Titanium Fire-Containment Coating With High-Melting Bondcoat
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Solution Overview
Problem
Existing fire containment coatings for titanium components in gas turbine engines fail due to melting of the bondcoat, leading to delamination of the ceramic barrier coat, which compromises fire protection in high-temperature and high-pressure compressor sections.
Innovation Solution
A bondcoat with a higher melting point than the titanium substrate, composed of chromium-based alloys, is applied to titanium components, followed by a ceramic barrier coat, enhancing fire protection by preventing bondcoat melting and maintaining the integrity of the coating system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bondcoat is used on titanium components, then the coating provides thermal insulation and fire protection, but the bondcoat melts at high temperatures causing delamination of the ceramic barrier coat and compromising fire protection
Solution Approach 1:
The bondcoat composition is modified by adjusting the chromium content to at least 50 weight percent and adding nickel (at least 6.0 percent) and/or cobalt (at least 10.0 percent), which changes the melting point parameter to be higher than that of the titanium substrate, preventing melt-through and maintaining fire protection reliability
Solution Approach 2:
A composite bondcoat system is used combining chromium-based alloys with nickel and/or cobalt to create a multi-element alloy that achieves a melting point higher than pure chromium-based coatings, providing both thermal insulation and fire protection while preventing delamination
2Reliability
If the bondcoat melting point is increased above the substrate melting point, then fire protection reliability is improved, but the coating system complexity increases
Solution Approach 1:
The bondcoat composition parameters are optimized with chromium at least 50 weight percent, nickel at least 6.0 percent, and cobalt at least 10.0 percent, achieving the desired melting point elevation through controlled compositional changes rather than complex multi-layer structures
Solution Approach 2:
The invention extracts and emphasizes the specific compositional requirements (Cr ≥50%, Ni ≥6.0%, Co ≥10.0%) as the key differentiator, separating the essential elements needed for high-temperature stability from unnecessary coating 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 new coating system provides enhanced fire protection by ensuring the bondcoat does not melt, thereby maintaining the integrity of the ceramic barrier coat and preventing fire propagation in titanium components under extreme conditions.
Implementation Method 1
The barrier coating provides thermal insulation
Implementation Method 2
the bondcoat and the ceramic barrier coat... maintaining the integrity of the coating system
Data Source
Figure 1
Figure 1A
Figure 1B~1C
AI summary
A coated substrate comprises: a metallic substrate; a bondcoat atop the substrate; and a ceramic barrier coat atop the bondcoat. The bondcoat has a combined content of one or more of molybdenum, chromium, and vanadium of at least 50 percent by weight.