X-ray Cathode Filament Vanadium Bonding
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Solution Overview
Problem
Existing X-ray cathode filaments face challenges in maintaining mechanically stable and good electrical contact at high temperatures due to the connection between the W-based heating filament and refractory metal or alloy mounting pins, which is critical for applications like MOCVD and high-temperature heating structures.
Innovation Solution
The use of vanadium or a V-based alloy as a filler material to connect the W-based heating filament wire end sections to high-melting metal or alloy mounting pins, providing a stable and electrically conductive bond through a receptacle design that allows for localized melting and diffusion, enhancing the connection's high-temperature stability and avoiding intermetallic phase formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional joining methods (spot welding, soldering) are used to connect W-based heating filament to high-melting-point metal mounting pins, then mechanical attachment is achieved, but mechanical stability and electrical contact deteriorate at high temperatures
Solution Approach 1:
A filler material made of V or V-based alloy is introduced as an intermediary substance between the W-based heating filament and the high-melting-point metal mounting pins. This filler material forms a metallurgical bond with both components, serving as a mediator that enables reliable connection at high temperatures where direct joining methods fail.
Solution Approach 2:
The connection structure is designed as a composite system comprising three materials: the W-based heating filament, the V or V-based alloy filler material, and the high-melting-point metal mounting pins. This composite approach leverages the complementary properties of each material to achieve mechanical stability and electrical conductivity at high operating temperatures.
2Temperature
If high-melting-point metals are used for mounting pins to withstand high temperatures, then temperature resistance is improved, but joining difficulty increases due to material incompatibility
Solution Approach 1:
The V or V-based alloy filler material acts as an intermediary that is metallurgically compatible with both the W-based heating filament and the high-melting-point metal mounting pins. This intermediary enables the joining of two incompatible materials by forming intermediate metallurgical bonds that would not be possible through direct joining.
3Ease of manufacture
If conventional filler materials are used for joining, then joining process is simplified, but intermetallic phase formation occurs reducing connection stability
Solution Approach 1:
The selection of V or V-based alloy as filler material represents a specific parameter change in the joining process. Vanadium's unique properties - including its melting point, reactivity characteristics, and ability to form stable bonds with both W and high-melting-point metals - are leveraged to prevent intermetallic phase formation while maintaining connection stability at high temperatures.
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 solution ensures a mechanically stable and electrically reliable connection at high temperatures, offering advantages in terms of lower joining temperature, higher melting point, reduced vapor pressure, cost-effectiveness, and compatibility with high-vacuum environments, while preventing intermetallic phase formation that can reduce stability.
Implementation Method 1
the additive material obtained after subsequent cooling is metallurgically bonded to the wire end section and to the retaining pin... Heating at least a part of the initial additive material in such a way that the additive material obtained after subsequent cooling is metallurgically bonded
Implementation Method 2
the additive material obtained after subsequent cooling is metallurgically bonded to the wire end section and to the retaining pin, thus obtaining a metallurgical bond between the retaining pin and the wire end section
Implementation Method 3
providing a stable and electrically conductive bond through a receptacle design that allows for localized melting and diffusion
Data Source
Figure 1~2
Figure 3~5
AI summary
The present invention relates to a filament, particularly an x-ray cathode filament (2), having at least one emitter or heating filament (4) made from a W-based material with projecting wire end sections (6, 8) and mounting pins (12, 14) made from a high melting point metal or a high melting point alloy, each associated with a respective wire end section (6, 8) in order to fix and electrically contact the wire end sections (6, 8). The invention further relates to a corresponding production method. At least one mounting pin (12, 14) has a receptacle (18) on the end face thereof, in which a wire end section (6, 8) is received and is materially bonded to the mounting pin (12, 14) inside the receptacle (18). The material bond is produced via an additional material made from V or a V-based alloy, which is materially bonded to the wire end section (6, 8) and materially bonded to the mounting pin (12, 14).