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Inorganic yellow-red pigments without toxic metals
1Max-Planck-Institut fur Festkorperforschung, Stuttgart, Germany. martin@jansen.mpi-stuttgart.mpg.de
Nature
|May 9, 2000
Summary
New perovskite pigments offer a safer, high-performance alternative to traditional cadmium-based colorants. These cadmium-free inorganic pigments provide excellent stability and tunable colors for high-temperature applications.
Area of Science:
- Materials Science
- Inorganic Chemistry
- Pigment Technology
Background:
- Inorganic pigments are crucial for coloring materials processed at high temperatures, especially in glasses, glazes, and ceramics.
- Many current inorganic pigments contain heavy or transition metals, posing environmental and health risks, with cadmium-based pigments being a particular concern due to cadmium's toxicity.
- Regulations increasingly restrict cadmium pigment use, driving demand for safer, high-performance alternatives.
Purpose of the Study:
- To identify and evaluate novel, non-toxic inorganic pigment candidates as substitutes for cadmium-based pigments.
- To assess the performance characteristics of these new pigments, including color, stability, and applicability in high-temperature environments.
- To demonstrate a viable pathway for reducing cadmium emissions from pigment usage.
Main Methods:
- Synthesis and characterization of solid solutions based on perovskites CaTaO2N and LaTaON2.
- Tuning pigment color by adjusting the composition of the perovskite solid solutions.
- Evaluation of key pigment properties: brilliance, tinting strength, opacity, dispersability, light-fastness, and heat stability.
Main Results:
- Solid solutions of CaTaO2N and LaTaON2 demonstrate performance comparable to cadmium pigments in terms of brilliance, tinting strength, opacity, dispersability, light-fastness, and heat stability.
- The color of these perovskite pigments can be effectively tuned across the yellow, orange, and red spectrum through simple compositional modifications.
- All constituent elements in the developed perovskite system are identified as harmless.
Conclusions:
- Perovskite-based inorganic pigments, specifically solid solutions of CaTaO2N and LaTaON2, present a promising, inherently safer alternative to cadmium-based pigments.
- This new pigment system offers comparable performance and tunable colors, addressing the need for cadmium-free solutions in high-temperature applications.
- The development contributes to reducing environmental cadmium emissions and mitigating concerns regarding pigment safety.
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