Sol-Gel/PEEK Composite Coating for Scratch-Resistant Cookware
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Solution Overview
Problem
Existing sol-gel ceramic coatings for cooking surfaces have limited mechanical resistance due to their brittle nature, leading to scratching and chipping when subjected to culinary use stresses.
Innovation Solution
A composite coating is developed by applying a macroporous sublayer made from a mixture of thermoplastic and/or thermostable polymers, such as PEEK, directly onto a metal substrate without pre-heating, followed by the application of sol-gel ceramic layers, which significantly improves the mechanical properties and adhesion of the coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sol-gel ceramic coating is applied directly to metal substrate, then coating adhesion is improved, but mechanical resistance to scratching and chipping deteriorates due to brittle nature
Solution Approach 1:
The patent applies a composite coating structure consisting of two distinct layers: a polymeric sublayer (PEEK or PAEK) applied first to the metal substrate, followed by a sol-gel ceramic coating layer. This composite structure combines the toughness and flexibility of the polymer sublayer with the hardness and chemical resistance of the sol-gel ceramic layer, thereby improving both adhesion and mechanical resistance to scratching and chipping.
2Reliability
If pre-heating above 200°C is applied to substrate before coating, then hard base adhesion is improved, but energy consumption and process complexity increase
Solution Approach 1:
The patent changes the temperature parameter from high-temperature pre-heating (>200°C) to low-temperature or room temperature application. The polymeric sublayer is applied without pre-heating the metal substrate above 200°C, and the sol-gel coating is applied at temperatures below the melting point of the polymer, eliminating the need for expensive pre-heating equipment and reducing energy consumption.
3Strength
If double firing at temperature above 500°C is applied, then enamel hard base properties are improved, but manufacturing cost and process time increase
Solution Approach 1:
The patent dramatically reduces the firing temperature from above 500°C to below the melting point of the polymeric sublayer (typically 300-400°C for PEEK/PAEK). This single low-temperature firing step cures the sol-gel coating while preserving the polymeric sublayer, eliminating the need for double firing and significantly reducing both manufacturing cost and process time.
4Strength
If discontinuous hard base is applied by flame or arc spray, then impact resistance is improved, but scratch resistance remains limited and installation cost increases
Solution Approach 1:
The patent uses a composite approach where a polymeric sublayer (applied by conventional coating methods) provides the base layer, followed by a sol-gel ceramic coating that enhances scratch resistance. This combination achieves both improved impact resistance from the polymeric sublayer and enhanced scratch resistance from the sol-gel ceramic layer, while avoiding the need for expensive flame or arc spray equipment.
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 composite coating achieves excellent scratch resistance and mechanical impact resistance, allowing for the use of metal utensils without causing major damage, while also maintaining non-stick properties and aesthetic appeal.
Implementation Method 1
combining silica-based metal alkoxides (silanes) or alumina-based metal alkoxides (aluminates)... coatings made from fluorinated resin of the PTFE type... sol-gel chemistry
Implementation Method 2
combining silica-based metal alkoxides (silanes) or alumina-based metal alkoxides (aluminates)... sol-gel chemistry
Implementation Method 3
applying a macroporous sublayer made from a mixture of thermoplastic and/or thermostable polymers, such as PEEK, directly onto a metal substrate
Data Source
AI summary
A culinary item includes a hollow metal cup having a bottom and a sidewall extending up from the bottom, said cup having a concave interior face designed to accept food products and a convex exterior face, said interior face or said bottom being coated with a coating which consists successively, starting from the cup, in a hard sub layer and a sol-gel coating, wherein the hard sub layer takes the form of a discontinuous layer, in that the hard sublayer is porous and in that the hard sublayer is made up of one or more non-fluorinated polymer materials selected from polyetherary I ketones (PEAK) and mixtures thereof, possibly containing hard inorganic fillers, possibly conductive fillers and possibly less than 3 wt % of additives with respect to the weight of the hard sublayer.