Rare Earth Silicate Bond Layer for Thermal Barrier Coatings
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Solution Overview
Problem
High-temperature mechanical system components, such as gas turbine engine components, face challenges with phase instability and increased manufacturing costs due to the high-temperature application of mullite-based bond layers, which can lead to cracking and delamination in environmental barrier coatings.
Innovation Solution
A coating with a bond layer comprising a rare earth silicate and a second phase, such as silicon, alkali metal oxides, or glass ceramics, which can be deposited at room temperature without phase instability, enhancing adherence and reducing manufacturing costs by eliminating the need for additional silicon or mullite-based bond layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mullite-based bond layers are applied at high temperature to achieve proper bonding, then bonding capability is improved, but phase instability occurs leading to cracking and delamination
Solution Approach 1:
The patent changes the deposition temperature parameter from high temperature to room temperature, which prevents phase instability and cracking while maintaining bonding capability through the unique composition of rare earth silicate combined with silicon, silicides, or glass ceramics
Solution Approach 2:
The patent creates a composite bond layer by combining rare earth silicate with at least one of silicon, silicides, or glass ceramics. This composite structure provides both bonding capability and phase stability, eliminating the cracking and delamination issues associated with pure mullite-based coatings
2Reliability
If multiple bond layers (silicon or mullite-based) are applied to ensure adequate bonding, then bonding reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the functions of multiple separate bond layers into a single composite bond layer. The rare earth silicate combined with silicon, silicides, or glass ceramics provides both bonding and protective functions that previously required multiple layers, thereby simplifying the coating structure and reducing manufacturing complexity
Solution Approach 2:
The composite bond layer serves multiple functions simultaneously: it provides bonding to the substrate, prevents cracking, prevents delamination, and maintains phase stability. This multi-functional single layer replaces what previously required multiple specialized layers, reducing overall system complexity
Data Source
AI summary
A coating including a bond layer deposited on a substrate. The bond layer includes a rare earth silicate and a second phase, the second phase including at least one of silicon, silicides, alkali metal oxides, alkali earth metal oxides, glass ceramics, Al2O3, TiO2, Ta2O5, HfO2, ZrO2, HfSiO4, ZrSiO4, HfTiO4, ZrTiO4, or mullite. The coating may provide thermal and/or environmental protection for the substrate, especially when the substrate is a component of a high-temperature mechanical system.