Structured Refractory Metal Anodes for High-Capacitance Sintering
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Solution Overview
Problem
High-capacitance powders used in capacitor production suffer from significant loss of specific surface area during sintering, making it challenging to achieve high capacitance values due to increased sinter-activity, and existing methods for creating sinter-active surfaces are laborious or inefficient.
Innovation Solution
A structured surface is created on refractory metal products through oxidation and subsequent reduction, increasing the specific surface area by a factor of 10 to 100,000, allowing for better bonding with high-capacitance materials and reduced sintering temperatures, using techniques like anodic oxidation and magnesium vapor reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacitance powders with increased specific surface area are used, then the volume yield of capacitance increases, but the loss of specific surface area during sintering becomes greater
Solution Approach 1:
The semifinished product surface is pre-treated with oxidation and reduction processes to create a structured, sinter-active surface before the actual sintering step. This preliminary structuring enables the surface to be more sinter-active at lower temperatures, thereby preserving the specific surface area of the high-capacitance powders during sintering.
Solution Approach 2:
The invention changes the surface parameters of the semifinished product by creating an oxidized and re-reduced structured surface. This surface transformation increases sinter-activity, allowing the process to proceed at lower temperatures where powder surface area loss is minimized.
2Quantity of substance
If sintering temperature is reduced to minimize surface area loss, then specific surface area is preserved, but the bonding of powder to anode conductor deteriorates
Solution Approach 1:
The invention applies local quality enhancement by structuring only the surface layer of the semifinished product. This localized surface structuring creates high sinter-activity at the bonding interface without requiring bulk heating to high temperatures, thus maintaining powder surface area while achieving strong bonding.
Solution Approach 2:
The surface parameters of the semifinished product are changed through oxidation and reduction to create a structured surface with enhanced sinter-activity. This parameter change enables effective bonding at lower temperatures where powder surface area is preserved.
3Ease of manufacture
If conventional smooth surfaces are used, then manufacturing is simpler, but sintering activity is low and bonding with powders is poor
Solution Approach 1:
The surface parameters are changed from smooth to structured through controlled oxidation and reduction. This transformation dramatically increases sintering activity and bonding capability while maintaining process simplicity through established electrochemical techniques.
Solution Approach 2:
The invention creates a porous or structured surface morphology through oxidation and reduction. This porous structure provides increased surface area and sintering sites, dramatically enhancing sintering activity and powder bonding capability.
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 treated products exhibit significantly higher capacitance values and improved sintering activity, enabling stable bonding of high-capacitance materials at lower temperatures, reducing surface area loss and maintaining mechanical stability and voltage peak stability.
Implementation Method 1
containing an oxidized and then re-reduced surface
Implementation Method 2
containing an oxidized and then re-reduced surface
Data Source
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AI summary
The invention comprises semifinished products with a structured surface, the semifinished product comprising an oxidized and subsequently re-reduced surface containing at least one refractory metal, and also a process for their production and their use for producing high-capacitance components.