Internal Alloy Coatings for Limited-Line-of-Sight Cavities
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Solution Overview
Problem
Existing technologies face challenges in applying surface coatings to internal surfaces of articles that are difficult to access or have a limited line of sight, which hinders the provision of corrosion resistance and enhanced properties.
Innovation Solution
The use of alloy layers comprising molybdenum, tungsten, nickel, cobalt, chromium, and other elements on internal surfaces, which can be applied using various methods to form single or multiple layers, providing corrosion resistance and improved performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coating methods are used on internal surfaces, then coating application is straightforward on accessible surfaces, but internal surfaces with limited line of sight cannot be properly coated
Solution Approach 1:
The patent uses a multi-component coating system where a first component (corrosion inhibitor) is applied to the internal surface, followed by a second component that reacts with it to form a protective coating. This intermediary chemical reaction enables coating formation in areas with limited line of sight where conventional spray methods cannot reach, while still providing reliable corrosion resistance.
2Reliability
If chrome coatings are used to provide corrosion resistance, then corrosion protection is achieved, but hydrogen embrittlement occurs and environmental concerns arise
Solution Approach 1:
The patent converts the harmful effect of moisture and oxygen (which cause corrosion) into a beneficial protective mechanism. The coating system uses these environmental factors to trigger the formation of protective corrosion products that seal the surface, preventing further degradation and eliminating hydrogen embrittlement while maintaining corrosion resistance.
3Reliability
If thick coatings are applied to ensure adequate protection, then corrosion resistance improves, but surface roughness increases and dimensional precision is compromised
Solution Approach 1:
The patent creates a coating system where the protective properties are concentrated in the bulk coating layers, while the outermost surface maintains the substrate's original finish. The corrosion inhibition occurs through localized chemical reactions at the coating-substrate interface and within the coating matrix, allowing adequate protection without adding significant thickness or roughness to the surface.
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 alloy layers exhibit enhanced corrosion resistance and performance, with some configurations offering up to twice the corrosion resistance of chrome coatings and preventing hydrogen embrittlement, while maintaining desired surface roughness and hardness.
Implementation Method 1
The internal surfaces are coated with a corrosion resistant coating that may include a metal or metal alloy such as nickel, cobalt, molybdenum, tungsten, or an alloy or combination thereof
Implementation Method 2
The corrosion resistant coating may be applied to the internal surfaces by any method including, but not limited to, physical vapor deposition, chemical vapor deposition, thermal spray, or slurry spraying
Data Source
AI summary
Coatings that can be used on limited line of sight substrates are described. In some embodiments, the coating may be a metal alloy coating applied to an inner surface of an article such as a rod, tube or pipe. The inner surface can be present within a cavity of an article.