Passive Fluoride Coating for ClF Storage Containers and Valves

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Solution Overview

Problem

Fluorine-based gases, such as ClF, are highly reactive and corrosive, making it challenging to control reactions and store them safely at high temperatures due to their reactivity with equipment components, leading to corrosion and reduced concentration.

Innovation Solution

A storage container and valve system coated with a passive fluoride film, using materials like manganese steel and gold, with a gold plating layer to prevent fluorinating reactions and adsorption, allowing for safe handling of ClF at high purity by forming a fluoride passive film on the gas-contacting regions with a gas containing ClF.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fluorine-based gases (ClF, ClF3, ClF5) are used for etching and cleaning at high temperatures, then etching and cleaning effectiveness is improved, but the gas reacts vigorously with equipment components causing serious corrosion damage

Engineering Contradiction:

Improveetching and cleaning effectivenessVSAvoidcorrosion damage to equipment

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

A passive film of fluoride is formed on the inner surface of the storage container and valve components. This passive film acts as an intermediary barrier between the ClF gas and the underlying material, preventing direct contact and thus preventing corrosion while allowing the gas to be stored and handled safely

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The storage container and valve components use composite material structures: a base material (such as steel or alloy) providing mechanical strength, combined with a surface layer (passive fluoride film) providing chemical resistance. This composite structure simultaneously achieves both corrosion resistance and mechanical integrity

Inventive Principle:

Principle #40Composite materials

2Device complexity

If ClF is stored in conventional containers without special coating, then storage simplicity is maintained, but ClF concentration reduces due to adsorption and fluorinating reactions with container walls

Engineering Contradiction:

Improvestorage container structureVSAvoidClF concentration

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The passive fluoride film serves as an intermediary layer between the ClF gas and the container wall material. This film prevents direct interaction that would cause adsorption or fluorinating reactions, thereby maintaining ClF concentration while allowing use of conventional container structures

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The passive fluoride film creates an inert environment on the container surface. This chemically inert surface layer prevents reactive interactions between ClF and the container material, effectively reducing adsorption and maintaining gas concentration without requiring complex storage designs

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Ease of manufacture

If valve components are made of standard materials without special coating, then manufacturing simplicity is maintained, but fluorinating reactions occur causing component degradation and leakage

Engineering Contradiction:

Improvevalve component fabricationVSAvoidvalve sealing performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A passive fluoride film is formed on valve components including the valve seat and valve member surfaces. This film acts as an intermediary protective layer that prevents fluorinating reactions between ClF and the valve materials, maintaining sealing surfaces integrity and preventing leakage while allowing use of standard valve designs

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The surface chemistry of valve components is changed by forming a passive fluoride film. This parameter change (surface composition) transforms the surface from reactive to inert, preventing degradation and maintaining reliable sealing performance without changing the bulk material properties or valve structure

Inventive Principle:

Principle #35Parameter changes

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 passive film coating effectively curbs fluorinating reactions and adsorption, maintaining ClF concentration and ensuring safe handling by reducing corrosion and maintaining the integrity of the storage container and valve components.

Implementation Method 1

the passive film coating effectively curbs fluorinating reactions and adsorption, maintaining ClF concentration

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

a passive film of fluoride formed by contact with a gas containing ClF

Methodology Applied

Scientific EffectPassive film formation: Deposition (physical)

Data Source

PatentUS10982811B2Material, storage container using the material, valve attached to the storage container, method of storing ClF and method of using ClF storage container

Publication Date: 2021.04.20 KANTO DENKA IND CO LTD

AI summary

A material at least partly coated with a passive film of fluoride formed by contact with a gas containing ClF.