Ceramic Coating with Embedded Spinel Nanoparticles for High-Temperature Color Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ceramic coatings with embedded particles, particularly color pigments, undergo chemical changes and color shifts during heat hardening and thermal stress, leading to unstable optical appearance in high-temperature applications like turbine blades.
Innovation Solution
Incorporating aluminum oxide nanoparticles with spinel-type colorant nanoparticles, ensuring the colorant nanoparticles remain stable at high temperatures and are exposed on the surface, either in a multilayer or gradient coating structure to maintain color integrity and indicate wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If color pigments are embedded in ceramic coating, then the coating has color and optical appearance, but the color changes during heat hardening and thermal stress
Solution Approach 1:
The patent changes the chemical composition parameters of the color pigment from conventional organic dyes to inorganic spinel-type compounds (e.g., FeCr2O4, CoAl2O4, MnAl2O4) that have stable crystal structures and color centers resistant to thermal decomposition and oxidation, thereby maintaining color stability at high temperatures up to 1000°C
Solution Approach 2:
The patent creates a composite coating system combining ceramic matrix (e.g., alumina, silica) with embedded spinel-type color pigment particles, where the ceramic provides structural stability and thermal resistance while the spinel particles provide color stability through their refractory nature and stable crystal field environment
2Ease of manufacture
If conventional particles are used in coating, then the coating can be produced, but stress fractures occur during rapid cooling
Solution Approach 1:
The patent employs a multi-layer coating structure with gradient composition where the color pigment concentration varies through the thickness, creating a progressive transition zone that gradually accommodates thermal stress and prevents sudden fracture during rapid cooling
Solution Approach 2:
The patent optimizes the particle size distribution and concentration gradient of spinel pigments through the coating thickness, with higher concentration at the surface and lower concentration deeper in the coating, creating a stress-distributing structure that prevents crack propagation during thermal cycling
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 maintains stable coloration under high temperatures (up to 1000°C) and prevents stress fractures, with the color intensity decreasing as the coating wears, providing a reliable wear indicator.
Implementation Method 1
the specified substances, which are already comparatively resistant to high temperatures per se, will be stabilized by an addition of aluminum oxide nanoparticles so that the colorant nanoparticles survive not only the heat treatment necessary for the creation of the coating without changing color but also survive thermal stresses arising over longer periods of operation
Implementation Method 2
the coating substance is applied to the substrate to be coated which is subsequently subjected to heat treatment, in order to achieve hardening of the coating. In this case a chemical conversion of the elements contained in the dispersion occurs simultaneously, which contributes to the formation of the ceramic framework of the coating
Implementation Method 3
the colorant nanoparticles must form a part of the surface so that their optical properties of absorption of specific light wavelengths are exploited
Implementation Method 4
the resistance to changes in temperature of the coatings is also improved. This means that the formation of stress fractures even when the layers cool down rapidly is avoided
Data Source
AI summary
The subject matter of the invention is a component which is provided with a ceramic coating forming the surface. Inventively there is provision at least in a cover layer of the coating for nanoparticles made from a colorant (CrCoAl or a spinel-type oxide) and aluminum oxide nanoparticles. This combination of nanoparticles in the coating advantageously results in a resistance to high temperatures of the coloring of the surface of up to 1000° C. not previously known. This allows even components under great stress, such as for example compressor or turbine blades of a gas turbine, to be provided with temperature-resistant coloring. This can then be used for an optical inspection for example. Protection is also claimed for a method for creating the inventive coating.