ClF Storage Container Passivation for Corrosion and Purity Control
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Solution Overview
Problem
Fluorine-based gases containing chlorine fluoride are highly reactive and corrosive at high temperatures, posing challenges in etching and cleaning processes due to vigorous reactions with equipment components, leading to corrosion and damage.
Innovation Solution
A storage container with a passive fluoride film coating on its inner surface, made from materials like manganese steel or stainless steel, and a valve with a gold plating layer, designed to curb fluorinating reactions and adsorption, ensuring safe handling of ClF at high purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fluorine-based gases containing chlorine fluoride are used at high temperatures, then etching and cleaning efficiency is improved, but corrosion damage to equipment components worsens
Solution Approach 1:
A passive film of fluoride is introduced as an intermediary layer between the ClF gas and the storage container material. This film acts as a mediator that allows the ClF gas to be stored and handled while preventing direct corrosive interaction with the container walls, thus enabling high temperature processing without equipment damage.
Solution Approach 2:
The storage container employs a composite structure combining a base material (such as stainless steel or aluminum alloy) with a protective passive fluoride film layer. This composite material system provides both the mechanical strength of the base material and the chemical resistance of the fluoride film, resolving the contradiction between durability and reactivity.
2Device complexity
If ClF is stored in conventional containers, then storage is simplified, but ClF concentration reduction due to adsorption and reaction worsens
Solution Approach 1:
The passive fluoride film serves as an intermediary barrier that prevents ClF molecules from adsorbing onto or reacting with the container material. This mediator layer maintains high ClF concentration by blocking direct contact between the gas and container walls, while the container structure remains relatively simple.
Solution Approach 2:
The passive fluoride film creates an inert environment within the storage container, similar to how inert gases are used to prevent unwanted reactions. The film chemically passivates the container surface, making it effectively inert to ClF, thus preventing concentration reduction without complicating the storage design.
3Reliability
If passive film thickness is increased, then corrosion protection is improved, but manufacturing precision requirements worsen
Solution Approach 1:
The patent specifies an optimal parameter range for passive film thickness (5nm to 50nm) that balances corrosion protection with manufacturing feasibility. Within this range, the film provides sufficient protective function while remaining achievable through conventional passivation processes, avoiding excessive manufacturing precision requirements.
Solution Approach 2:
The passive film forms through a self-service mechanism where the material naturally develops the protective layer through controlled exposure to fluorine-containing environments. This self-passivation process automatically regulates film formation without requiring precise external control, reducing manufacturing precision demands while ensuring adequate corrosion protection.
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 solution effectively prevents corrosion and maintains high ClF concentration by forming a passive film on the storage container and valve components, allowing safe and stable storage and use of ClF.
Implementation Method 1
a passive film of fluoride formed by contact with a gas containing ClF
Implementation Method 2
curb fluorinating reaction and adsorption of ClF that contacts it
Data Source
Figure 1
Figure 2~3
AI summary
A material at least partly coated with a passive film (28) of fluoride formed by contact with a gas containing ClF.