Indium Oxide Co-Stabilized Thermal Barrier Coating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal barrier coatings for high-temperature metallic components, such as those in industrial gas turbines, face challenges in stabilizing the cubic phase of zirconia and resisting corrosion from fuel impurities like sodium, sulfur, and vanadium, leading to premature degradation and reduced lifespan.
Innovation Solution
A corrosion-resistant thermal barrier coating material is developed by blending indium oxide with indate forming oxides, forming a co-stabilized mixture with zirconia or hafnia, and using a combination of air plasma sprayable or electron beam physical vapor deposition processes to create a stable coating that resists chemical attacks and maintains the tetragonal and cubic phases of zirconia or hafnia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scandia stabilized zirconia is used as a thermal barrier coating, then the coating has high resistance to corrosives and effective thermal barrier properties, but the cost becomes extremely expensive making it impractical for widespread use
Solution Approach 1:
The patent changes the chemical composition parameters by substituting scandia with a combination of indium oxide and indate forming oxides (such as lanthanum oxide, cerium oxide, or yttrium oxide). This parameter substitution maintains the stabilizing function while dramatically reducing cost, as indium and the selected indate forming oxides are significantly cheaper than scandia while still providing effective corrosion resistance and thermal barrier properties
Solution Approach 2:
The patent employs cheaper alternative materials (indium oxide combined with indate forming oxides) that can provide comparable performance to expensive scandia stabilized zirconia. This principle allows replacement of high-cost materials with lower-cost alternatives that achieve the same functional objectives, making thermal barrier coatings economically viable for widespread industrial application
2Ease of manufacture
If indium stabilized zirconia is used as a thermal barrier coating, then the coating can be cost effective, but the indium is so volatile that it boils off during plasma spraying or electron beam physical deposition and does not remain in the thermal barrier coating
Solution Approach 1:
The patent merges indium oxide with indate forming oxides (such as lanthanum oxide, cerium oxide, or yttrium oxide) to create a composite stabilizing system. This combination allows the indium to be present in lower concentrations that do not cause excessive volatility, while the indate forming oxides provide structural stability and prevent indium loss during plasma spraying or electron beam physical deposition processes
Solution Approach 2:
The indate forming oxides act as intermediary substances that stabilize the zirconia structure and prevent indium volatilization. These intermediaries form a stable matrix that retains the indium within the coating structure during high-temperature deposition processes, ensuring the indium remains in the final thermal barrier coating to provide corrosion resistance
3Ease of manufacture
If conventional thermal barrier coating methods are used, then the coating can be applied, but impurities in fuels such as sodium, sulfur, phosphorus, and vanadium corrode the coating causing spalling and reducing component lifetime
Solution Approach 1:
The patent uses a composite material system consisting of indium oxide combined with indate forming oxides (such as lanthanum oxide, cerium oxide, or yttrium oxide) stabilized zirconia. This composite composition provides enhanced corrosion resistance against fuel impurities (sodium, sulfur, phosphorus, and vanadium) compared to conventional single-stabilizer coatings, while maintaining the ability to be applied through standard plasma spraying or electron beam physical deposition processes
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 solution effectively prevents the transformation of zirconia or hafnia to the monoclinic phase, thereby preventing cracking, spalling, and chemical attack, extending the lifespan and efficiency of the thermal barrier coating and the underlying metallic components.
Implementation Method 1
blending indium oxide with indate forming oxides, forming a co-stabilized mixture with zirconia or hafnia, and using a combination of air plasma sprayable or electron beam physical vapor deposition processes to create a stable coating that resists chemical attacks and maintains the tetragonal and cubic phases of zirconia or hafnia
Implementation Method 2
air plasma sprayable processes
Implementation Method 3
electron beam physical vapor deposition processes
Implementation Method 4
a corrosion-resistant thermal barrier coating material is developed by blending indium oxide with indate forming oxides, forming a co-stabilized mixture with zirconia or hafnia
Data Source
AI summary
According to one exemplary embodiment, a method for forming a corrosion resistant thermal barrier coating material includes steps of blending indium oxide with at least one hydrate forming oxide to form a mechanical mixture, heating the mechanical mixture to a sufficiently high temperature to form an indate precursor, and blending the indate precursor with at least one non-hydrate forming oxide to form a co-stabilized mixture. In one embodiment, the co-stabilized mixture can be changed into an APS powder by using a powder forming method. In another embodiment, the co-stabilized mixture can be formed into a desired shape and heated to form an EB-PVD ingot.