Corrosion-Resistant Coating via Sub-Decomposition CVD
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing coated articles lack sufficient corrosion resistance and are susceptible to degradation in certain environments, particularly due to the limitations of silicon-based chemical vapor deposition materials and the presence of metal catalysts, which can reintroduce undesirable surface activities and dissolve in caustic media.
Innovation Solution
A chemical vapor deposition process where a deposition gas is introduced at a sub-decomposition temperature below the thermal decomposition temperature of the gas, forming a coating on substrates without the use of a catalyst, and subsequently heating the chamber to a super-decomposition temperature to enhance corrosion resistance and impedance properties, specifically resisting corrosion from NaClO and HCl.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical vapor deposition is performed at thermal decomposition temperature to produce coatings with improved characteristics, then coating performance is improved, but corrosion resistance in caustic media deteriorates
Solution Approach 1:
The patent changes the deposition temperature parameter from thermal decomposition temperature to sub-decomposition temperature, and modifies the chemical composition by introducing fluorine-containing compounds. This parameter change resolves the contradiction by producing coatings that achieve improved performance characteristics while simultaneously gaining resistance to caustic media corrosion, as the lower temperature and fluorine incorporation create a more chemically stable coating structure.
2Ease of manufacture
If metal catalysts are used in silicon hydride surface reactions to provide desired performance characteristics, then coating formation is enabled, but undesirable surface activity is reintroduced
Solution Approach 1:
The patent extracts and removes the metal catalyst from the deposition process entirely. By using silane-based precursors that can decompose and react without metal catalysts, the invention eliminates the source of undesirable surface activity while still enabling coating formation through alternative chemical pathways at sub-decomposition temperatures.
3Ease of manufacture
If amorphous silicon-based materials are used for chemical vapor deposition, then coating deposition is achieved, but dissolution in high pH media occurs
Solution Approach 1:
The patent creates a composite coating material by incorporating fluorine-containing compounds into the silicon-based coating matrix. This composite structure combines the beneficial deposition properties of silicon-based materials with the chemical stability and corrosion resistance of fluorinated compounds, resulting in a coating that resists dissolution in high pH media while maintaining ease of manufacture through chemical vapor deposition.
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 process results in coated articles with significantly reduced corrosion rates and impedance degradation, allowing for wider material use, improved wear resistance, and enhanced dielectric properties, including linear polarization-field loops, while avoiding catalyst-related issues and media susceptibility.
Implementation Method 1
heating the chamber to a super-decomposition temperature to enhance corrosion resistance
Implementation Method 2
A chemical vapor deposition process where a deposition gas is introduced at a sub-decomposition temperature
Data Source
AI summary
Coated articles are disclosed. One embodiment of a coated article includes a substrate capable of being subjected to corrosion and a deposited coating on the substrate. The deposited coating has silicon with the substrate resisting corrosion with the deposited coating on the substrate when exposed to 15% NaClO by a rate of at least 5% greater than the corrosion rate of a coating applied with the same process but without introducing the deposition gas at the sub-decomposition temperature and/or the substrate with the deposited coating having a 15% NaClO corrosion rate of between 0 and 3 mils per year.