Thick Titanium Gettering Layer for Vacuum Pumping Capacity
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Solution Overview
Problem
Current vacuum components with gettering effects face limitations in maximum captured molecules and working life due to thin NEG coating layers, which restrict their pumping capacity and reactivation cycles.
Innovation Solution
A vacuum component with a Ti layer of 100 μm or larger thickness, where the Ti layer is either oxide-free or has a thin Ti oxide layer, and an electrode for generating DC discharge to enhance gettering capacity, allowing for a thicker coating layer and increased reactivation cycles without oxidation suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a thin NEG coating layer is used, then the pumping speed for hydrogen is improved, but the maximum number of captured molecules is limited
Solution Approach 1:
The patent changes the thickness parameter of the Ti layer from the conventional thin film (about 1 μm) to a thick layer (100 μm or larger), fundamentally altering the pumping mechanism from surface-limited to volume-based hydrogen capture, thereby increasing the maximum number of captured molecules while maintaining high pumping speed
2Power
If a thin NEG coating layer is used, then the initial pumping capacity is improved, but the working life and reactivation cycles are limited
Solution Approach 1:
The patent changes the thickness parameter of the Ti layer from thin film to thick layer (100 μm or larger), which fundamentally alters the reactivation mechanism. The thick Ti layer provides a large reservoir of titanium atoms that can diffuse to the surface during reactivation, enabling many more reactivation cycles before the layer is depleted, thus extending working life from limited cycles to potentially hundreds or thousands of cycles
3Reliability
If a noble metal layer is formed on the NEG coating layer, then oxidation suppression is improved, but the ability to capture carbon dioxide and nitrogen is lost
Solution Approach 1:
The patent extracts and removes the noble metal layer from the coating structure, relying instead on the thick Ti layer itself to provide both oxidation resistance and broad gas capture capability. The thick Ti layer can form protective oxides on its surface while still maintaining the ability to capture various gases including carbon dioxide and nitrogen through diffusion and chemical reactions in the bulk material
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 configuration achieves a higher maximum number of captured molecules and extended working life by maintaining a high pumping capacity over time, with the ability to reactivate the vacuum component multiple times without significant degradation.
Implementation Method 1
hydrogen molecules are diffusion-captured into the NEG coating layer
Implementation Method 2
a vacuum component having a pumping capacity by means of a gettering effect of titanium (Ti)
Implementation Method 3
a state where DC discharge is generated between the electrode surface and the inner surface
Data Source
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AI summary
Provided is a vacuum component capable of evacuation by a getting effect, which has a large maximum number of captured molecules and a long working life. It is provided, in an area around its central axis, with a hollow cylindrical electrode 20 having an electrode surface 20A that is sufficiently smaller than an inner surface 10A of the vacuum container 10, along the central axis. In the vacuum container 10, it is possible to realize any one of states among a first state of generating DC discharge by introducing Ar into the inside and setting the electrode surface 20A at a positive potential, a second state of setting the electrode surface 20A at a ground potential without introducing Ar, and a third state of generating DC discharge by introducing Ar into the inside and setting the electrode surface 20A at a negative potential. Evacuation by the vacuum component 1 is performed in the second state. Further, evacuation by the vacuum component 1 is performed also by realizing a state of performing a heating process at 400 °C or below without using the electrode.