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Key Control Points for Silver‑Plated Copper‑Foil Flexible‑Connection Diffusion‑Welding
Sep 22,2026
Silver‑plated copper‑foil flexible‑connections are important conductive accessories for high‑current electrical equipment, which are manufactured by diffusion‑welding of multi‑layer silver‑plated copper‑foils. During diffusion‑welding, improper parameter setting will easily lead to silver‑layer peeling, inter‑layer delamination, insufficient diffusion bonding, surface silver‑layer ablation and unstable resistance.
I Process Difficulties of Silver‑Plated Copper‑Foil Diffusion‑Welding
1.Silver‑plated layer is thin; excessive temperature or pressure will cause silver‑layer squeezing‑off, ablation and peeling. Insufficient temperature and pressure will result in poor atomic diffusion and inter‑layer delamination.
2.Multi‑layer stacking exists; air is easy to be trapped between foil layers. If gas cannot be fully exhausted, inter‑layer bubbles and hollow defects will generate.
3.Silver‑copper bimetallic interface is easy to form brittle intermetallic compounds. Excessive holding time at high temperature will make compound layer thicken and reduce flexibility and mechanical performance of flexible‑connection.
4.Surface residual oil, oxide and dust will hinder diffusion bonding and become hidden defect sources.
II Core Control Points of Diffusion‑Welding Process
1.Pre‑weld cleaning control: Completely remove oil stain, oxide and dust on silver‑plated copper‑foil surfaces; protect silver‑plated layer to prevent scratch before stacking.
2.Stacking process control: Neatly stack each layer of silver‑plated copper‑foil, reduce inter‑layer gaps, avoid foil offset and local suspension.
3.Temperature‑parameter control: Adopt reasonable temperature‑rise gradient, strictly control peak temperature; prevent silver‑layer melting‑ablation and brittle intermetallic‑phase over‑growth.
4.Pressure‑parameter control: Match pressure value according to foil thickness and layer‑count; pressure shall be enough to realize close contact between layers, but cannot squeeze out silver‑plated layer.
5.Holding‑time control: Reasonably set high‑temperature holding‑time; guarantee sufficient atomic diffusion, meanwhile avoid excessive brittle‑phase thickening.
6.Post‑weld cooling‑process control: Execute slow cooling under pressure after welding; avoid rapid cooling‑induced residual stress, peeling and micro‑crack defects.
III Common Defects and Countermeasures
1.Silver‑layer peeling / silver‑layer loss: Too high temperature, excessive pressure, scratch before stacking.
Countermeasure: Lower peak temperature, reduce forming pressure, strengthen pre‑stacking surface protection.
2.Inter‑layer delamination and hollowing: Incomplete air exhaust, insufficient temperature / pressure, foil offset and local suspension.
Countermeasure: Optimize staged pre‑pressing for gas exhaust; raise temperature‑pressure properly; standardize stacking operation.
3.Over‑large intermetallic compound layer, product brittle fracture: Over‑long high‑temperature holding‑time.
Countermeasure: Shorten high‑temperature holding‑time, optimize temperature‑rise curve.
4.Unstable resistance and local high‑resistance point: Surface impurity residue, incomplete diffusion bonding, local silver‑layer damage.
Countermeasure: Strengthen pre‑weld cleaning; optimize diffusion parameters; protect silver‑plated layer in whole‑process operation.
Wuxi Haifei Intelligent Equipment Co., Ltd. https://www.haifeiwelder.com/
Wuxi Haifei Intelligent Equipment Co., Ltd. has been focusing on the R&D and production of spot‑welding machines for 17 years. The company has obtained ISO9001 Quality Management System Certification, China Compulsory Certification (3C) and CE Certification. It is a National High‑tech Enterprise, a Specialized, Refined, Differential and Innovative Enterprise of Jiangsu Province, a Specialized, Refined, Differential and Innovative Enterprise of Wuxi, and a Gazelle Enterprise in the Southern Jiangsu National Self‑Dependent Innovation Demonstration Zone.
Should you be interested in our spot‑welding machines, please contact us: 400‑0510‑750.
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Wuxi HAIFEI Intelligent Equipment Co., Ltd.
Wuxi HAIFEI Welding Equipment Co., Ltd.
Add: 28 Shuiyun Road, Yuecheng, Jiangyin, Jiangsu Province, China. (Postal Code: 214404)
Mobile: +86 18915302352
Email: wushijie@jshaifei.com