Substoichiometric Zirconium Oxide Coating for Scratch Resistance and Low Haze
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Solution Overview
Problem
Existing window coatings face challenges with scratch resistance and 'blue haze' issues during high-temperature heat treatment, as materials like DLC oxidize and zirconium nitride transforms into zirconium oxide, causing micro-craze and increased haze values.
Innovation Solution
A substoichiometric zirconium oxide layer is sputter deposited on a glass substrate and heat treated in an oxygen atmosphere, transforming into a scratch-resistant stoichiometric zirconium oxide layer with reduced haze and improved durability, and optionally doped with tungsten for enhanced scratch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If DLC is used as a protective coating on glass substrate, then scratch resistance is improved, but the coating oxidizes and burns off during heat treatment at high temperatures
Solution Approach 1:
The patent changes the chemical composition parameters of the zirconium oxide layer by controlling oxygen partial pressure during deposition to create a substoichiometric composition (ZrO2-x) that transforms during heat treatment. This parameter change allows the coating to withstand heat treatment temperatures while maintaining scratch resistance through controlled oxidation to stoichiometric ZrO2.
Solution Approach 2:
The patent creates a composite structure where zirconium oxide layer combines the advantages of both DLC (scratch resistance) and heat treatment compatibility. The zirconium oxide acts as a base layer that can be heat treated, providing a stable platform that maintains protective properties throughout the heat treatment process.
2Strength
If zirconium nitride is converted into zirconium oxide during heat treatment, then scratch resistance is improved, but micro-craze and cracks develop causing blue haze
Solution Approach 1:
The patent performs preliminary action by depositing the zirconium oxide layer with controlled substoichiometric composition before heat treatment. This pre-configured composition is designed to transform controllably during heat treatment, preventing the formation of micro-craze and cracks that cause blue haze while still achieving the desired scratch resistance through oxidation to stoichiometric ZrO2.
Solution Approach 2:
The patent controls the oxygen partial pressure during deposition to create specific substoichiometric compositions (ZrO2-x where x is controlled). This parameter control allows the material to transform smoothly during heat treatment without developing the micro-craze and cracks that lead to blue haze, while still achieving high scratch resistance.
3Strength
If heat treatment is performed to transform coating materials, then scratch resistance is improved, but visible transmission decreases due to increased haze
Solution Approach 1:
The patent optimizes deposition parameters (oxygen partial pressure, power density, deposition rate) to create a substoichiometric zirconium oxide composition that transforms controllably during heat treatment. This parameter optimization ensures minimal haze formation while achieving the desired scratch resistance, thereby maintaining high visible transmission.
Solution Approach 2:
The patent creates local quality control by optimizing the composition and structure of the zirconium oxide layer at the molecular level through controlled oxygen incorporation during deposition. This local compositional control ensures uniform transformation during heat treatment, preventing localized defects that would scatter light and reduce visible transmission.
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 solution significantly reduces or eliminates 'blue haze' while maintaining or improving scratch resistance, increasing visible transmission, and providing a stronger crystalline structure with higher refractive index, making the coated articles more durable and easier to manufacture.
Implementation Method 1
heat treating the coated article causes the substoichiometric ZrOx layer to transform into a scratch resistant layer of or including stoichiometric or substantially stoichiometric zirconium oxide
Implementation Method 2
heat treated in an atmosphere including oxygen, which causes the substoichiometric ZrOx layer to transform into a scratch resistant layer of or including stoichiometric or substantially stoichiometric zirconium oxide
Implementation Method 3
a layer of or including substoichiometric zirconium oxide is sputter deposited, directly or indirectly, on a glass substrate via a substoichiometric zirconium oxide ceramic sputtering target
Data Source
AI summary
A layer of or including substoichiometric zirconium oxide is sputter deposited on a glass substrate via a substoichiometric zirconium oxide inclusive ceramic sputtering target of or including ZrOx. The coated article, with the substoichiometric ZrOx inclusive layer on the glass substrate, is then heat treated (e.g., thermally tempered) in an atmosphere including oxygen, which causes the substoichiometric ZrOx inclusive layer to transform into a scratch resistant layer of or including stoichiometric or substantially stoichiometric zirconium oxide (e.g., ZrO2), and causes the visible transmission of the coated article to significant increase.