Rhenium-Tungsten Alloy Wire Surface Control for Discoloration-Free Storage
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Solution Overview
Problem
Rhenium-tungsten alloy wires undergo discoloration during storage, leading to changes in electrical resistance and mechanical properties, making them unsuitable for long-term use in applications like medical needles and probe pins, and requiring additional treatments that affect yield and usability.
Innovation Solution
Limiting the amount of NH4 ions on the wire surface to 10 massppm or less, achieved through surface treatment and storage conditions, prevents discoloration and ensures the wire's properties remain stable for extended storage periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ReW wire is stored in a sealed container under reduced pressure, then protection from external environment is improved, but discoloration still occurs with variations
Solution Approach 1:
The patent changes the chemical composition parameter by strictly controlling the NH4 content to 10 massppm or less. This compositional parameter change fundamentally alters the wire's resistance to discoloration, enabling long-term storage stability even without perfect environmental sealing.
Solution Approach 2:
The patent applies preliminary surface treatment during manufacturing to reduce NH4 content to 10 massppm or less before storage. This preliminary action prevents discoloration from occurring in the first place, making the wire inherently stable during storage without relying solely on environmental protection measures.
2Reliability
If additional treatment such as re-electrolysis is performed on discolored wire, then quality deterioration is addressed, but wire size changes and yield decreases
Solution Approach 1:
The patent applies preliminary anti-action by controlling NH4 content to 10 massppm or less during manufacturing, which prevents discoloration from occurring in the first place. This eliminates the need for subsequent corrective treatments like re-electrolysis, thereby maintaining wire dimensions and maximizing yield.
Solution Approach 2:
The patent converts the potential harm of NH4-induced discoloration into a benefit by establishing a precise control threshold (10 massppm or less). This transformation turns a quality risk into a reliable storage stability advantage, eliminating rework and maximizing productivity.
3Loss of time
If wire is stored for long periods, then production time is improved, but discoloration occurs and electrical resistance changes
Solution Approach 1:
The patent changes the chemical composition parameter by controlling NH4 content to 10 massppm or less, which fundamentally alters the wire's chemical stability. This parameter change enables the wire to maintain constant electrical resistance properties during long-term storage without discoloration.
Solution Approach 2:
The patent applies preliminary surface treatment during manufacturing to reduce NH4 content before storage. This preliminary action creates a stable wire that can be stored for extended periods without property changes, effectively decoupling storage duration from quality degradation.
4Reliability
If surface mixture layer is removed by electropolishing, then electrical resistance properties are improved, but NH4 remains on surface and causes later discoloration
Solution Approach 1:
The patent changes the surface composition parameter by controlling NH4 content to 10 massppm or less after electropolishing. This additional parameter control eliminates the harmful residue that would otherwise cause discoloration, complementing the benefits of electropolishing.
Solution Approach 2:
The patent applies a preliminary cleaning or treatment step after electropolishing to remove NH4 from the surface. This preliminary action prevents future discoloration while preserving the electrical resistance improvements achieved through electropolishing.
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
Preventing discoloration allows for long-term storage and improved yield of rhenium-tungsten alloy wires, maintaining their mechanical and electrical properties, thus enhancing their suitability for medical needles and probe pins.
Implementation Method 1
the surface becomes discolored to, for example, blue, yellow, red purple, or the like as the storage period becomes longer
Implementation Method 2
the surface mixture layer generated in a manufacturing step is removed by electropolishing
Data Source
AI summary
According to one embodiment, a rhenium-tungsten alloy wire is a wire made of a tungsten alloy containing rhenium. The amount of NH4 at a wire surface is 10 massppm or less, and is according to a ratio of a weight of NH4 ions at a wire surface to a weight of an alloy wire (a weight of NH4 ions at a wire surface/a weight of an alloy wire). According to the embodiment, a medical needle and a probe pin include the rhenium-tungsten alloy wire according to the embodiment.