Black Gold Material via Gold Nanoparticle Titanium Dioxide Matrix

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Solution Overview

Problem

Current methods for achieving a black or anthracite color in gold materials fail to produce a coloration that is uniform throughout the material, as they result in superficial colored layers or nanostructures that degrade quickly, limiting their applications.

Innovation Solution

A process involving the assembly of gold nanoparticles in a titanium dioxide matrix, where a mixture of gold and titanium dioxide precursors is heated with a hydrazine compound to form a suspension of gold particles coated with titanium dioxide, followed by filtration and sintering to create a compact, black or anthracite-colored material with a gold content greater than 18 carats.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional coating or surface treatment methods are used to achieve black or anthracite color in gold, then the coloring is applied to the surface, but the coloration is not uniform throughout the material and the surface layer may degrade

Engineering Contradiction:
Improveuniformity of colorationVSAvoiddurability of colored layer
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention incorporates color-generating nanoparticles (gold, silver, or their alloys) and coloring agents into the base material before final formation, ensuring uniform distribution throughout the bulk material rather than applying color superficially. This preliminary incorporation of coloring components resolves the contradiction by achieving both uniform coloration and durability simultaneously.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention creates a composite material structure where nanoparticles and coloring agents are integrated within the base material matrix. This composite approach allows the color to be distributed uniformly throughout the material while the matrix provides structural support and durability, resolving the contradiction between uniform coloration and layer stability.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If laser nanostructuring is used to create black color on gold surface, then surface coloring is achieved, but the nanostructure degrades rapidly limiting applications

Engineering Contradiction:
Improvesurface coloring capabilityVSAvoidstability of nanostructure
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Instead of creating unstable surface nanostructures through laser treatment, the invention preliminarily incorporates stable nanoparticles and coloring agents into the material bulk during manufacturing. This approach achieves surface coloring capability through uniform bulk coloration while avoiding the creation of degraded nanostructures, resolving the contradiction between ease of manufacture and structural stability.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If gold alloys with alloying metals are used to achieve different colors, then color variety is obtained, but the gold content may be reduced below 18 carats

Engineering Contradiction:
Improvecolor varietyVSAvoidgold content
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The invention uses nanoparticles and coloring agents as localized color sources distributed throughout the gold matrix, rather than relying on bulk alloying. This allows different colors to be achieved through selective placement and composition of nanoparticles while maintaining the bulk gold content above 18 carats, resolving the contradiction between color variety and gold content.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention creates a composite structure where gold serves as the continuous matrix maintaining high gold content, while dispersed nanoparticles and coloring agents provide color variety. This composite approach enables versatile color options without compromising the quantity of gold, as the coloring components are present as discrete phases rather than replacing gold atoms.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If electrodeposition or CVD processes are used to coat gold with rhodium, ruthenium, or carbon, then black or anthracite color is achieved, but only a superficial colored layer is formed

Engineering Contradiction:
Improvecolor application processVSAvoidthroughout coloration
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention incorporates coloring components into the base material during the manufacturing process itself, rather than applying color superficially through subsequent coating operations. This preliminary incorporation ensures uniform coloration throughout the material while maintaining ease of manufacture through integration into the base material formation process.

Inventive Principle:
Principle #10Preliminary action

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

This method enables the production of a composite material with a high gold content that is uniformly colored throughout, offering improved durability and versatility for luxury and cosmetic applications.

Implementation Method 1

heating the mixture to a first temperature so as to reduce the gold precursor and form the titanium dioxide matrix

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 2

adding a hydrazine compound to the mixture. After the addition of the hydrazine compound, the mixture is heated to the first temperature, the heating step being combined with stirring, so as to obtain a suspension formed by the gold particles coated with titanium dioxide

Methodology Applied
Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 3

The powder is then compacted by a sintering process

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3482851B1Method of manufacturing a black or anthracite colour material comprising at least 18 gold carats
Publication Date: 2023.08.30 CARTIER INTERNATIONAL AG
  • EP3482851B1 patent drawingFigure 1A~1B

AI summary

A process for manufacturing a black or anthracite colored material comprising at least 18 carats of gold, formed from an assembly of gold nanoparticles in a titanium dioxide matrix; the process comprising the steps of: providing in a reactor a mixture comprising a gold precursor, a titanium dioxide precursor, and a solvent including water, an alcoholic solvent, and a polar aprotic solvent; heating the mixture to a first temperature (T1) so as to reduce the gold precursor and form the titanium dioxide matrix; once the mixture has reached the first temperature (T1), adding a hydrazine compound to the mixture; and after reaction of the hydrazine compound with the mixture, separating said material.