Copper Alloy Wire Rod with Silver Precipitates for Micro Speaker Durability
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Solution Overview
Problem
Current copper alloy wire rods used in micro speakers lack sufficient vibration durability and heat resistance, particularly when thinned for smaller devices, leading to potential disconnection and reduced performance in high-frequency applications.
Innovation Solution
A copper alloy wire rod with Ag content between 0.5 wt% and 6 wt%, combined with a manufacturing process involving high cooling rates during casting, wire drawing, and heat treatment to create a microstructure with dispersed Ag particles, enhancing both vibration durability and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the wire rod is thinned for downsizing, then the size of electronic devices is reduced, but heat resistance and vibration durability deteriorate due to increased electric resistance and vibration
Solution Approach 1:
The invention changes the microstructural parameters of the wire rod by controlling the size, shape, and distribution of crystallized precipitates. Specifically, it creates precipitates with a maximum length of 100 nm or less in a rectangular range of 2.3 μm × 1.7 μm, which provides optimal strength and vibration durability even in thinned wire rods
Solution Approach 2:
The invention uses a composite microstructure consisting of copper matrix with dispersed silver crystallized precipitates. This composite structure at the micro-scale provides both the mechanical strength needed for vibration durability and the electrical conductivity required for thin wire rods
2Volume of moving object
If the wire rod is thinned for downsizing, then the size of electronic devices is reduced, but heat resistance deteriorates due to increased electric resistance
Solution Approach 1:
The invention optimizes the microstructural parameters including precipitate size (100 nm or less), shape (rectangular distribution), and silver content (0.5-6 wt%) to reduce electric resistance while maintaining mechanical integrity, thereby improving heat resistance in thinned wire rods
3Strength
If silver is added to copper to improve strength, then vibration durability is improved, but electric conductivity decreases
Solution Approach 1:
The invention precisely controls the silver content parameter within 0.5-6 wt% and optimizes the precipitate size parameter to 100 nm or less, creating an optimal balance where the copper matrix maintains high electrical conductivity while the dispersed silver precipitates provide sufficient strength and vibration durability
Solution Approach 2:
The invention applies local quality by concentrating silver in discrete crystallized precipitates distributed throughout the copper matrix, rather than uniform mixing. This allows the copper matrix to maintain its excellent electrical conductivity while the localized silver precipitates provide strength reinforcement
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 copper alloy wire rod with significantly improved vibration durability and heat resistance, capable of withstanding high-cycle fatigue and high-temperature environments, ensuring reliable performance in micro speakers.
Implementation Method 1
a property in which strength is improved due to appearance of silver added into copper as crystallized precipitates
Implementation Method 2
a property in which a decrease in electric conductivity is small even when silver is added into copper while electric conductivity is generally decreased when an additive element is solid dissolved in cupper
Data Source
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AI summary
A copper alloy wire rod containing Ag: 0.5 wt% or more and 6 wt% or less and the balance including inevitable impurities and Cu, in which, on a cross section parallel to a longitudinal direction of the copper alloy wire rod, within a range observed with a visual field of 1.7 µm in a direction perpendicular to the longitudinal direction and 2.3 µm in a direction parallel to the longitudinal direction, the copper alloy wire rod has at least one rectangular range that is a rectangular range having a width perpendicular to the longitudinal direction of 0.2 µm and a length parallel to the longitudinal direction of 2.3 µm and entirely includes five or more second phase particles containing Ag and having a maximum length in the longitudinal direction of less than 300 nm.