Coated Substrate with Sol-Gel Protection for Heat Treatment
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Solution Overview
Problem
Soft coatings used in solar control or insulating low-E applications have limited mechanical, chemical, and corrosion resistance, which restricts their use in glazing due to susceptibility to damage from environmental exposure and handling, and they are not heat-treatable without compromising their integrity.
Innovation Solution
A coated substrate is developed with a soft coating layer deposited by physical vapor deposition, topped with a sol-gel coating containing silicon oxide, titanium oxide, or zirconium oxide, and cerium oxide, and a protective organic polymer layer, which enhances mechanical, chemical, and corrosion resistance both before and after heat treatment, allowing for environmental exposure without compromising emissivity or aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft coating is applied to provide solar control or insulating low-E properties, then the emissivity and energy control are improved, but the mechanical, chemical, and corrosion resistance deteriorate
Solution Approach 1:
The coating system is segmented into multiple functional layers: a soft coating layer (PVD-deposited metal oxide) providing solar control and insulating properties, and a separate protective coating layer (sol-gel derived) providing mechanical, chemical, and corrosion resistance. This segmentation allows each layer to specialize in its function without compromising the other.
Solution Approach 2:
The invention creates a composite coating structure combining the soft coating material (e.g., silver, aluminum oxide) with a sol-gel protective coating (silica-based with cerium oxide). The composite structure integrates the optical properties of the soft coating with the protective properties of the sol-gel layer, achieving both low emissivity and high durability.
2Reliability
If a soft coating is used for solar control applications, then the IR blocking ability is improved, but the durability against environmental exposure deteriorates
Solution Approach 1:
The sol-gel protective coating acts as an intermediary layer between the soft coating and the external environment. It shields the soft coating from direct exposure to UV radiation, humidity, and chemical contaminants while allowing the soft coating to maintain its IR blocking function. The cerium oxide in the sol-gel layer specifically addresses UV protection.
Solution Approach 2:
The sol-gel coating undergoes parameter changes through controlled hydrolysis and condensation reactions, transforming from a liquid precursor solution to a dense, cross-linked gel structure. This parameter change (from liquid to solid gel) creates a durable protective barrier that enhances long-term environmental resistance.
3Reliability
If a soft coating is deposited by physical vapor deposition, then the opto-energetic properties are improved, but the susceptibility to mechanical damage during handling increases
Solution Approach 1:
The sol-gel protective coating is applied beforehand to cushion and protect the fragile soft coating from mechanical damage during subsequent handling, shipping, and installation. This prior protective layer prevents scratches, chips, and other mechanical injuries that would otherwise compromise the opto-energetic properties of the soft coating.
4Strength
If a protective layer is added to a soft coating, then the mechanical resistance is improved, but the complexity of the coating structure increases
Solution Approach 1:
The sol-gel protective coating is designed to perform multiple functions simultaneously: providing mechanical strength, chemical resistance, corrosion protection, and UV blocking (through cerium oxide). This multi-functionality reduces the need for additional separate protective layers, thereby limiting the increase in overall structure complexity while maximizing protective capabilities.
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 coated substrate achieves improved durability and resistance to mechanical, chemical, and corrosion attacks, enabling its use on exterior glazing surfaces and withstanding heat treatment, thus expanding its application in energy-saving applications like buildings and transportation.
Implementation Method 1
The sol-gel coating aims at efficiently blocking ultraviolet (UV) radiations and comprises very high amounts of cerium oxide as UV blocker
Implementation Method 2
a soft coating comprising one or more layers deposited by physical vapor deposition provided on at least a part of at least one face of the substrate
Data Source
AI summary
The present invention relates to a coated substrate comprising: -a substrate, -a soft coating, -a sol-gel coating comprising: - silicon oxide, - at least one of titanium oxide or zirconium oxide, - cerium oxide in a theoretical weight ratio of cerium oxide/silicon oxide ranging from 0 to 0.03, -a protective coating comprising at least one organic polymer, to a process for making a coated substrate, to a densified coated substrate and to glazing units comprising such densified coated substrate.