Turbine Abrasive Blade Tips Oxidation Resistance
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Solution Overview
Problem
High-pressure turbine blade tips and abrasive coatings are prone to oxidation and corrosion due to operational and environmental conditions, leading to decreased cutting performance and engine efficiency over time.
Innovation Solution
A coating system comprising a matrix CBN abrasive coating with a thin film oxidant-resistant coating and a thermal barrier coating applied over the abrasive coating, using materials like Ni, Co, and MCrAlY alloys, with an adhesion layer and a thermal barrier coating that is either thin and dense or thick and porous to maintain cutting ability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin film oxidant-resistant coating is applied over the abrasive coating, then oxidation and corrosion resistance is improved, but the cutting performance may be compromised due to additional layer interference
Solution Approach 1:
The coating system is segmented into multiple functional layers: an abrasive coating layer containing CBN grit particles for cutting, and a separate thin film oxidant-resistant coating layer applied over it. This segmentation allows each layer to perform its specific function independently - the abrasive layer maintains cutting capability while the protective layer prevents oxidation and corrosion, resolving the contradiction between durability and performance.
Solution Approach 2:
The solution employs composite material structure combining the abrasive coating (with metal matrix and CBN grit) and the oxidant-resistant thin film coating. This composite approach creates a multi-functional coating system where the abrasive particles provide cutting action while the protective film matrix provides oxidation and corrosion resistance, allowing both cutting performance and reliability to be maintained simultaneously.
2Temperature
If a thermal barrier coating is applied over the thin film coating, then thermal protection is improved, but the complexity of the coating system increases
Solution Approach 1:
The coating system is segmented into distinct functional layers with the thermal barrier coating applied over the thin film oxidant-resistant coating. This segmentation allows the thermal barrier layer to provide temperature protection while the underlying layers maintain their protective and abrasive functions, managing the complexity through clear functional separation.
Solution Approach 2:
The coating system is designed with multi-functionality where each layer serves multiple purposes: the thin film coating provides both oxidation resistance and serves as a base for the thermal barrier, while the thermal barrier coating provides thermal protection and additional environmental resistance. This multi-functionality reduces overall system complexity by combining multiple protective functions in an integrated layered structure.
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 coating system enhances the oxidation and corrosion resistance of the abrasive tip system, maintaining optimal clearance and cutting performance, thereby improving the durability and efficiency of the turbine blades.
Implementation Method 1
the film is configured to protect said matrix material from oxidation/corrosion by acting as a barrier for oxidant diffusion to the matrix layer and abrasive grit
Implementation Method 2
a thermal barrier coating is applied over the thin film coating
Data Source
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AI summary
An abrasive coating for a substrate of a component in a gas path exposed to a maximum temperature of 1750 degree Fahrenheit (approximately 954°C), comprising a plurality of grit particles (18) adapted to be placed on a top surface (26) of the substrate (14); a matrix material (20) bonded to the top surface (26); the matrix material (20) partially surrounds the grit particles (18), wherein the grit particles (18) extend above the matrix material (20) relative to the top surface (26); a film of oxidant resistant coating (28) applied over the plurality of grit particles (18) and the matrix material (20) and a thermal barrier coating material (30) applied over said film of oxidant resistant coating (28).