a multiple of raised substrate features of the geometric surface and within a bottom of each of a multiple of divots of the geometric surface, the first layer having a first hardness, the top surface of the multiple of raised substrate features and the bottom of each of the multiple of divots forming coplanar surfaces that are generally perpendicular to a spray stream for depositing the geometrically segmented abradable coating;
depositing a second layer of the ceramic topcoat on the first layer, the second layer having a second hardness, the first hardness higher than the second hardness; and
depositing a third layer on the second layer, the third layer having a hardness about equivalent to the first hardness, the third layer aligned above each of the multiple of divots corresponding with the first layer aligned above the top surface of the multiple of raised substrate features of the geometric surface.
2. The process of claim 1 , further comprising:
depositing a fourth layer on the third layer, the fourth layer having a hardness about equivalent to the second hardness;
depositing a fifth layer on the fourth layer, the fifth layer having a hardness about equivalent to the first hardness; and
machining away the layers aligned above the multiple of raised substrate features of the geometric surface such that the fifth layer aligned above the multiple of divots corresponds with the third layer aligned above the multiple of raised substrate features of the geometric surface.
3. The process of claim 2 , wherein machining the ceramic topcoat comprises removing raised material over the top surface of a multiple of raised substrate features.
4. The process of claim 3 , further comprising redepositing at least a portion of the fifth layer.
5. The process of claim 1 , wherein the third layer thickness spans the top surface of the multiple of raised substrate features of the geometric surface.
6. The process of claim 1 , wherein a divot depth of the geometric surface is 10-50 mils, the first layer thickness spans from 0-15% of the divot depth (with 0% being the bottom of the divot) and the third layer thickness spans 90-115% the divot depth.
7. A process for manufacturing a geometrically segmented abradable coating on a turbine engine component having a geometric surface comprising a multiple of raised substrate features and a multiple of divots forming coplanar surfaces, the process comprising the steps of:
depositing a first layer of a ceramic topcoat on a top surface of a multiple of raised substrate features of the geometric surface and within a bottom of each of a multiple of divots of the geometric surface, the first layer having a first hardness, the top surface of the multiple of raised substrate features and the bottom of each of the multiple of divots forming coplanar surfaces that are generally perpendicular to a spray stream for depositing the geometrically segmented abradable coating;
depositing a second layer of the ceramic topcoat on the first layer, the second layer having a second hardness, the first hardness higher than the second hardness; and
depositing a third layer on the second layer, the third layer having a hardness about equivalent to the first hardness, the third layer aligned above each of the multiple of divots corresponding with the first layer aligned above the top surface of the multiple of raised substrate features of the geometric surface, wherein a divot depth of the geometric surface is 10-50 mils, the first layer thickness spans from 0-15% of the divot depth (with 0% being the bottom of the divot) and the third layer thickness spans 90-115% the divot depth;
depositing a fourth layer on the third layer, the fourth layer having a hardness about equivalent to the second hardness;
depositing a fifth layer on the fourth layer, the fifth layer having a hardness about equivalent to the first hardness; and
machining away the layers aligned above the multiple of raised substrate features of the geometric surface such that the fifth layer aligned above each of the multiple of divots corresponds with the third layer aligned above the multiple of raised substrate features of the geometric surface.
8. The process of claim 7 , wherein the fifth layer is about 5-20 mils thick prior to being machined, then 3-10 mils thick after being machined.