Pink Au Alloy Decorative Coating Hardness and Flaw Visibility

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Solution Overview

Problem

Pink Au alloy coating films used in decorative parts have low hardness and are brittle, leading to aesthetic issues as flaws are easily visible, and when thinner, the underlying dark layer with low brightness becomes apparent, compromising the sophisticated pink appearance.

Innovation Solution

A decorative part with a hardening layer comprising a base layer, a primary layer, and a finishing layer, where the primary layer is laminated between the base and finishing layers, comprising Au alloy layers with Hf, Ti, or Zr, and compound layers with nitrogen or carbon, and the finishing layer is an Au alloy with Cu and other metals, enhancing hardness and visibility of flaws.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the pink Au alloy coating film is made thicker (0.1 to 0.2 μm) to improve brightness and decorative appearance, then the brightness and pink color are enhanced, but flaws in the coating become deeper and more visible, spoiling the aesthetic appearance

Engineering Contradiction:
ImprovebrightnessVSAvoidflaw visibility
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent divides the coating structure into multiple layers: a base layer (Ti carbonitride, 0.5-1.0 μm) providing hardness and flaw resistance, and a finishing layer (pink Au alloy, 0.05-0.15 μm) providing brightness and decorative appearance. This segmentation allows each layer to optimize its function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses a composite coating structure combining Ti carbonitride (hard, flaw-resistant, dark pink) with Au alloy (soft, bright, decorative). The composite structure leverages the strengths of both materials while mitigating their individual weaknesses.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the pink Au alloy coating film is made thinner (smaller than 0.1 μm) to reduce flaw visibility, then flaws and peelings become less visible, but the dark lower layer with low brightness becomes visible, spoiling the sophisticated pink aesthetic appearance

Engineering Contradiction:
Improveflaw visibilityVSAvoidbrightness
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent divides the coating structure into multiple layers: a base layer (Ti carbonitride, 0.5-1.0 μm) providing hardness and flaw resistance, and a finishing layer (pink Au alloy, 0.05-0.15 μm) providing brightness and decorative appearance. This segmentation allows each layer to optimize its function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different material properties to different layers: the base layer has high hardness and flaw resistance but dark color, while the finishing layer has high brightness and decorative appearance. Each layer's properties are optimized for its specific function in the overall structure.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If a single-layer pink Au alloy coating is applied to achieve decorative appearance, then the process is simple, but the coating has low hardness and is brittle, making it prone to flaws and peelings

Engineering Contradiction:
Improvecoating process simplicityVSAvoidhardness
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent divides the coating structure into multiple layers: a base layer (Ti carbonitride, 0.5-1.0 μm) providing hardness and flaw resistance, and a finishing layer (pink Au alloy, 0.05-0.15 μm) providing brightness and decorative appearance. This segmentation allows each layer to optimize its function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses a composite coating structure combining Ti carbonitride (hard, flaw-resistant, dark pink) with Au alloy (soft, bright, decorative). The composite structure leverages the strengths of both materials while mitigating their individual weaknesses.

Inventive Principle:
Principle #40Composite materials

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 solution maintains a sophisticated pink aesthetic appearance by making flaws and peelings in the finishing layer hardly visible, even if they occur, through increased hardness and improved color tone matching, ensuring long-term use without compromising appearance.

Implementation Method 1

about 1 μm of a pink carbonitride is formed by an ion plating method

Methodology Applied
Scientific EffectIon plating: Physical Vapour Deposition

Implementation Method 2

0.1 μm of an Au-Pd alloy is formed by a wet plating method

Methodology Applied
Scientific EffectWet plating: Electroplating

Data Source

PatentEP2199429B1Decorative component
Publication Date: 2016.03.23 CITIZEN WATCH CO LTD
  • EP2199429B1 patent drawingFigure 1
  • EP2199429B1 patent drawingFigure 2
  • EP2199429B1 patent drawingFigure 3~4

AI summary

[Subject] In a decorative part having a pink Au alloy hard coating film, the sophisticated pink aesthetic appearance thereof can be maintained for long time use by making the decorative part that flaws or peelings are hardly visible even if flaws are caused in the coating film or the coating film is peeled off. [Means for solving Subject] The decorative part comprises a hardening layer having a pink Au alloy coating film on the surface wherein the hardening layer is obtainable by laminating a base layer, a primary layer and a finishing layer from the side of a substrate, the base layer comprises a metal layer comprising one metal or two or more metals selected from Hf, Ti and Zr and, superimposed thereon, a compound layer comprising the same metal constituting the metal layer and further comprising nitrogen, carbon or oxygen, the primary layer has a laminating structure such that an Au alloy layer, and a compound layer comprising one metal or two or more metals selected from Hf, Ti and Zr and further comprising nitrogen, carbon or oxygen are laminated one after the other, and the finishing layer comprises an Au alloy layer.