Ballpoint Pen Refill Tip Using Copper-Zinc Alloy with Silicides
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Solution Overview
Problem
Existing ballpoint pen refills face challenges in achieving a balance of strength, temperature resistance, wear resistance, and toughness while maintaining environmental compatibility, particularly due to limitations in materials like nickel silver alloys used for writing tips.
Innovation Solution
A copper-zinc alloy with embedded iron-nickel-manganese-containing mixed silicides, produced through continuous or semi-continuous casting, offering high hardness and strength with sufficient ductility, and featuring a combination of β-phase and α-phase structures for enhanced wear and temperature resistance, along with corrosion resistance and cold forming capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If nickel silver alloy is used for writing tip, then aesthetic quality is improved, but wear resistance and temperature resistance are insufficient
Solution Approach 1:
The patent uses a composite material consisting of copper-zinc alloy matrix with embedded iron-nickel-manganese-containing mixed silicides. This composite structure provides both the aesthetic appearance needed for writing instruments and the enhanced wear resistance and temperature resistance through the hard silicide phases distributed throughout the matrix.
Solution Approach 2:
The patent changes the material parameters by specifying precise compositional ranges: 28.0-36.0% Zn, 0.5-1.5% Si, 1.5-2.5% Mn, 0.2-1.0% Ni, 0.5-1.5% Al, 0.1-1.0% Fe, with optional additions of Pb, Sn, P, and S. These parameter changes create an optimized balance between aesthetics, wear resistance, and temperature resistance.
2Strength
If copper-zinc alloy with high strength is used, then wear resistance is improved, but ductility decreases
Solution Approach 1:
The patent applies local quality by creating a non-uniform microstructure with hard silicide phases (iron-nickel-manganese-containing mixed silicides) embedded in a softer copper-zinc alloy matrix. The hard phases provide wear resistance at critical contact points, while the softer matrix maintains overall ductility and toughness of the component.
Solution Approach 2:
The composite structure of hard silicide particles in a ductile copper-zinc matrix allows the material to exhibit both high wear resistance from the silicides and sufficient ductility from the metal matrix, resolving the contradiction between strength and formability.
3Ease of manufacture
If lead content is increased for ease of manufacture, then cold forming capability is improved, but environmental compatibility worsens
Solution Approach 1:
The patent optimizes the lead content parameter within strict limits (maximum 0.2% Pb) while compensating for reduced lead with optimized combinations of other elements including Zn (28.0-36.0%), Al (0.5-1.5%), and Si (0.5-1.5%). This parameter optimization maintains adequate cold forming capability while significantly reducing environmental harm from lead.
Solution Approach 2:
The patent replaces toxic lead with more environmentally friendly elements, accepting that the material may have slightly reduced recyclability or lifespan, thereby prioritizing environmental compatibility while maintaining functional performance through the optimized copper-zinc-silicon-manganese alloy system.
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 alloy provides improved mechanical and thermal properties, including increased tensile strength, hardness, and wear resistance, while ensuring environmental compatibility by minimizing lead content and maintaining necessary ductility for effective use in ballpoint pen refills.
Implementation Method 1
the alloy has a high proportion of hard phases, which contributes to improving the material's resistance to abrasive wear in conjunction with the lead ball as a friction pairing
Implementation Method 2
which can be produced using the continuous or semi-continuous continuous casting process
Implementation Method 3
The alloy has high hardness and strength values, but still ensures a necessary level of ductility, expressed by the elongation at break in a tensile test. With this combination of properties, the subject matter of the invention is particularly suitable for use in a ballpoint pen refill.
Data Source
AI summary
The invention relates to a refill for a ball-point pen, comprising an ink cartridge and a ball, said ball being arranged in a writing tip provided at the front end of the ink cartridge, wherein at least the writing tip of the ink cartridge consists of a copper-zinc alloy of the following composition (wt. %): 28.0 to 36.0% Zn, 0.5 to 1.5% Si, 1.5 to 2.5% Mn, 0.2 to 1.0% Ni, 0.5 to 1.5% Al, 0.1 to 1.0% Fe, optionally also up to a maximum of 0.1% Pb, optionally also up to a maximum of 0.2% Sn, optionally also up to a maximum of 0.1% P, optionally also up to a maximum of 0,08 % S, the rest being Cu and inevitable impurities, with mixed silicides containing iron, nickel and manganese being embedded in the matrix.