Microwave-Heated Copper Solder Composition for Oxidation Control
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Solution Overview
Problem
Copper solder or braze compositions face challenges in maintaining structural integrity and electrical conductance at elevated temperatures due to oxidation and high melting temperatures, leading to dislodging of electrical components.
Innovation Solution
A copper solder or braze composition comprising copper(II) oxide powder, silicon carbide, and a flux, heated using microwave energy within specific frequency ranges to convert copper(II) oxide to copper metal, optimizing the mass percentages of each component to achieve high conversion efficiency and prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper metal is used for solder or braze, then electrical conductance is improved, but melting temperature becomes too high causing loss of structural integrity at elevated temperatures
Solution Approach 1:
The invention changes the chemical composition parameters by using copper oxide instead of copper metal, and by formulating a specific glass-ceramic matrix composition that enables the solder to maintain structural integrity at elevated temperatures while providing good electrical conductance through the copper oxide particles distributed within the glass-ceramic matrix
Solution Approach 2:
The invention creates a composite material system consisting of copper oxide particles embedded in a glass-ceramic matrix. This composite structure combines the electrical conductance benefits of copper with the high-temperature stability of glass-ceramic, resolving the contradiction between electrical performance and thermal stability
2Reliability
If copper nanoparticles are used, then electrical conductance is improved, but oxidation occurs leading to corrosion and loss of electrical conduction
Solution Approach 1:
The invention converts the potential harm of oxidation by using copper oxide as the active soldering component rather than attempting to prevent oxidation of copper metal. The copper oxide is deliberately used in a controlled environment where it provides both structural integrity and electrical conductance without undergoing further oxidation, thus converting the harmful oxidation effect into a beneficial design feature
3Ease of manufacture
If conventional solder materials are used, then ease of manufacture is improved, but structural integrity is lost at elevated temperatures close to glass transition temperature
Solution Approach 1:
The glass-ceramic matrix provides a composite structure that maintains structural integrity at elevated temperatures while allowing conventional copper oxide-based soldering processes, thus resolving the contradiction between ease of manufacture and high-temperature strength
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 achieves >93% conversion of copper(II) oxide to copper metal, maintaining structural integrity and electrical conductivity while preventing oxidation, thus ensuring reliable soldering or brazing of electrical components at high temperatures.
Implementation Method 1
heating the copper solder or braze composition using a microwave energy source emitting microwave radiation sweeping from 5.85 GHz to 6.65 GHz frequency
Implementation Method 2
heating the copper solder or braze composition using a microwave energy source
Implementation Method 3
copper nanoparticles present issues attributed to oxidation in the air which can lead to corrosion and loss of electrical conduction
Data Source
AI summary
Bulk copper solder is highly desired as a solder compound because it is very electrically conductive and has a high melting point relative to other solders. A composition for a copper solder includes copper(II) oxide powder in the range of 37-53% by mass, silicon carbide (SiC) powder in the range of 8-14% by mass, and a flux in the range of 35%-53% by mass. Energy in the form of microwave energy can be applied to the copper solder to convert the Cu(II)O to Cu, for a Cu product conversion of >93%.