Nickel-Iron Alloy Electroplating for Watch Springs
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Solution Overview
Problem
Existing methods for manufacturing watch components by electroforming, such as nickel springs, face challenges with internal stresses leading to creep and relaxation issues, which affect the reliability of the components over time, and introducing ferromagnetic elements to improve properties is not suitable for watchmaking applications.
Innovation Solution
A process involving an electrolytic bath with a nickel-based alloy containing phosphorus or other elements like Boron, Bismuth, and Chlorine, combined with a heat treatment step, to achieve stable elastic properties and reduce internal stresses, resulting in a reliable component suitable for watchmaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If nickel is used to manufacture watch components by electroforming, then good elastic properties are obtained, but internal stresses cause creep and relaxation issues reducing reliability over time
Solution Approach 1:
The invention changes the chemical composition parameters of the nickel alloy by adding controlled amounts of iron (1-30% by weight) and sulfur (0.005-0.2% by weight) to modify the material properties. This alters the crystal lattice structure through solid solution strengthening, which changes the stress-relaxation behavior and reduces creep while maintaining elastic properties
Solution Approach 2:
The invention creates a composite nickel alloy system combining nickel with iron and sulfur elements. The iron interferes in solid solution randomly in the crystal lattice of the nickel, causing distortion that improves mechanical behavior, while sulfur provides additional strengthening. This multi-element composite approach resolves the contradiction between maintaining elasticity and preventing time-dependent degradation
2Reliability
If iron is added to nickel alloy to improve component behavior, then creep and relaxation resistance are enhanced, but magnetic susceptibility increases which is not suitable for watchmaking
Solution Approach 1:
The invention precisely controls the iron content parameter within 1-30% by weight and sulfur content within 0.005-0.2% by weight to achieve the optimal balance. By limiting iron to a controlled range and adding sulfur, the alloy gains creep resistance while the magnetic properties remain acceptable for watchmaking applications
Solution Approach 2:
The invention applies local quality by introducing sulfur at specific low concentrations (0.005-0.2% by weight) to provide localized strengthening without significantly affecting the overall magnetic properties. The sulfur distributes throughout the nickel-iron matrix to provide dispersion strengthening while maintaining the non-magnetic characteristics required for watch components
3Strength
If greater thickness of material is deposited to improve component strength, then mechanical properties are enhanced, but internal stresses and cracking resistance are worsened
Solution Approach 1:
The invention changes the material composition parameters by adding iron and sulfur to the nickel alloy, which modifies the stress distribution and internal stress levels within the deposited material. This compositional change allows thicker deposits to be formed without proportionally increasing internal stresses, thereby maintaining cracking resistance while achieving the desired thickness for mechanical 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 process enhances the stability and reliability of watch components by minimizing creep and relaxation phenomena, ensuring consistent performance under mechanical stress and extending the lifespan of the components.
Implementation Method 1
The invention is based on a process for manufacturing a watch component, characterized in that it comprises an electroplating step consisting in depositing an alloy on a substrate
Implementation Method 2
combined with a heat treatment step, to achieve stable elastic properties and reduce internal stresses
Data Source
Figure 1~3
AI summary
A method for manufacturing a watch component, characterized in that it comprises an electrodeposition step consisting of depositing an alloy on a substrate, forming at least one side of the watch component with a thickness greater than or equal to 50 microns, this electrodeposition step being carried out from an electrolytic bath comprising a compound containing nickel and a second compound without nickel, in proportions such that the alloy obtained comprises a nickel content by weight of between 91% and 99.8% inclusive and between 0.2% and 6% inclusive, or even between 0.2% and 4% inclusive by weight of a second element from the second compound.