Silver-Indium Alloy Coating for High-Temperature Metallic Seals
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Solution Overview
Problem
Existing metal seals fail to maintain sealing integrity at high temperatures and pressures due to defects and require costly gold coatings for enhanced performance.
Innovation Solution
A process involving a silver-indium alloy coating is applied to metal seals, comprising a base metal with intermediate nickel and silver layers, followed by an indium layer, which is diffused during baking to form a corrosion-resistant alloy layer, reducing costs and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gold coating is applied to metallic seals to enhance sealing characteristics at high temperatures, then sealing integrity is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive gold coating with a cheaper silver-indium alloy coating system. The silver base layer provides structural foundation while the indium diffusion layer (0.5-2.0 microns thick) provides the necessary sealing characteristics at high temperatures, achieving comparable performance to gold at lower cost.
Solution Approach 2:
The patent uses a composite coating structure consisting of multiple layers: a silver base layer (1-5 microns), an intermediate layer (nickel or copper, 0.5-2.0 microns), and an indium diffusion layer (0.5-2.0 microns). This composite structure combines the advantages of each material to achieve high-temperature sealing integrity without using gold.
2Ease of manufacture
If conventional silver coating is applied to metallic seals, then manufacturing cost is reduced, but sealing integrity at high temperatures deteriorates due to defects
Solution Approach 1:
The patent applies an intermediate layer (nickel or copper) between the silver base layer and the indium top layer. This intermediate layer is applied in advance to prevent defect formation and ensure proper adhesion, thereby maintaining sealing integrity at high temperatures while using cheaper materials.
Solution Approach 2:
The patent controls the thickness parameters of each layer precisely: silver base layer (1-5 microns), intermediate layer (0.5-2.0 microns), and indium layer (0.5-2.0 microns). This parameter optimization ensures that the coating provides adequate sealing characteristics without excessive material usage, maintaining cost-effectiveness while improving reliability.
3Reliability
If a multi-layer coating system is applied to metallic seals, then sealing characteristics are enhanced, but device complexity increases
Solution Approach 1:
The patent assigns specific functions to different layers: the silver base layer provides structural foundation and adhesion to the metal seal, the intermediate layer (nickel or copper) prevents defects and enhances adhesion, and the indium top layer provides the sealing characteristics at high temperatures. Each layer has optimized thickness (silver: 1-5 microns, intermediate: 0.5-2.0 microns, indium: 0.5-2.0 microns) tailored to its specific function, achieving enhanced sealing characteristics without excessive 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 silver-indium alloy coating enhances sealing characteristics and maintains integrity at temperatures up to 1750°F, outperforming comparative examples in high-temperature and high-pressure applications while reducing costs compared to gold coatings.
Implementation Method 1
baking the base metal with applied intermediate and coating layers at a temperature to diffuse first and second coating layers to form a silver indium alloy coating layer
Data Source
AI summary
A process for the manufacture of a metallic seal comprising applying a first intermediate layer to a base metal, applying a second intermediate layer overlying the first intermediate layer, applying a first coating layer comprising silver overlying the second intermediate layer, applying a second coating layer comprising indium overlying the first coating layer, baking the base metal with applied intermediate and coating layers at a temperature to diffuse the coating layers to form a silver indium alloy coating layer. A seal comprising a substrate having a metal surface, a first intermediate layer overlying the base metal, a second intermediate layer overlying the first intermediate layer, an alloy coating layer overlying the second intermediate layer, wherein the alloy coating layer comprises a silver indium alloy.