Clad Material for Electric Contacts with Constrained Diffusion
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Solution Overview
Problem
Conventional clad materials for electric contacts, using precipitation-type age-hardening materials as base materials, face challenges in achieving a balance between higher conductivity and strength, particularly in small-sized electronic devices where improved conductive properties are required, and the diffusion region formed during production negatively affects conduction characteristics.
Innovation Solution
A clad material is developed with a Cu-based, precipitation-type age-hardening material as the base and an Ag alloy as the contact material, where the diffusion region between them is limited to 2.0 μm or less, achieved by optimizing the heat treatment process and composition to enhance conductivity and strength, and the method involves bonding the materials after aging-hardening treatment to suppress the expansion of the diffusion region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a precipitation-type age-hardening material is used as the base material to improve strength, then the tensile strength increases, but the conductivity decreases due to the formation of a diffusion region at the bonded interface
Solution Approach 1:
The base material undergoes aging treatment before bonding with the contact material. This preliminary aging action strengthens the base material in advance, allowing the bonding process to proceed without requiring subsequent high-temperature heat treatment that would expand the diffusion region and harm conductivity.
Solution Approach 2:
The invention changes the timing parameter of the aging treatment from after-bonding to before-bonding. This parameter change transforms the process sequence, enabling the base material to achieve sufficient strength prior to bonding, thereby eliminating the need for post-bonding heat treatment that causes diffusion region expansion.
2Strength
If heat treatment is applied after bonding to achieve age-hardening, then the strength of the base material improves, but the diffusion region expands and negatively affects conduction characteristics
Solution Approach 1:
The aging treatment is performed as a preliminary action before the bonding process. This ensures the base material achieves the required strength prior to bonding, eliminating the need for subsequent heat treatment that would cause the harmful diffusion region to expand and degrade conduction characteristics.
Solution Approach 2:
The invention converts the potentially harmful effect of heat treatment into a beneficial preliminary aging process. By performing aging before bonding, the same thermal mechanism that would otherwise cause harmful diffusion is transformed into a useful strength-enhancing treatment that occurs when it does not harm conductivity.
3Strength
If multiple heat treatment steps are applied during production, then the mechanical properties are improved, but the production process complexity increases and conductivity is compromised
Solution Approach 1:
The invention merges the aging treatment into the pre-bonding preparation step, combining the strength enhancement process with the material preparation phase. This consolidation eliminates the need for separate post-bonding heat treatment steps, simplifying the overall production process while maintaining mechanical properties.
Solution Approach 2:
The aging treatment is performed as a preliminary action before bonding, integrating the mechanical property enhancement into the initial material preparation phase. This eliminates subsequent heat treatment steps, reducing production process complexity while achieving the desired mechanical properties.
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 resulting clad material exhibits higher strength and conductivity, with tensile strength ranging from 400 MPa to 1200 MPa and conductivity from 20% to 90% IACS, effectively addressing the limitations of conventional materials by minimizing the diffusion region's impact on conduction.
Implementation Method 1
a base material having undergone age-hardening treatment and a contact material to bond the base material and the contact material to each other
Implementation Method 2
allowing the rough clad material to undergo anneal-heat treatment at a temperature falling within a range from −200° C. to −100° C. inclusive from a recrystallization temperature of the base material
Data Source
AI summary
The present invention is a clad material for an electric contact, including a base material composed of a Cu-based, precipitation-type age-hardening material, and a contact material composed of an Ag alloy bonded to the base material. On a bonded interface between the contact material and the base material, a width of a diffusion region including Ag and Cu is 2.0 μm or shorter. The clad material is produced by bonding each other the contact material and the base material having undergone solutionizing and age-hardening beforehand, suppressing the diffusion region from expanding after bonding. The present invention is capable of providing an electric contact, which achieves higher conductivity, without sacrificing property of the Cu-based, precipitation-type age-hardening material.