Partial Gold Plating of Metal Packaging Housings
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Solution Overview
Problem
Current partial gold plating methods for metal packaging housings face instability and high manufacturing costs, particularly due to the use of electroless nickel plating, which can lead to gold layer displacement and increased stress, affecting solderability and reliability.
Innovation Solution
A method involving nickel plating, oxidation, gold plating, and reduction processes to form a partial gold layer on the housing lead, where the nickel-plated base is used as an anode in an alkaline solution to form an oxide film, reducing the rate of gold layer displacement and improving stability, while avoiding electroless nickel plating to reduce costs and enhance bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroless nickel plating is used for partial gold plating of housing lead, then gold layer displacement is prevented through similar electrode potential, but process stability deteriorates and gold withdrawal becomes necessary
Solution Approach 1:
The patent extracts the problematic electroless nickel plating step and replaces it with electroplating methods. By removing the electroless plating process, the patent eliminates the need for subsequent gold withdrawal operations while maintaining gold layer stability through controlled electroplating parameters and protective oxide layer formation on the base.
Solution Approach 2:
The patent changes the plating method from electroless to electroplating, fundamentally altering the deposition mechanism. By controlling electroplating parameters such as current density, electrolyte composition, and adding oxide formation steps, the patent achieves stable gold layer adhesion without requiring gold withdrawal, thus improving process stability.
2Reliability
If electroless nickel plating layer is applied on housing lead, then gold layer replacement is prevented, but plating layer stress increases reducing bending times
Solution Approach 1:
The patent removes the electroless nickel plating layer entirely and replaces it with electroplated nickel layers. This extraction eliminates the stress-induced brittleness problem while maintaining gold layer protection through alternative electroplating and oxide formation mechanisms that do not compromise lead flexibility.
Solution Approach 2:
The patent employs a composite plating structure consisting of electroplated nickel layers combined with oxide formation on the base. This composite approach provides both gold layer stability and maintains lead ductility, avoiding the stress concentration and brittleness issues associated with electroless nickel plating.
3Reliability
If thin layer of gold is buried on base to prevent replacement, then gold displacement is prevented, but production cost increases
Solution Approach 1:
The patent extracts the buried gold layer approach and replaces it with electroplated nickel and oxide formation on the base. This elimination of buried gold reduces material costs significantly while maintaining effective gold layer protection through the electroplated nickel barrier and oxide layer that prevent gold displacement.
Solution Approach 2:
The patent uses inexpensive electroplated nickel and oxide layers instead of expensive buried gold. These cheaper alternative materials provide equivalent or superior protection against gold displacement while dramatically reducing production costs, aligning with the principle of using cost-effective substitutes.
4Ease of manufacture
If base is gold-plated for soldering, then solderability is improved, but gold brittleness occurs after long-term use
Solution Approach 1:
The patent applies gold plating selectively only to the housing lead where bonding strength and solderability are critical, while the base receives electroplated nickel and oxide treatment. This localized quality approach ensures solderability where needed without subjecting the entire base to gold plating, thereby preventing gold brittleness development in the base while maintaining excellent soldering performance on the lead.
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 method stabilizes the gold plating layer, reduces manufacturing costs, and improves the reliability and bending resistance of the packaging housing, allowing for effective laser welding and capping without the need for a buried gold layer, thus enhancing the packaging's overall performance.
Implementation Method 1
powering off the housing lead, powering on the base and place the base in an alkaline solution for oxidation to form an oxide layer on a surface of the nickel layer covering the base
Implementation Method 2
placing the packaging housing in a high temperature environment, and obtaining a partial gold-plated packaging housing by reducing the oxide layer on the surface of the nickel layer of the base using reducing gas
Implementation Method 3
forming a gold layer on a surface of the housing lead by performing gold plating on the housing lead
Data Source
AI summary
The present disclosure involves a method for partial gold plating of a metal packaging housing and a packaging housing thereof. The packaging housing may include a base. The base may be provided with at least one lead hole. A housing lead may be interspersed in the lead hole. The lead hole may be also provided with an insulator surrounding the housing lead. The method may include operations such as nickel plating, oxidation, gold plating, reduction, etc.