Zinc-Based Metallic Layer in Silver Glazing Coatings
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Solution Overview
Problem
Silver-based functional metallic layers in glazings undergo deterioration in resistivity and optical properties due to species migration during high-temperature heat treatments, which affects scratch resistance and corrosion resistance, particularly when certain blocking and dielectric layers are used.
Innovation Solution
Incorporating a zinc-based metallic layer separated by intermediate oxide layers, such as zinc oxide or titanium oxide, to control the diffusion of metallic zinc elements and enhance scratch resistance and corrosion resistance without significantly deteriorating resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If blocking layers and dielectric layers comprising zinc are used close to the silver layer, then scratch resistance is improved, but resistivity deteriorates due to species migration during heat treatment
Solution Approach 1:
A magnesium-based blocking layer is introduced as an intermediary between the zinc-containing dielectric layer and the silver layer. This intermediate layer acts as a diffusion barrier that prevents zinc species from migrating into the silver layer during heat treatment, thereby maintaining the electrical resistivity of the silver layer while still allowing the zinc dielectric layer to provide scratch resistance benefits
Solution Approach 2:
The blocking function is segmented into two distinct layers: a zinc-containing dielectric layer that provides scratch resistance and a magnesium-based blocking layer that prevents species migration. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between improving scratch resistance and maintaining resistivity
2Stability of the object's composition
If high-temperature heat treatment is applied to the stack, then optical and electrical properties are adjusted, but scratches become more visible and scratch resistance deteriorates
Solution Approach 1:
The magnesium-based blocking layer is deposited in advance during the stack fabrication process, before the high-temperature heat treatment is applied. This preliminary action ensures that the diffusion barrier is already in place to protect the silver layer from zinc species migration during the subsequent heat treatment, preventing deterioration of scratch resistance
Solution Approach 2:
The magnesium blocking layer serves as a protective cushion that absorbs and blocks the migratory zinc species during heat treatment. This beforehand cushioning prevents the harmful interaction between zinc and silver that would otherwise occur during high-temperature processing, thereby maintaining scratch resistance
3Manufacturing precision
If zinc-based dielectric layers are used to promote wetting and nucleation of the silver layer, then quality of the silver layer is improved, but species migration occurs during heat treatment affecting optical properties
Solution Approach 1:
The magnesium-based blocking layer is positioned between the zinc dielectric layer and the silver layer to serve as a selective barrier. It allows beneficial zinc species to remain in the dielectric layer for wetting and nucleation functions while blocking harmful zinc species migration into the silver layer during heat treatment, thereby preserving optical 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 zinc-based metallic layer improves scratch resistance and corrosion resistance while maintaining mechanical strength, reducing the visibility of scratches and preventing hot and cold corrosion, although it may slightly increase absorption and resistivity.
Implementation Method 1
control the diffusion of metallic zinc elements
Implementation Method 2
separated from this silver-based functional metallic layer by at least one intermediate oxide layer
Implementation Method 3
high-temperature heat treatments, such as an annealing, a bending and/or a tempering
Data Source
AI summary
A material including a transparent substrate coated with a stack of thin layers including at least one silver-based functional metallic layer and at least one zinc-based metallic layer. The zinc-based metallic layer is located above or below a silver-based functional metallic layer and separated from this silver-based functional metallic layer by at least one intermediate oxide layer based on one or more elements chosen from zinc, titanium, zirconium, tin, niobium, magnesium, hafnium and nickel.