Colour performance of ceramic nano-pigments (original) (raw)
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Ceramic pigments for digital decoration inks: an overview
The field of ceramic colorants is one of the most conservative in tile making. Reduction of cost and impact on health and the environment have been the driving force for innovation in pigment manufacturing, where the main technological goals were fast synthesis routes and minimizing hazardous components and additives. The advent of digital decoration is overviewed with its paradigm shift from colorant to ink. The requirements for ink-jet printing are reviewed: rheological properties, surface tension, zeta potential, sedimentation, drop size and shape, kinetics of penetration, particle size, control of electrical and magnetic properties, stability in organic media, improved colorant strength. As conventional pigments and dyes proved to be unsuitable for digital decoration, colorant manufacturers were forced to upgrade processing (micronizing step for pigments) and to become involved in ink design (improving colorant strength for dyes). By this way, different classes of colorants for digital ink have been developed: organo-metallic complexes, micronized pigments, colloidal metals, nanopigments and reactive sol precursors for in-situ synthesis. The main challenges for ink manufacturers are still the stability over time (sometimes limited to a few weeks) and the gamut (much narrower than that of conventional ceramic colorants). As a matter of fact, typical quadrichromy or hexachromy is still a hard task to be achieved with ceramic colorants and tile makers are often choosing unconventional colour sets based on brown shades. This circumstance is revitalizing the industrial interest towards alternative routes for pigment synthesis (chimie douce or bottom-up approach) and technological solutions to improve the colour performance (pigment coating, core-shell structures, use of primers and buffers). Physico-chemical properties of inks, which affect the stability over time, are turning critical with increasing diffusion of digital decoration. From this standpoint, technologies able to control colloidal suspensions and to design hybrid organic-inorganic composites are rapidly gaining interest and application potential.
Journal of the European Ceramic Society, 2014
Different types of nano-CoAl 2 O 4 pigments were prepared by controlling concentration of cetyltrimethylammonium bromide (CTAB) and polyvinyl pyrrolidone (PVP) as double capping agents in a co-precipitation process. The prepared nano-CoAl 2 O 4 pigments were characterized by TGA, UV spectroscopy, and XRD. The optimum synthesized nano pigment was well dispersed into de-ionized water to form the ink. Rheology, surface tension and DLS of the prepared ink were examined. The prepared ink was printed onto a ceramic substrate. The printing process was repeated 1, 3 and 5 times in order to evaluate variations in the optical properties by changing thicknesses of the printed film. Appearance of the printed image and morphology of the prepared nano-pigments were observed by SEM. Moreover, shape and size of the nano-particles in the prepared ink were investigated by TEM. The obtained results revealed that the ink-jet printing method can be used to produce a nano-film of pigments on the ceramic.
Obtaining and Characterization of New Ceramic Pigments for Polychrome Artistic Elements
The paper presents the thermal characterisation of 18 photostable pigments obtained by co-precipitation in aqueous systems, based on precursors with chromophore structures of zinc phosphate and chromate, chemically doped with Mn(II), Fe(II), Fe(III), Co(II), Ni(II) and Bi(III) cations. The thermal analysis of the precursors highlighted the thermal stability of the pigments and the mass losses, as well as the phase changes that occurred within the 25 -900°C temperature range. Based on the acquired data the 18 pigments were grouped, according to their thermal stability, into possible domains of application: obtaining glazed polychrome elements and water and oil based paints. Even if they were obtained from the same precursors, namely zinc phosphate and chromate, as basic materials for synthesizing ceramic pigments by doping with chromophore cations, after co-precipitation in aqueous systems the obtained pigments had different thermal behaviour. Thus, the first group contains pigments with high chemical and thermal stability, namely P. 1, P.2, P.3, P.4, P.7, P.9, P.17 and P.18, that are suitable in fritted applications for polychrome tiles for mosaics and stained glasses. The second group, that of the less stable pigments, can be used for oil or water based painting, includes: P.5, P. 6, P.8, P.10, P.11, P.12, P.13, P.14, P.15 and P.16.
