Several TA methods (including dynamic TA, Q-TA, emanation and special conductometric TA) were used in investigations of condensed
phosphate synthesis, and in the evaluation and control of the reactivity of the raw materials, when high-temperature stable
pigments are developed. Conductometric TA occupies a special position because of its high sensitivity to most changes in crystal
structure at the beginning of reactions.
Authors:C. Xavier, C. Costa, S. Crispim, M. Bernardi, M. Maurera, M. Conceiçăo, E. Longo and A. Souza
The pigments used in ceramic applications are of nature predominantly inorganic and they should be thermally stable, insoluble
in glazing, resistant to the chemical and physical agents' attacks. This work aimed at the synthesis by the polymeric precursor
method of ZrO2-based inorganic pigments, doped with Fe, Ni, Co, Cr and Cu cations. The fired pigments were characterized by thermogravimetry
(TG), differential thermal analysis (DTA) and X-ray diffraction (XRD). Among the metals used to zirconium-doping, the best
result was achieved with the cations Cu, which presented the monophase pigment, even as 20 mol% of dopant. Up to the temperature
of 1000C the pigments presented a good thermal stability.
Authors:M. Bernardi, E. Leite, E. Longo, M. Conceiçăo and A. Souza
The color efficiency of ceramic glaze blue pigments obtained by the Pechini method was presented in this work. The fired pigments
and enameled samples were characterized by thermogravimetry (TG) and differential thermal analysis (DTA), XRD, UV-VIS-NIR
spectroscopy and CIE-L*a*b* color-measurements. The pigments obtained by the Pechini method present a better solubility in
the molten glazes than the pigments obtained by the mechanical mixture of the precursor oxides.
Authors:R. Prasanna, A. Sood, A. Suresh, S. Nayak and B. Kaushik
A wide variety of pigments, like chlorophyll, carotenoids and phycobiliproteins, which exhibit colours ranging from green, yellow, brown to red are present in algae. Increasing awareness of harmful effects of synthetic dyes and inclination of society towards the usage of natural products, such as plant / microbial based colours in food and cosmetics, has led to the exploitation of microalgae as a source of natural colours. Algal pigments have great commercial value as natural colorants in nutraceutical, cosmetics and pharmaceutical industry, besides their health benefits.
capsules are now commonly prescribed health foods for improving vitality and longevity of human beings. This review describes the distribution, structure of these pigments in algae, with emphasis on specific techniques for extraction and purification, along with different methods of biomass production and commercially feasible techniques documented in literature. An overview of the industrial applications of these natural colouring agents in diagnostics, food and cosmetics industry is also provided.
An intense blue organo-clay color pigment was obtained by adding naphthyl-1-ammonium chloride to a Na-montmorillonite aqueous
suspension followed by treatment with sodium nitrite. This treatment resulted in the synthesis of the azo dye 4-(1-naphthylazo)-1-naphthylamine
adsorbed onto the clay. The pigment was subjected to thermo-XRD-analysis and the diffractograms were curve-fitted. Heating
naphthylammonium-montmorillonite at 360°C resulted in the evolution of the amine at temperatures lower than those required
for the formation of charcoal and consequently the clay collapsed. On the other hand, heating the pigment at 360°C resulted
in the conversion of the adsorbed azo dye into charcoal. The clay did not collapse, thus proving that the azo dye was located
inside the interlayer space. Before the thermal treatment a short basal spacing in the pigment compared with that in the ammonium
clay (1.28 and 1.35 nm, respectively) indicated stronger surface π interactions between the clayey O-plane and the azo dye
than between this plane and naphthylammonium cation. The amount of dye after one aging-day of the synthesis-suspension increased
with [NaNO2]/[C10H7NH3] ratio but did not increase with naphthylammonium when the [NaNO2]/[C10H7NH3] ratio remained 1. After 7 and 56 aging days it decreased, indicating that some of the dye decomposed during aging.
Authors:Petra Šulcová, Lucie Vitásková and Miroslav Trojan
The research activities in the field of ceramic pigments are focused on investigation of pigments with thermal stability, ecological purity and interesting colour hues. The most requisite hues are yellow, pink