Coinage Cladding Alloy Composition for Vending Machine Compatibility

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Solution Overview

Problem

Current coinage materials, such as cupronickel alloys, face challenges in achieving the right balance of electrical conductivity, mechanical properties, and cost-effectiveness for use in currency applications, particularly in coins that need to function with vending machines and maintain appearance and durability.

Innovation Solution

A coinage cladding alloy comprising nickel (5-7 wt.%), zinc (21-29 wt.%), manganese (12-16 wt.%), and copper, with specific thermal processing to achieve electrical conductivity between 2-3% IACS and a disordered crystalline phase, allowing for tailored properties like hardness and color.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cupronickel alloys are used for coinage, then electrical conductivity and durability are improved, but cost increases

Engineering Contradiction:

ImprovedurabilityVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters by incorporating zinc (21-29 wt.%) and manganese (12-16 wt.%) along with nickel (5-7 wt.%) to achieve the desired electrical conductivity (2-3% IACS) without using expensive cupronickel alloys, thereby reducing cost while maintaining durability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite cladding alloy system with multiple elements (Cu-Ni-Zn-Mn) that combines the beneficial properties of different metals to achieve both cost-effectiveness and durability, replacing the more expensive cupronickel composition

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If electrical conductivity is increased for vending machine acceptance, then compatibility with vending machines improves, but material cost increases

Engineering Contradiction:

Improvevending machine acceptanceVSAvoidmaterial cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent optimizes the electrical conductivity parameter to fall within 2-3% IACS by adjusting the alloy composition (specifically nickel content at 5-7 wt.% and zinc at 21-29 wt.%), achieving sufficient vending machine acceptance without excessive cost

Inventive Principle:

Principle #35Parameter changes

3Reliability

If nickel content is increased to improve electrical conductivity, then vending machine compatibility improves, but manufacturing cost increases

Engineering Contradiction:

Improveelectrical conductivityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent carefully controls the nickel content parameter within 5-7 wt.% to achieve the required electrical conductivity range (2-3% IACS) while minimizing material cost, avoiding excessive nickel addition that would increase manufacturing cost

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite alloy system where zinc (21-29 wt.%) and manganese (12-16 wt.%) work synergistically with nickel to achieve the desired electrical conductivity at lower nickel content, reducing overall manufacturing cost

Inventive Principle:

Principle #40Composite materials

4Adaptability or versatility

If alloy composition is optimized for electrical conductivity, then vending machine acceptance improves, but color stability deteriorates

Engineering Contradiction:

Improvevending machine acceptanceVSAvoidcolor stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the alloy composition parameters (nickel 5-7 wt.%, zinc 21-29 wt.%, manganese 12-16 wt.%) to achieve electrical conductivity of 2-3% IACS while maintaining color stability through the specific balance of alloying elements that resist discoloration

Inventive Principle:

Principle #35Parameter changes

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 a cost-effective, durable, and conductive material suitable for currency applications, with improved acceptance in vending machines and resistance to discoloration and corrosion, offering a seamless substitution for existing cupronickel alloys.

Implementation Method 1

heating an alloying composition to a first temperature that is greater than or equal to an annealing temperature to form an annealing alloy

Methodology Applied

Scientific EffectAnnealing: Annealing

Implementation Method 2

quenching, by cooling the annealing alloy from the first temperature to a second temperature that is less than the annealing temperature

Methodology Applied

Scientific EffectQuenching: Heat Treatment

Data Source

PatentUS10513768B2Coinage cladding alloy and processing for making coinage cladding alloy

Publication Date: 2019.12.24 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES

AI summary

A coinage cladding alloy for coinage includes nickel present in an amount from 5 wt. % to 7 wt. %, based on a total weight of the coinage cladding alloy; zinc present in an amount from 21 wt. % to 29 wt. %, based on the total weight of the coinage cladding alloy; manganese present in an amount from 12 wt. % to 16 wt. %, based on a total weight of the coinage cladding alloy; copper; an electrical conductivity from 2% International Annealed Copper Standard (IACS) to 3% IACS; and a color comprising a yellowness vector b* that is from 2 to 10, based on a CIE L*a*b* color space and determined in accordance with ASTM Standard E308-15 (2015).