Creep Resistant Flat Emitter via Hot Isostatic Pressing
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Solution Overview
Problem
Conventional flat emitters for x-ray tubes suffer from reduced creep resistance and shorter lifespan due to lower deformation during material processing, leading to non-uniform electron emission and focal spot profiles, which are sensitive to placement and prone to creep at high operating temperatures.
Innovation Solution
A flat emitter is formed by consolidating preforms, such as wires, through processes like hot isostatic pressing to create a non-porous structure with enhanced creep resistance and thermomechanical properties, eliminating voids and retaining the beneficial properties of wire-formed emitters, thereby improving the emitter's durability and electron emission uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional flat emitters are used, then manufacturing cost is reduced and placement tolerance is relaxed, but creep resistance is reduced and lifespan is shortened
Solution Approach 1:
The emitter is constructed as a composite structure consisting of multiple wire segments assembled together to form a flat emitter face. This composite approach combines the creep resistance of wire-formed materials with the manufacturing advantages and uniform electron emission characteristics of flat emitters, resolving the contradiction between ease of manufacture and creep resistance
Solution Approach 2:
The flat emitter is segmented into multiple individual wire segments that are assembled together. Each wire segment maintains its inherent creep resistance properties while collectively forming a flat emitter surface that provides uniform electron emission and relaxed placement tolerance
2Ease of manufacture
If rolled sheet material is used for flat emitters, then manufacturing is simplified, but deformation processing is reduced and creep resistance decreases
Solution Approach 1:
Instead of using rolled sheet material, the invention uses a composite structure of assembled wire segments. The wire segments incorporate deformation processing and strengthening mechanisms during their fabrication, providing superior creep resistance while maintaining the flat emitter geometry and manufacturing simplicity
3Ease of manufacture
If conventional flat emitters with rolled sheets are used, then manufacturing is easier, but electron emission uniformity and focal spot profiles become non-uniform
Solution Approach 1:
Each wire segment in the composite flat emitter maintains its own localized emission characteristics that are inherently uniform due to the wire formation process. The assembly of these segments with controlled spacing and orientation ensures uniform electron emission across the entire flat emitter surface, achieving both manufacturing ease and emission uniformity
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 results in a flat emitter with increased creep resistance and longer lifespan, maintaining high temperature properties and uniform electron emission, addressing the limitations of conventional flat emitters by enhancing the emitter's mechanical strength and operational reliability.
Implementation Method 1
consolidating preforms, such as wires, through processes like hot isostatic pressing to create a non-porous structure
Implementation Method 2
The formation of the wire in a suitable drawing process provides sufficient deformation processing to the material in order to result in a creep resistance imparted through subsequent annealing of the material
Implementation Method 3
a filament is included that may be induced to release electrons through the thermionic effect, i.e. in response to being heated
Data Source
AI summary
In the present invention, a flat emitter is formed by the formation of emitter material wires into a unitary non-porous flat emitter structure. The wires are formed with increased yield and tensile strength as a result of the manner of the formation of the emitter material or metal into the wires that is transferred to the flat emitter. To form the flat emitter, the wires are encapsulated and subjected to sufficient temperatures and pressure in a hot isostatic pressing treatment/process to increase the density of the wires into a solid sheet without the presence of voids or pores in the sheet. In forming the emitter sheet in this manner, the strength properties from the wires are retained within the sheet to provide the emitter with increased creep resistance and a consequently longer useful life in the x-ray tube.