Silicon Intermediate Coating for Silver Glazing Durability
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Solution Overview
Problem
Silver-based functional metal layers in glazings used for heating and cooling devices suffer from insufficient chemical and thermal resistance, leading to defects such as corrosion, scratches, and dewetting, which degrade their energy and optical performance, especially under high-temperature and humid conditions.
Innovation Solution
A transparent substrate coated with a stack comprising a silver-based functional metal layer sandwiched between dielectric coatings, with an intermediate silicon-based coating in contact with the substrate, composed of different chemical elements or varying proportions, enhancing chemical durability and resistance to heat treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a silver-based functional metal layer is used to reduce emissivity and improve thermal reflection, then the energy performance is improved, but the chemical and thermal resistance deteriorates, leading to corrosion and degradation under high-temperature and humid conditions
Solution Approach 1:
A silicon-based intermediate layer is introduced between the silver functional layer and the dielectric coating/substrate. This intermediary layer acts as a protective barrier that prevents direct contact between the silver and the corrosive environment, while also providing thermal stability during heat treatments. The silicon layer has appropriate thermal expansion properties that reduce stress on the silver layer during thermal cycling, thereby preventing dewetting and corrosion while maintaining the low-emissivity performance.
Solution Approach 2:
The patent creates a composite structure consisting of multiple layers: the silver-based functional layer, the silicon-based intermediate layer, and dielectric coatings. This composite material system combines the low-emissivity properties of silver with the thermal and chemical stability of silicon and dielectric materials, achieving both energy efficiency and reliability under extreme conditions.
2Reliability
If the silver layer is subjected to high-temperature heat treatments to improve durability, then the thermal resistance is improved, but the mechanical strength deteriorates, causing dewetting and structural degradation
Solution Approach 1:
The silicon-based intermediate layer is deposited beforehand to provide a stable substrate for the silver layer before heat treatment. This preliminary protective structure prevents the silver layer from dewetting during subsequent high-temperature processes such as tempering or bending, as the silicon layer has appropriate wetting properties and thermal expansion characteristics that maintain adhesion under thermal stress.
Solution Approach 2:
The patent modifies the thermal and mechanical parameters of the substrate by introducing the silicon intermediate layer, which has different thermal expansion properties compared to the original substrate. This parameter change reduces thermal stress on the silver layer during heat treatments, preventing mechanical degradation while allowing the necessary thermal resistance to be achieved.
3Reliability
If dielectric coatings are added to protect the silver layer from chemical attacks, then the chemical durability is improved, but the manufacturing complexity increases due to multiple layer deposition
Solution Approach 1:
The patent combines the protective function and the intermediate layer function into a single silicon-based layer. This merged layer simultaneously provides chemical protection against corrosion, thermal stability during heat treatments, and mechanical support to prevent dewetting, thereby reducing the total number of layers compared to separate protective coatings while maintaining or improving overall performance.
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 intermediate silicon-based coating significantly improves the thermal resistance and delays degradation, allowing the material to withstand high-temperature heat treatments without haze or emissivity loss, ensuring robustness during tempering and bending processes, and maintaining chemical durability.
Implementation Method 1
Silver-based functional metal layers (or silver layers) have advantageous properties of electrical conduction and of reflection of infrared radiation (IR)
Implementation Method 2
The intermediate coating makes it possible to delay the degradation of a functional coating. Nevertheless, in order for this delayed degradation to be sufficient not to lead to degradation during a high-temperature heat treatment
Data Source
AI summary
A material includes a transparent substrate coated with a stack including at least one silver-based functional metal layer and at least two dielectric coatings, each dielectric coating including at least one dielectric layer, so that each functional metal layer is placed between two dielectric coatings, wherein the dielectric coating located in contact with the substrate includes an intermediate coating including two different layers containing silicon, the two layers containing silicon consist of different chemical elements or composed of the same elements in different proportions.