Ceramic Watch Component Multi-Color Manufacturing
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Solution Overview
Problem
Zirconia-based ceramics used in watchmaking are inherently white and challenging to color, particularly in achieving uniform and reproducible multi-colors like red and black, which complicates the manufacturing process and limits design options.
Innovation Solution
A process involving the creation of a green body from ceria-zirconia, partial debinding, local impregnation with metal salts, and heat treatment under reducing atmospheres to achieve a two-tone or multicolored ceramic component with specific color control, ensuring high mechanical properties and aesthetic appeal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If colouring pigments are used to colour zirconia-based ceramics, then the ceramic can be coloured, but the manufacturing process becomes complicated and certain colours (especially combinations like red and black) cannot be obtained
Solution Approach 1:
The invention changes the chemical parameters of the ceramic composition by incorporating cerium oxide (3-6 wt%) alongside zirconia, and modifies the thermal processing parameters by implementing a two-stage heat treatment: first oxidation at 1400-1650°C to form the red color, then reduction at 1200-1550°C to create the black color. This allows complex multi-color effects to be achieved through controlled parameter changes rather than complex manufacturing processes.
Solution Approach 2:
The invention uses a composite ceramic material system combining zirconia (providing mechanical strength and white base color) with cerium oxide (providing red coloration when oxidized and black when reduced). This composite approach enables multiple colors to be achieved in a single material system through controlled thermal processing, eliminating the need for separate coloring steps.
2Adaptability or versatility
If conventional colouring methods are used, then the ceramic can be coloured, but the colour is not uniform, predictable and reproducible
Solution Approach 1:
The invention achieves uniform and reproducible colors by precisely controlling thermal processing parameters. The oxidation step at 1400-1650°C in oxygen-rich atmosphere ensures consistent red coloration, while the subsequent reduction step at 1200-1550°C in hydrogen or carbon monoxide atmosphere produces uniform black. These controlled parameter changes ensure that the same colors can be reproduced consistently across different batches.
Solution Approach 2:
The invention employs continuous heat treatment processes where the ceramic piece is continuously exposed to controlled atmospheric conditions (oxidation followed by reduction) without interruption. This continuous processing ensures uniform color penetration throughout the material and eliminates the variability introduced by intermittent or discontinuous coloring methods.
3Strength
If zirconia-based ceramic is used, then high mechanical properties are achieved, but the ceramic is naturally white and difficult to colour
Solution Approach 1:
The invention creates a composite ceramic system where zirconia (providing high mechanical strength and structural integrity) is combined with cerium oxide (providing coloration capability). The zirconia-ceria composite maintains the excellent mechanical properties of zirconia while adding the versatility to produce red and black colors through controlled oxidation and reduction treatments, respectively.
Solution Approach 2:
The invention utilizes reversible color changes of cerium oxide based on oxidation-reduction reactions. In the oxidizing atmosphere during the first heat treatment, cerium oxide forms red-colored compounds. During the second reduction treatment, the same cerium oxide transforms to produce black color. This allows the same material to exhibit different colors without changing the base zirconia structure or mechanical properties.
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 process allows for the production of ceramic timepiece components with reliable, reproducible, and aesthetically pleasing multi-colors, such as red and black, while maintaining high mechanical properties, and ensures color consistency even with surface wear.
Implementation Method 1
sintering and thermally treating the impregnated debound intermediate component by at least one step of heat treatment under a reducing atmosphere
Implementation Method 2
heat treatment under a reducing atmosphere
Data Source
AI summary
The process for manufacturing a ceramic timepiece component includes:—manufacturing an intermediate component (E1) in the form of green body based on ceria-zirconia;—totally or partially debinding (E2) the intermediate component to obtain a debound intermediate component:—partially impregnating (E3) the debound intermediate component with at least one solution comprising at least one metal salt, on one portion only of its surface, to obtain an impregnated debound intermediate component:—sintering and thermally treating (E4) the impregnated debound intermediate component by performing at least one heat treatment under a reducing atmosphere (E42; E41′).