Synthesis and characterization of new nano-particles as blue ceramic pigment
The synthesis of a new nano-blue ceramic pigment Co x Mg 1−x Al 2 O 4 (0 ≤ x ≤ 0.1) using the combination between co-precipitation and combustion synthesis (CS) method. The structure of pigments is assigned based on thermogravimetric and differential thermogravimetric analysis (TG-DTGA), X-ray diffractions (XRD), and UV-vis spectroscopy. Also, diffuse reflectance spectroscopy (DRS) using CIE L*a*b* parameter measurement method, infrared spectroscopy (IR) and transmission electron microscopy (TEM) is used. The result revealed that the nano-size particle pigment was obtained in range 24-35 nm by using 3-methyl-pyrozole-5-one (3MP5O) as a fuel at 400 • C in open furnace. Also, results show the varying colors and particles' size as a result of different calcination temperatures from 500 to 1200 • C for 2 h.
The paper presents the thermal characterisation of 18 photostable pigments obtained by co-precipitation in aqueous systems, based on precursors with chromophore structures of zinc phosphate and chromate, chemically doped with Mn(II), Fe(II), Fe(III), Co(II), Ni(II) and Bi(III) cations. The thermal analysis of the precursors highlighted the thermal stability of the pigments and the mass losses, as well as the phase changes that occurred within the 25 -900°C temperature range. Based on the acquired data the 18 pigments were grouped, according to their thermal stability, into possible domains of application: obtaining glazed polychrome elements and water and oil based paints. Even if they were obtained from the same precursors, namely zinc phosphate and chromate, as basic materials for synthesizing ceramic pigments by doping with chromophore cations, after co-precipitation in aqueous systems the obtained pigments had different thermal behaviour. Thus, the first group contains pigments with high chemical and thermal stability, namely P. 1, P.2, P.3, P.4, P.7, P.9, P.17 and P.18, that are suitable in fritted applications for polychrome tiles for mosaics and stained glasses. The second group, that of the less stable pigments, can be used for oil or water based painting, includes: P.5, P. 6, P.8, P.10, P.11, P.12, P.13, P.14, P.15 and P.16.
In situ synthesis of orange rutile ceramic pigments by non-conventional methods
Ceramics International, 2010
Different precursor-mixtures of orange Cr,Sb-TiO 2 ceramic pigment have been obtained by non-conventional methods (heterogeneous ammonia coprecipitation, urea homogeneous coprecipitation, PECHINI polyester method and an original aqueous-organic coprecipitation method in water-diethylenglycol medium) in order to produce in situ the pigment through the ceramic body firing. The pigmenting performances of powders were appraised in two cases: (a) as ceramic pigment for glazed porcelain stoneware and (b) as ceramic inks for screen printing of porcelain stoneware. Samples were characterised by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), UV-vis-NIR spectroscopy by diffuse reflectance method, CIE-L*a*b* colour parameters, BET specific surface area and crystallite size measured by the Scherrer method. The colouring performance of raw powders obtained by non-conventional methods in glazed porcelain stoneware improves that of the ceramic samples fired at 1100 8C used as reference. TEM observations indicate nanostructured powders with pigmenting performance depending on factors such as their specific surface area (BET), the crystalline phases detected by XRD (e.g. anatase-rutile presence) and their crystallite size (Scherrer measurements). Ammonia coprecipitated samples, both in water and in water-diethylenglycol medium without surfactant addition, or modified by the addition of sodium dodecyl sulphate as surfactant, stand out by their colouring performance.
Industrial Ink-Jet Application of Nano-Sized Ceramic Inks
Advances in Science and Technology, 2006
Ink-jet printing is becoming a leading technology for traditional ceramics, due to its capacity of reproducing highly resolved and customized images on tile surfaces. Nano-sized inks, produced by the polyol synthesis route, proved to fulfil the printing requirements, tailoring their chemico-physical properties (e.g. viscosity, surface tension) on industrial ink-jet devices, so representing a major breakthrough in the quadrichromy process.
Au–Ag nanoparticles as red pigment in ceramic inks for digital decoration
Dyes and Pigments, 2012
Novel pigments, consisting of AueAg mixed nanoparticles, were developed for digital decoration by inkjet printing of ceramic wares. Special attention was paid to set up a microwave assisted synthesis route, with a low environmental impact, easily transferable to large-scale production. Several suspensions, based on Au, Ag and AueAg mixed nanoparticles were prepared, trying to get a core-shell assemblage, and the synthesis parameters like metal concentration, Ag/Au ratio, time, temperature and chelating agent amount were optimized. The suspensions are stable over many months and a total reaction yield, assessed by ICP-AES analysis, was achieved. Particle size, shape, composition and optical properties were measured by DLS, TEM-EDS, XRD and UVeVIS spectroscopy. The so-prepared inks were applied on ceramic tiles simulating the ceramic process and the colour performance, assessed by colourimetry, were expressed in the CIELab parameters.