White Precious Metal Alloy for Jewelry Casting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current precious metal alloys for white jewelry, such as platinum, white gold, and silver, face challenges including high melting points, rapid solidification, high costs, corrosion issues, and aesthetic problems like yellow tint and nickel allergies, limiting their efficiency and appeal in jewelry manufacturing.
Innovation Solution
A precious metal alloy comprising 40-55% silver, 15-35% palladium, 15-25% copper, up to 3% zinc or silicon, and up to 1% iridium or ruthenium, which provides a white color, slow solidification, resistance to tarnishing, and can be age hardened for increased strength, allowing for efficient casting and traditional jewelry working methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum is used to make white jewelry pieces, then excellent luster and corrosion resistance are achieved, but the high melting point and rapid solidification rate significantly reduce manufacturing efficiency
Solution Approach 1:
The patent creates a composite alloy system combining platinum (30-40%) with lower melting point precious metals (gold, silver, palladium) and base metals (copper, nickel, zinc). This composite approach maintains the corrosion resistance of platinum while the other components lower the overall melting point and extend solidification time, enabling more efficient investment casting processes
Solution Approach 2:
The patent systematically varies the composition parameters of the alloy, specifically adjusting the ratios of platinum to other metals to achieve an optimal balance between corrosion resistance and melting characteristics. By changing the chemical composition parameters, the alloy achieves a melting point range and solidification rate suitable for traditional jewelry manufacturing processes
2Productivity
If white gold alloy is used to achieve white color, then casting efficiency is improved, but yellow tint and nickel allergies occur
Solution Approach 1:
The patent applies local quality by selectively using different metal components for different functions: platinum and palladium provide the white color and corrosion resistance, while copper and zinc contribute to casting efficiency. This functional distribution within the alloy allows achieving white appearance without relying on nickel, eliminating allergy concerns while maintaining good casting properties
Solution Approach 2:
The patent replaces expensive and problematic nickel with more affordable and safer alternatives like copper and zinc, which provide similar casting efficiency benefits without causing allergies or yellow tint. This substitution uses cheaper, shorter-lived aesthetic properties that can be maintained through proper alloy design
3Quantity of substance
If silver is used for white jewelry, then cost is reduced, but tarnishing resistance is poor
Solution Approach 1:
The patent creates a protective composite structure where platinum (30-40%) and palladium (10-20%) form a corrosion-resistant matrix that protects the more reactive but cost-effective silver (10-30%) and copper (10-20%) components from tarnishing. This composite approach allows using cheaper metals while the precious metal framework provides the necessary protection against oxidation and tarnishing
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 achieves a white color comparable to platinum, slow solidification like white gold, and high resistance to tarnishing, enabling the production of jewelry with improved durability and aesthetic appeal without the need for rhodium plating or nickel, while being cost-effective and suitable for various jewelry pieces.
Implementation Method 1
the alloy... has a relatively slow solidification time when poured from a molten state
Implementation Method 2
that can be age hardened to at least about 240 Vickers, and whose yield point can be substantially strengthened via age hardening
Data Source
AI summary
Jewelry articles made from a precious metal alloy having a color that is substantially white and comparable to that of platinum alloys, having liquidus and solidus temperatures comparable to that of white gold alloys, having a relatively slow solidification time when poured from a molten state, having substantial resistance to tarnishing under conditions normally encountered during ordinary human wear, having a cast hardness of about 140 Vickers, and that can be age hardened to at least about 240 Vickers, and whose yield point can be substantially strengthened via age hardening. The preferred composition of the alloy is about forty to fifty-five percent by weight silver; about fifteen to thirty-five percent by weight palladium; about fifteen to twenty-five percent by weight copper; and up to about three percent by weight zinc and/or silicon and up to about one percent by weight of a grain refiner such as iridium and/or ruthenium.