Turbine Coating Apparatus with Segmented Chamber and Cut-Out Plate
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Solution Overview
Problem
Current vapor phase aluminizing processes cannot effectively coat the internal surfaces of turbine engine components without also coating the external surfaces, which reduces thermal fatigue resistance and is inefficient due to the nickel alloy coating apparatus acting as a reservoir for aluminum, leading to external surface coating during subsequent cycles.
Innovation Solution
A coating apparatus with a vessel divided into compartments, using a coating gas generator in one compartment and an inert gas flow in another to prevent external coating deposition, featuring a graphite vessel and a plate with cut-outs for workpieces, allowing inert gas to flow over external surfaces and direct coating gas into internal passageways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vapor phase aluminizing process is used to coat internal surfaces, then oxidation/corrosion protection is achieved, but external surface coating deposition occurs which reduces thermal fatigue resistance
Solution Approach 1:
The coating apparatus is segmented into a first chamber for coating gas generation and a second chamber for workpiece placement, separated by a divider with a plate featuring cut-outs. This spatial segmentation allows coating gas to be directed specifically into internal passages through the cut-outs while preventing external surface exposure to coating material, thus achieving internal protection without compromising external thermal fatigue resistance.
Solution Approach 2:
The plate with cut-outs provides localized coating material delivery only to specific internal passages that require protection. This local quality approach ensures that coating is applied precisely where needed (internal surfaces) while leaving external surfaces untouched, maintaining their thermal fatigue resistance properties.
2Reliability
If standard vapor phase aluminizing is used, then internal surfaces are coated, but coating thickness cannot be controlled to be less than 0.001 inches on external surfaces
Solution Approach 1:
The divided chamber structure with the plate separator creates distinct zones: the first chamber generates coating gas while the second chamber holds workpieces. The plate with cut-outs acts as a precision delivery mechanism, allowing coating material to pass only through controlled openings into internal passages, thereby preventing uncontrolled deposition on external surfaces and achieving thickness control below 0.001 inches.
Solution Approach 2:
The plate with cut-outs serves as an intermediary component between the coating gas source and the workpiece internal passages. It mediates the coating material flow by allowing selective passage only through the cut-outs, preventing direct exposure of external surfaces to coating material and enabling precise thickness control on internal surfaces while keeping external deposition minimal.
3Productivity
If nickel alloy coating apparatus is used, then coating process can be performed, but apparatus acts as aluminum reservoir coating external surfaces during subsequent cycles
Solution Approach 1:
The harmful property of the nickel alloy apparatus acting as an aluminum reservoir is extracted and eliminated by replacing it with an inert graphite-based apparatus. Graphite does not absorb or release aluminum coating material, thereby removing the reservoir effect that caused external surface coating during subsequent cycles, while maintaining the coating process capability through the controlled gas flow system.
Solution Approach 2:
The nickel alloy apparatus is replaced with graphite material that creates an inert environment regarding coating material interaction. Graphite does not chemically interact with or store aluminum coating material, preventing it from acting as a reservoir that would subsequently coat external surfaces. This inert environment maintains productivity while eliminating the harmful reservoir effect.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus minimizes external surface coating deposition to less than 0.001 inches, maintaining thermal fatigue resistance and achieving targeted internal oxidation/corrosion protection for turbine engine components.
Implementation Method 1
a coating gas generator (42) in the second compartment
Implementation Method 2
creating a flow of an inert gas over exterior surfaces of the at least one workpiece
Data Source
Figure 1
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AI summary
A coating apparatus for coating interior surfaces of internal passages of a workpiece, such as a turbine engine component is provided. The coating apparatus comprises a vessel defining an internal space, a plate dividing the internal space into a first chamber and a second chamber, a divider supporting the plate, and the plate having at least one cut-out for receiving a portion of the workpiece-having the internal passages to be coated.