Slotted Ceramic Thermal Barrier Coating for CMAS Resistance
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Solution Overview
Problem
Ceramic thermal barrier coatings in gas turbine engines are vulnerable to damage from environmental contaminants like CMAS, which infiltrate and reduce the coating's strain tolerance, leading to premature failure and increased maintenance costs due to spallation and loss of thermal protection.
Innovation Solution
A slotted ceramic coating with a reactive phase coating is applied, where the ceramic coating has localized slots to prevent CMAS infiltration and the reactive phase coating reacts with environmental contaminants to form a stable barrier, enhancing CMAS resistance and heat transfer performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional ceramic thermal barrier coating is applied to protect turbine components from high temperatures, then thermal protection is provided, but the coating becomes vulnerable to CMAS infiltration and spallation
Solution Approach 1:
The ceramic coating is divided into segmented sections by slots, creating isolated zones that prevent continuous CMAS infiltration paths. The slots act as barriers that segment the coating structure, stopping molten CMAS from penetrating through the entire coating thickness and reaching the substrate.
Solution Approach 2:
A reactive phase coating is applied over the slotted ceramic coating to serve as an intermediary barrier. This reactive phase chemically reacts with incoming CMAS to form a stable protective layer, preventing direct contact and damage between CMAS and the underlying thermal barrier coating.
2Duration of action of stationary object
If the ceramic coating structure is modified to improve CMAS resistance, then coating life is extended, but the coating complexity increases
Solution Approach 1:
The coating is segmented into discrete zones by slots, creating a modular structure that simplifies the analysis of CMAS interaction. Each segmented section can be independently evaluated for its resistance to infiltration, and the slots themselves serve as simple geometric features rather than complex structures.
Solution Approach 2:
The coating system combines two distinct material phases: the inert ceramic thermal barrier coating and the reactive phase coating. This composite structure leverages the thermal protection properties of the ceramic while adding the chemical reactivity of the second phase to neutralize CMAS, creating a functionally optimized system.
3Object-affected harmful factors
If slots are introduced into the ceramic coating to prevent CMAS infiltration, then CMAS resistance is improved, but the coating's strain tolerance may be affected
Solution Approach 1:
The slots segment the ceramic coating into isolated sections, which can independently accommodate thermal expansion and strain. This segmentation prevents continuous crack propagation through the coating, as cracks are stopped at the slot boundaries, thereby maintaining overall coating integrity and strain tolerance despite the presence of slots.
Solution Approach 2:
The reactive phase coating serves as an intermediary that protects the ceramic coating from direct CMAS attack. By chemically reacting with CMAS to form a stable barrier layer, it prevents the harmful effects of infiltration while allowing the underlying ceramic coating to maintain its original strain tolerance properties without modification.
4Object-affected harmful factors
If a reactive phase coating is applied over the ceramic coating, then environmental contaminant resistance is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The slots are cut into the ceramic coating before applying the reactive phase coating. This preliminary action allows the reactive phase to be applied as a simple top layer without requiring complex simultaneous patterning or alignment processes. The slots are pre-formed geometric features that guide the subsequent coating application.
Solution Approach 2:
The manufacturing process creates a composite structure by sequentially applying two different coating materials: first the ceramic thermal barrier coating, then the reactive phase coating. This sequential application using standard coating techniques maintains manufacturing simplicity while achieving enhanced environmental contaminant resistance through material composition rather than process complexity.
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 slotted ceramic coating with a reactive phase coating significantly extends the life of thermal barrier coatings by preventing CMAS infiltration and spallation, maintaining thermal protection and reducing maintenance costs by enhancing strain tolerance and environmental resistance.
Implementation Method 1
the reactive phase coating reacts with environmental contaminants to form a stable barrier
Implementation Method 2
the ceramic coating has localized slots to prevent CMAS infiltration
Implementation Method 3
a metal substrate is coated with a TBC ceramic insulating material in order to reduce the service temperature of the underlying metallic segments
Data Source
AI summary
A coated component including a slotted ceramic coating with a reactive phase coating disposed thereon for improved resistance to environmental contaminant compositions, along with methods of its formation, is provided. The coated component may include a substrate defining a surface, a ceramic coating disposed on the surface of the substrate, and a reactive phase coating disposed on the layer of environmental contaminant compositions. The ceramic coating includes a plurality of slots disposed in the ceramic coating forming segments of ceramic coating material.