Water-Soluble Paste for Cooling Hole Masking in Thermal Barrier Coating
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Solution Overview
Problem
The incorporation of thermal barrier coatings (TBC) and cooling holes in engine components is challenging due to the difficulty in forming holes after TBC application, as lasers struggle to penetrate ceramic materials, leading to potential blockage and overheating issues.
Innovation Solution
A method involving a paste with a high temperature-resistant filler material, inorganic binder, and polyhydroxy compound, applied to mask holes before coating, which can be easily removed with water, preventing blockage and ensuring the integrity of cooling holes during high-temperature operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling holes are formed prior to TBC application, then cooling holes can be created in the component, but the holes become covered and partially obstructed when TBC is applied
Solution Approach 1:
The patent applies a release agent to the cooling holes before TBC application. This preliminary action prevents TBC material from adhering to the hole surfaces, ensuring holes remain open and functional after coating is applied.
Solution Approach 2:
The release agent acts as an intermediary substance between the cooling holes and TBC material. It creates a barrier that prevents direct adhesion of TBC to the hole surfaces, allowing TBC to be applied while maintaining hole openness.
2Reliability
If lasers are used to form cooling holes after TBC application, then TBC protection is maintained, but lasers cannot effectively penetrate ceramic material to form holes
Solution Approach 1:
The patent forms cooling holes in the substrate before applying TBC coating. This preliminary hole formation avoids the need for post-coating laser drilling through ceramic material, making the manufacturing process more feasible and effective.
3Manufacturing precision
If complete removal of TBC material from holes is attempted, then hole blockage may be prevented, but the process becomes very time-consuming and ineffective
Solution Approach 1:
The release agent is applied before TBC coating to prevent TBC material from adhering to the cooling holes in the first place. This preliminary protective action eliminates the need for time-consuming post-coating removal operations.
Solution Approach 2:
Instead of trying to remove adhered TBC material (a harmful situation), the patent uses a release agent to prevent adhesion altogether, converting the potential harm of TBC blockage into the benefit of easy hole maintenance.
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 method effectively prevents hole blockage during coating, maintains the structural integrity of cooling holes, and allows for easy removal of the paste, ensuring efficient heat management and engine performance.
Implementation Method 1
The paste includes from about 40 weight percent to about 80 weight percent of a high temperature resistant filler material
Implementation Method 2
removing the paste including contacting the paste with water
Data Source
AI summary
A method includes masking at least one hole of an article with a paste, wherein the hole opens onto a surface of the article, applying a coating to the surface of the article, and removing the paste including contacting the paste with water, leaving at least one open hole in the surface of the coated article. The paste includes about 40-80 wt % of a filler material, about 0.5-20 wt % of an inorganic binder, about 0.5-15 wt % of a polyhydroxy compound and about 5-25 wt % of water. The filler material includes a first material which includes alkali metal doped alumina, zirconium oxide, titanium oxide, silicon dioxide, or a combination thereof and a second material which includes a silicate. A weight ratio between the first and second materials is in a range of about 1-10.