Hydrogen-Ceramic Passivation for Stronger Watch Glass Components
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Solution Overview
Problem
Existing glass components, particularly those used in micromechanical and watchmaking applications, suffer from defects such as scratches, microcracks, and moisture ingress, which lead to slow crack propagation and reduced mechanical performance, especially when miniaturized.
Innovation Solution
Application of a thin passivation layer comprising refractory ceramics with at least 1% atomic hydrogen on the glass substrate surface to reduce defect density and isolate the component from ambient moisture, enhancing mechanical strength and fracture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the component size is reduced to exploit the performance of glassy silica, then the probability of millimetric defects is reduced, but the surface-to-volume ratio increases and slow crack propagation becomes more significant
Solution Approach 1:
The patent applies a passivation layer with specific thickness parameters (50-500 nm) to change the surface properties of the glass component. This parameter change prevents moisture ingress and reduces surface defect density, thereby improving resistance to slow crack propagation while maintaining the miniaturized component size
Solution Approach 2:
The passivation layer acts as an intermediary between the glass substrate and the ambient environment. It mediates the interaction by providing a protective barrier that prevents OH-ions from attacking the glass surface, thus reducing slow crack propagation without affecting the component's mechanical performance
2Strength
If a passivation layer is applied to reduce surface defects and prevent moisture ingress, then mechanical performance is improved, but component complexity increases
Solution Approach 1:
The passivation layer uses controlled thickness parameters (50-500 nm) to achieve effective protection without excessive complexity. This parameter optimization ensures the layer is thin enough to maintain component simplicity while thick enough to provide effective moisture barrier and defect reduction
Solution Approach 2:
The patent creates a composite structure by combining the glass substrate with a passivation layer of refractory ceramic material containing hydrogen. This composite approach provides enhanced fracture resistance through the synergistic combination of materials, where the passivation layer specifically addresses surface defects and moisture protection
3Object-affected harmful factors
If conventional coatings such as kerosene or polymer coatings are applied to limit humidity ingress, then moisture protection is improved, but tribological performance deteriorates
Solution Approach 1:
The patent uses a composite material approach by incorporating hydrogen-containing refractory ceramic in the passivation layer. This material combination provides both moisture barrier properties (protecting against humidity ingress) and maintains tribological performance, unlike conventional organic coatings that degrade under mechanical stress
Solution Approach 2:
The passivation layer uses specific material composition parameters (refractory ceramic with hydrogen content) and thickness parameters (50-500 nm) to achieve dual functionality: effective moisture protection and maintained tribological performance. The inorganic nature of the material ensures compatibility with mechanical contact requirements
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 passivation layer improves the mechanical performance of glass components by reducing surface defects and preventing moisture ingress, resulting in enhanced fracture toughness and resistance to failure.
Implementation Method 1
a passivation layer, directly in contact with the surface of the substrate and having a thickness of less than 1000 nm... The passivation layer comprises a refractory ceramic comprising at least 1% atomic hydrogen... so as to reduce the surface density of defects
Implementation Method 2
isolate the component from moisture (OH-ions) of atmospheric origin, which is responsible for accelerating the propagation of cracks
Data Source
AI summary
A timepiece component with improved tensile strength, the component comprising a substrate made of glass that is transparent to visible light and having a lateral dimension of approximately a few centimetres or less and a thickness of approximately 5 millimetres or less. The substrate is coated with a passivation layer directly in contact with the surface of the substrate having a thickness of less than 1000 nm. The passivation layer comprises a refractory ceramic comprising at least 1 at. % hydrogen. The present invention also relates to a method for manufacturing this component.