Reversible Thermochromic Ceramic Coating for High-Temperature Durability
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Solution Overview
Problem
Existing thermochromic coatings lack heat resistance and durability for high-temperature applications, and pigments containing heavy metals pose toxicity concerns, limiting their use in cooking and heating products.
Innovation Solution
A reversible thermochromic ceramic coating composition is developed by grinding silica sol with Fe2O3 and additional compounds using a ball mill, combined with metal powders like Ag, Cu, and Al, which provides heat resistance up to 400°C and durable color changes between 100°C and 150°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If microcapsule-based thermochromic pigments are used for color change at 50-70°C, then reversible low-temperature thermochromism is achieved, but the capsule is destroyed and gas is generated when heated to 300°C or higher
Solution Approach 1:
The patent uses a composite structure consisting of thermochromic microcapsules embedded in a ceramic coating matrix. The ceramic material (containing Fe2O3, SiO2, Al2O3, etc.) provides high-temperature stability and protects the microcapsules from destruction at 300°C+, while the microcapsules maintain thermochromic functionality at lower temperatures (50-70°C). This composite approach allows the system to exhibit both low-temperature color change and high-temperature durability.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the coating system by incorporating ceramic particles with specific size ranges (0.1-10 μm) and compositional ratios. The ceramic matrix changes the thermal environment experienced by the microcapsules, raising their effective heat resistance threshold while preserving their thermochromic transition temperature through controlled parameter optimization.
2Illumination intensity
If cadmium-based pigments (red, yellow, orange) are used for coloration, then vibrant colors are achieved, but toxic properties of heavy metals limit use in cooking container interiors
Solution Approach 1:
The patent extracts and removes the toxic cadmium component from the pigment system while retaining the desired coloration function. Instead of using cadmium-based pigments, the invention employs iron oxide (Fe2O3) as the primary coloring agent, which provides red, yellow, and orange hues without the heavy metal toxicity. This extraction of the harmful substance while preserving the functional property (coloration) resolves the contradiction between color vibrancy and safety.
Solution Approach 2:
The patent replaces expensive and toxic cadmium pigments with cheaper, non-toxic iron oxide pigments. While cadmium pigments may offer slightly superior color intensity, iron oxide provides sufficient coloration for practical applications and eliminates toxicity concerns, making it suitable for cooking container interiors where safety is paramount.
3Adaptability or versatility
If existing thermochromic coatings are used for high-temperature applications, then color change function is achieved, but durability and heat resistance are insufficient
Solution Approach 1:
The patent creates a durable thermochromic coating by combining thermochromic microcapsules with a ceramic matrix containing Fe2O3, SiO2, Al2O3, and other oxides. The ceramic component provides exceptional heat resistance (stable up to 400°C) and mechanical durability, while the embedded microcapsules maintain thermochromic functionality. This composite structure allows the coating to withstand repeated heating cycles, abrasion, and chemical exposure in cooking applications.
Solution Approach 2:
The patent applies preliminary protective action by embedding the thermochromic microcapsules within the robust ceramic matrix before the coating is applied to the substrate. This pre-encapsulation and matrix integration provide inherent protection against mechanical damage, thermal shock, and chemical degradation, ensuring long-term durability while preserving the thermochromic effect.
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 coating composition exhibits stable heat resistance and durability, allowing for reversible color changes at low temperatures and maintaining performance up to 400°C, with enhanced wear, chemical, and mechanical properties, suitable for kitchen and heating applications.
Implementation Method 1
a reversible thermochromic ceramic coating agent in which colors change depending on temperatures by absorbing (absorption and radiation are equivalent) all the light from a near infrared region
Implementation Method 2
colors change depending on temperatures by absorbing (absorption and radiation are equivalent) all the light from a near infrared region
Implementation Method 3
grinding a silica sol, Fe 2 O 3 or additional compounds as a pigment and filler using a ball mill
Data Source
Figure 1
AI summary
The present invention relates to a reversible color changeable coating composition and a preparation method thereof. The plate of the present invention has heat resistance of 400℃ or higher thereby can be used for heating products very stably, and the durability of the plate increases since it has excellent wear resistance, chemical resistance and mechanical properties. In addition, beautiful colors can be obtained by mixing colors in various ways, and being heated can be identified with the naked eye since the color changes when heated.