Nanolaminate Coating for Scratch Resistance
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Solution Overview
Problem
Nanolaminate coatings with alternating inorganic silica and silicon-based organic-inorganic layers exhibit unsatisfactory mechanical properties, specifically low Young's modulus and indentation hardness, leading to a low H/E ratio, which is inadequate for applications requiring both optical transparency and mechanical durability.
Innovation Solution
A nanolaminate coating with a thickness ranging from 20 to 500 nm, comprising alternating layers of inorganic silica and silicon-based organic-inorganic layers, where the first layer is obtained by evaporation of silicon oxide and the second layer by deposition of organosilicon compounds under ionic or plasma assistance, achieving a refractive index lower than 1.58 and improved mechanical properties with a higher H/E ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SiOCH organic-inorganic layers are used to replace brittle SiO2, then flexibility is improved, but mechanical properties (Young's modulus and indentation hardness) deteriorate
Solution Approach 1:
The patent applies composite materials by creating a nanolaminate structure that alternates between SiO2 mineral layers and SiOCH organic-inorganic layers. This composite approach allows the coating to simultaneously achieve the flexibility needed for plastic substrates and the mechanical strength required for durability, as the inorganic SiO2 layers provide structural rigidity while the organic-inorganic SiOCH layers provide flexibility and adhesion.
Solution Approach 2:
The patent segments the coating into multiple thin nanolayers alternating between two different materials (SiO2 and SiOCH). This segmentation into alternating layers allows each material to contribute its specific properties - the inorganic layers provide hardness and the organic-inorganic layers provide flexibility - resulting in a coating that exhibits both properties simultaneously, resolving the contradiction between flexibility and mechanical strength.
2Illumination intensity
If nanolaminate coatings are formed with alternating SiO2 and SiOCH layers, then optical transparency is maintained, but scratch and wear resistance deteriorates due to low H/E ratio
Solution Approach 1:
The nanolaminate coating uses a composite structure alternating between SiO2 and SiOCH layers, where the inorganic SiO2 layers contribute to scratch and wear resistance while maintaining optical transparency, and the organic-inorganic SiOCH layers provide flexibility. The alternating structure ensures that the hard inorganic layers are distributed throughout the coating, providing multiple barriers against scratching while the overall coating remains transparent.
Solution Approach 2:
The patent applies local quality by having different layers perform different functions within the same coating system. The SiO2 layers are positioned to provide local regions of high hardness and wear resistance, while the SiOCH layers provide local regions of flexibility and adhesion. This spatial differentiation of properties within the nanolaminate structure allows the coating to simultaneously achieve scratch resistance and optical transparency.
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 nanolaminate coating demonstrates enhanced mechanical properties, including a higher Young's modulus and indentation hardness, resulting in improved scratch resistance and tribological performance, suitable for applications such as ophthalmic lenses and optoelectronic devices.
Implementation Method 1
the first layer being an inorganic silica layer obtained by evaporation of silicon oxide, especially evaporation of SiO 2
Implementation Method 2
the second layer being a silicon-based organic-inorganic layer obtained by deposition of an organosilicon compound or a mixture of organosilicon compounds under ionic or plasma assistance
Data Source
Figure 1~3
Figure 2
AI summary
The invention concerns an article comprising a nanolaminate coating, wherein the nanolaminate coating has a total thickness ranging from 20 to 500 nm and comprises at least one pair of layers constituted of adjacent first and second layers and a minimum of three layers, said first layer being an inorganic silica layer obtained by evaporation of silicon oxide, especially evaporation of SiO2, and the second layer being a silicon-based organic-inorganic layer obtained by deposition of an organosilicon compound or a mixture of organosilicon compounds under plasma or ionic assistance, and wherein the refractive index of the nanolaminate coating as a whole is lower than 1.58 at 550 nm.