Ta-Mo-W Composite Charging Device for Capacitor Thermal Treatment
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Solution Overview
Problem
Charging devices made of tantalum (Ta) suffer from low high-temperature and creep resistance, leading to insufficient dimensional stability, especially under long-term use or cyclic stress, and conventional high-alloy Ta alloys contaminate Ta capacitors when used.
Innovation Solution
A charging device comprising areas of high Ta content (>90% by mass) and areas of molybdenum (Mo) or tungsten (W) alloys (>90% by mass) with a layered composite structure, where Ta or Ta alloys are applied via cold gas spraying to prevent contamination and enhance heat and creep resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If charging devices are made of Ta to avoid cross contamination, then contamination of Ta capacitors is prevented, but high-temperature and creep resistance deteriorate leading to insufficient dimensional stability
Solution Approach 1:
The charging device employs a composite structure consisting of a Ta inner layer in contact with the capacitor and a Mo or W outer layer providing structural support. This composite design allows the Ta layer to prevent contamination while the Mo/W layer provides the necessary high-temperature strength and creep resistance that pure Ta lacks.
Solution Approach 2:
Different regions of the charging device are assigned different material properties: the inner surface contacting the capacitor is made of Ta to prevent contamination, while the outer structural regions are made of Mo or W to provide thermal stability and mechanical strength. This local differentiation resolves the contradiction between contamination prevention and structural performance.
2Strength
If conventional high-alloy Ta alloys (e.g., Ta-10% W) are used to improve heat resistance, then creep resistance improves, but contamination of Ta capacitors occurs due to dissolved alloying elements
Solution Approach 1:
Instead of using high-alloy Ta where alloying elements dissolve into the Ta matrix and contaminate capacitors, the invention uses a composite of pure Ta combined with Mo or W layers. The Mo/W provide the necessary creep resistance without dissolving into the Ta, thus preventing contamination while maintaining structural integrity at high temperatures.
3Stability of the object's composition
If micro-alloyed Ta (e.g., with Y or Si) is used to improve high-temperature stability, then dimensional stability improves slightly, but creep resistance remains insufficient
Solution Approach 1:
The patent combines Ta with Mo or W in a composite structure to achieve superior creep resistance compared to micro-alloyed Ta. The Mo/W layers provide the necessary high-temperature strength and creep resistance that cannot be achieved through minor alloying additions alone, while maintaining dimensional stability.
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 provides a charging device with improved high-temperature and creep resistance, maintaining dimensional stability even at elevated temperatures and preventing contamination of Ta capacitors, with low interdiffusion and minimal material loss during the coating process.
Implementation Method 1
Ta or Ta alloys are applied via cold gas spraying to prevent contamination and enhance heat and creep resistance
Data Source
AI summary
The invention relates to a charging device comprising at least one portion made of Mo, a Mo alloy containing > 90 wt% Mo, W, a W alloy containing > 90 wt% W, or a Mo-W alloy containing a combined total of > 90 wt% Mo + W, and at least one portion made of Ta or a Ta alloy containing > 90 wt% Ta. Said charging device has excellent dimensional stability when used in high-temperature furnaces. In addition, there is no cross-contamination of the burning material.