Stainless Steel Passivation Film Moisture Desorption
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Solution Overview
Problem
Stainless steel components in processing apparatuses are prone to corrosion due to moisture trapped in passivation films, leading to metallic contamination, as existing methods either fail to effectively remove chemically adsorbed moisture or are costly and unsuitable for complex shapes.
Innovation Solution
A method involving heating stainless steel components to 300° C. or higher to desorb chemically adsorbed moisture from the passivation film, effectively reducing corrosion by removing both physically and chemically adsorbed moisture, thereby protecting the chromium passivation film and preventing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bake-out process is applied at low temperature (120-150°C) to remove moisture, then the process is simple and low-cost, but chemically adsorbed moisture in the passivation film remains and corrosion occurs
Solution Approach 1:
The patent applies the parameter changes principle by increasing the bake-out temperature from the conventional 120-150°C to 300°C or higher. This temperature parameter change enables the removal of chemically adsorbed moisture in the passivation film that cannot be removed at lower temperatures, thereby preventing corrosion while maintaining process simplicity.
2Reliability
If high temperature heating (300°C or higher) is applied to remove chemically adsorbed moisture, then corrosion resistance is improved, but energy consumption increases
Solution Approach 1:
The patent applies preliminary action by performing high-temperature heating (300°C or higher) before the stainless steel components are installed or used in the processing apparatus. This preliminary moisture removal prevents corrosion from occurring in the first place, avoiding the need for subsequent maintenance, disassembly, and reprocessing that would consume much more energy.
3Ease of manufacture
If conventional bake-out process is used, then the process is simple, but metallic contamination (Cr, Fe, Ni) and particle generation occur due to corrosion
Solution Approach 1:
The patent applies parameter changes by raising the heating temperature to 300°C or higher, which fundamentally changes the moisture removal mechanism from only physical desorption at low temperatures to including chemical desorption from the passivation film. This parameter change eliminates the corrosion mechanism that generates metallic contamination and particles, while the process remains simple and equipment-free.
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
This approach significantly reduces corrosion and contamination of stainless steel components, ensuring the longevity and reliability of processing apparatuses by maintaining the integrity of the chromium passivation film, even in complex shapes, and preventing metallic contamination.
Implementation Method 1
heating the metal member for a predetermined period at a temperature of 300° C. or higher
Data Source
AI summary
A method of processing a metal member having a passivation film on its surface is provided. The method includes a step of heating the metal member for a predetermined period at a temperature of 300° C. or higher.