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Updated: Dec 31, 2025
12:04
Exfoliation of Egyptian Blue and Han Blue, Two Alkali Earth Copper Silicate-based Pigments
Published on: April 24, 2014
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Hibonite Blue: A New Class of Intense Inorganic Blue Colorants
Brett A Duell1, Jun Li1, M A Subramanian1
1Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States.
ACS Omega
|January 1, 2020
Summary
New hibonite blue pigments offer a safer, more vibrant alternative to hazardous cobalt blue. These pigments significantly reduce carcinogenic cobalt content while enhancing color properties and lowering costs.
Area of Science:
- Materials Science
- Inorganic Chemistry
- Color Science
Background:
- Commercial cobalt blue (CoAl2O4) contains carcinogenic Co2+, posing environmental and health risks.
- Development of safer, high-performance blue pigments is crucial for sustainable applications.
Purpose of the Study:
- To synthesize and characterize a new class of blue pigments based on the hibonite structure.
- To investigate the color properties and cobalt content of these novel pigments as alternatives to cobalt blue.
Main Methods:
- Solid-state synthesis of CaAl12-2xCoxTixO19 (0 < x ≤ 1) solid solution series.
- Crystallographic analysis to confirm the hibonite structure.
- Spectroscopic analysis to determine the origin of the blue color and cobalt concentration.
Main Results:
- The synthesized CaAl12-2xCoxTixO19 pigments crystallize in the hexagonal hibonite structure.
- The intense blue color arises from Co2+ in tetrahedral and trigonal bipyramidal sites, exhibiting tunable hues.
- Cobalt content was reduced from 33% to as low as 4% by mass compared to commercial cobalt blue, with enhanced color properties.
Conclusions:
- The novel hibonite blues offer a promising, environmentally benign alternative to cobalt blue.
- These pigments provide tunable, intense blue colors with significantly reduced carcinogenic cobalt content.
- The reduced cobalt concentration and enhanced color properties present a cost-effective and safer option for blue pigment applications.
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