Getter Activation Near Tammann Temperature for High Surface Area
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Solution Overview
Problem
Existing getter compositions, such as non-evaporable getters (NEG), are limited by their low active surface area, which hinders effective contaminant removal in environments like vacuum packaging and gas purification.
Innovation Solution
A method involving heating reduced and passivated getter materials containing metal crystallites encapsulated by an oxide layer to a specific temperature range (TT−X to TT+Y) forms an activated getter with a higher surface area, suitable for contaminant removal, where TT is the Tammann temperature of the metal, and X and Y are defined ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-evaporable getter (NEG) alloys are used, then the getter material can maintain vacuum and remove contaminants, but the metal surface area is very low (less than 0.2 m2/g)
Solution Approach 1:
The patent applies porous materials by using highly porous substrates (foams, ceramics, or sintered metals) with surface areas exceeding 100 m2/g as the base structure for the getter material. This porous structure provides a vast internal surface area that dramatically increases the active metal surface area available for contaminant adsorption, directly resolving the contradiction between maintaining vacuum reliability and increasing surface area.
Solution Approach 2:
The patent employs composite materials by combining porous substrate materials with getter-active metal materials (such as titanium, zirconium, or their alloys). The composite structure integrates the high surface area characteristics of porous materials with the contaminant-removal properties of getter metals, enabling both high surface area and effective vacuum maintenance simultaneously.
2Reliability
If the getter material is heated to activate it, then the surface becomes active for contaminant removal, but the heating process requires precise temperature control around the Tammann temperature
Solution Approach 1:
The patent applies parameter changes by utilizing the Tammann temperature characteristic of getter metals (approximately half the melting point) as a critical activation parameter. By heating the porous getter material to this specific temperature range, the metal crystallites undergo structural changes that dramatically increase surface activity. The porous structure enhances this effect by providing numerous nucleation sites and reducing the overall heating burden, making temperature control more manageable while achieving reliable surface activation.
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 method significantly increases the active surface area of getters, enabling more effective removal of contaminants like hydrogen, water, oxygen, and carbon dioxide, preserving vacuum and maintaining gas purity in containers.
Implementation Method 1
heating a reduced and passivated getter material containing crystallites of a metal in elemental form encapsulated by a layer comprising an oxide of the metal to a temperature in the range (TT−X) to (TT+Y), where TT is the Tammann temperature of the metal in elemental form
Implementation Method 2
The heating step produces an activated getter material having a surface active for the removal of the contaminant
Implementation Method 3
These alloys may be thermally activated to produce metal surfaces that adsorb or absorb contaminant gases such as hydrogen, water, oxygen and carbon oxides
Implementation Method 4
These alloys may be thermally activated to produce metal surfaces that adsorb or absorb contaminant gases such as hydrogen, water, oxygen and carbon oxides
Data Source
AI summary
A method for removing a contaminant from an environment is described comprising the steps of: (i) heating a reduced and passivated getter material containing crystallites of a metal in elemental form encapsulated by a layer comprising an oxide of the metal to a temperature in the range (TT−X) to (TT+Y), where TT is the Tammann temperature of the metal in elemental form in degrees Centigrade, X is 400 and Y is 200, to form an activated getter material having active surface for contaminant removal and (ii) exposing the activated getter material to the environment containing the contaminant.