Colour analysis of some cobalt-based blue pigments

Llusar, M.; Forés, A.; Badenes, J.A.; Calbo, J.; Tena, M. A.; Monrós, G.

doi:10.1016/s0955-2219(00)00295-8

Cited by 229 publications

(150 citation statements)

References 3 publications

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“…Experimental results reported on this topic show that the traditional methodology for preparation of spinels via ceramic method involves annealing at temperatures up to 1400ºC and long soaking times [2]. During this thermal treatment, solid state reactions take place and the chromophore cations are incorporated into the newly generated host lattice.…”

Section: Introductionmentioning

confidence: 99%

Characteristics reproducibility of (Fe, Co)(Cr, Al) 2 O 4 pigments obtained by solution combustion synthesis

Gilabert

Palacios

Sanz

et al. 2016

Ceramics International

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Synthesis reproducibility of mixed spinels Fe 1-Ψ Co Ψ Cr 2-2Ψ Al 2Ψ O 4 (0≤Ψ≤1), obtained by Solution Combustion Synthesis using urea as fuel, has been studied. Pigments with spinel structure Fd-3m have been obtained for all the compositional range analyzed. Characteristics such as crystallinity, cell parameter, crystal size and specific surface area show a noticeable dependence with Ψ, but some of them present a low reproducibility, indicating a pronounced dependency with process conditions in each batch.Colouring power of synthesized pigments is highly significant, so they can be directly integrated in ceramic glasses without introducing a second thermal treatment. However, the generated colour also suffers from a limited reproducibility. IntroductionSolution combustion synthesis (SCS) is an innovative method to synthesize ceramic pigments, which allows obtaining materials in a direct pathway, with a low particle size, using short reaction times and moderate temperatures [1].Experimental results reported on this topic show that the traditional methodology for preparation of spinels via ceramic method involves annealing at temperatures up to 1400ºC and long soaking times [2]. During this thermal treatment, solid state reactions take place and the chromophore cations are incorporated into the newly generated host lattice. However, due to the elevated temperature reached during the process, the resulting pigment presents low specific surface area and high particle size, which is reflected in a low colouring power. For this reason, in the industrial practice a milling operation of the pigment is mandatory in order to obtain a marketable product. In addition, the ink-jet technology applied to ceramic decoration requires pigments with a particle size around 500 nm, which supposes an increase in the cost of the milling stage and a change in the milling technology. As a consequence, there is a growing demand for alternative routes for synthesizing pigments that give directly particle sizes near to the interval recommended for ink-jet machines. SCS is a method suitable to overcome some important disadvantages of ceramic pigment traditional processing because it could generate pigments as low cohesive masses formed of nanograins, easier to mill up to the submicrometer interval.3 SCS method begins with a concentrated aqueous solution of precursors of the desired product (being the nitrates the most frequently used), and a suitable fuel (glycine, urea, hexamethylentetraamine, hydrazine and their derivates, etc.). The solution is heated at high rate in order to evaporate all water and, afterwards, to ignite the fuel present in the solid residue, which supplies enough energy to carry out the synthesis reaction. The reaction product is frequently obtained as a spongy mass.SCS has been used to synthesize large number of inorganic materials, either simple Most of the spinel-type ceramic industrial pigments include more than three metals in their composition to adjust the final colour. As a consequence, it was investi...

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Section: Introductionmentioning

confidence: 99%

Characteristics reproducibility of (Fe, Co)(Cr, Al) 2 O 4 pigments obtained by solution combustion synthesis

Gilabert

Palacios

Sanz

et al. 2016

Ceramics International

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“…The application of different calcination temperatures lead to shift in color parameters with an enhancement of blue color [2,3,16]. The pigments CoT, as-prepared CoAl 2 O 4 0 and Co1200 were tested using transparent glazes and ceramic bodies.…”

Section: Resultsmentioning

confidence: 99%

CoAl2O4 blue nanopigments prepared by liquid-feed flame spray pyrolysis method

Granados

Laine

et al. 2015

Matéria (Rio J.)

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CoAl 2 O 4 pigments were synthesized through Liquid-Feed Flame Spray Pyrolysis (LF-FSP) method using metallorganic precursors of cobalt propionate and alumatrane. The precursors were dissolved in ethanol and aerosolized into a methane/oxygen flame where it was combusted to result in nanopowders at a single step. The resulting nanopowders were collected in electrostatic precipitators and analyzed by x-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), colorimetry, Field Emission Scanning Electron Microscopy (FE-SEM) and BET (Brunauer-Emmett-Teller) nitrogen adsorption. Results show formation of single phase blue nanopigments, suggesting that LF-FSP is an excellent method to produce nanoparticles with high quality in a continuous process for new industrial applications. The nanoparticles presented spherical morphology with specific surface area of 50 m 2 /g, corresponding to average particle size of 27 nm. The pigments were calcined at 500, 600, 800, 1000, 1200 and 1300 °C, aiming to find the color stability whereby the colors were measured using the color space CIE L*a*b* under standardized D65 light. The brightest and bluest was obtained at calcination temperature of 1200°C and its application into a glaze was carried out at 1200 °C to evaluate the color performance and stability after a decoration process. Finally, LF-FSP produced pigments were compared with those produced by solid state reaction. Differences in the color due to the average particle size and process conditions were observed. It is possible to obtain new hues for ceramic applications by LF-FSP method.

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“…When x > 4, Co 2+ ions occupy tetrahedral sites, as well. As CoO 4 has a blue reflectance [3], the resulting pigment displays a green color. This result is in agreement with Poleti et al and Hie et al [5,7], who observed a tendency of a higher amount of Co 2+ ions in octahedral sites, when x < 4.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, the coloring performance of cobalt pigments depends very much on the coordination of Co 2+ ions (tetrahedral coordination is preferred to octahedral) [2,3]. The difference in the color of a chromophore at different coordinations is explained using the ligand field theory.…”

Section: Introductionmentioning

confidence: 99%

Color and structural analysis of CoxZn7−xSb2O12 pigments

Gouveia

Soledade

Paskocimas

et al. 2006

Materials Research Bulletin

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The polymeric precursor method was successfully used to synthesize Co x Zn 7Àx Sb 2 O 12 (x = 0-7) powders. Pigments were evaluated using colorimetry, X-ray diffraction, UV-vis and infrared spectroscopy. The optical band gap values vary with the Co 2+ substitution. These results suggest that the concomitant presence of Co and Zn in the spinel lattice leads to the rupture of the Végard law, as well as other properties of the studied system, such as unit cell volume. The Co-richer samples display a higher absorbance than the Co-lean samples. The high absorption of the Co 7 Sb 2 O 12 sample at most of the visible region makes this compound a candidate for a black pigment. It was shown that color depends on the site where the chromophore ion is located, in agreement with the ligand field theory. #

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Colour analysis of some cobalt-based blue pigments

Cited by 229 publications

References 3 publications

Characteristics reproducibility of (Fe, Co)(Cr, Al) 2 O 4 pigments obtained by solution combustion synthesis

Characteristics reproducibility of (Fe, Co)(Cr, Al) 2 O 4 pigments obtained by solution combustion synthesis

CoAl2O4 blue nanopigments prepared by liquid-feed flame spray pyrolysis method

Color and structural analysis of CoxZn7−xSb2O12 pigments

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