Ceramic Pigments Research Articles

Synthesis and Characterization of Hydrothermal Synthesized Ultra-Red CdS1−x Se x Pigment

Ultra-red pigment is in urgent need to enrich the colour range as well as to improve the quality of ceramic product. In this study, ultra-red CdS1−x Se x pigments (CP) were synthesized through hydrothermal technique. The effects of S/Se ratio on the structural and optical properties of CPs were investigated. CPs were characterized by XRD, ICP, SEM and UV-vis techniques. The colorimetric parameters of CPs were measured as also their band-gaps were estimated based on Tauc plot method. Furthermore, detailed formation mechanism of CdS1−x Se x has been elucidated. The results demonstrate that different compositions of CdS1−x Se x can be facilely obtained by adjusting the R value (starting S/Se molar ratio); when R is equal to 0.67 and 0.83, the prepared samples are CdS0.75Se0.25, when R is equal to 1.00, 1.17 and 1.33, the prepared samples are CdS0.571Se0.429. It is found that excessive S2− plays critical role in CdS1−x Se x formation. CP prepared with R=1.00 owns L*=44.69, a*=49.93, b*=22.66, implying an excellent red colour, which indicates potential use as an ultra-red ceramic pigment.

Dispersion stability analysis of copper sulphide nanoparticles in different medium

Nanoparticles (NPs) of covellite CuS have been synthesised using a modified polyol method at 160ºC - 165ºC without adding any extra surfactant. These NPs were charecterized by X-ray diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive Analysis of X-ray (EDAX), Zeta potential and Dynamic Light Scattering (DLS) techniques. XRD data and three Raman modes confirm P63/mmc space group and hexagonal crystal structure of CuS NPs. EDAX data of Cu:S was slight differed from nominal 1:1 ratio due to extra S taken in synthesis. FESEM images show sheet-like NPs. The zeta potential (ξ) data analysis shows that the stability of the NPs is dependent on the dispersion medium, with high stability observed above pH 8.93 in an acidic medium. At pH 10.95, a highest ξ value of -37.64 mV is recorded in de-ionized water (DIW), while the nanoparticles are found to be unstable in ethanol and propanol as dispersion mediums. According to the hydrodynamic diameter (HD) data, the particles tend to agglomerate more quickly in ethanol and propanol compared to DIW. These findings are expected to be useful in various applications such as pigments in paints, batteries, pharmaceuticals, ceramics, and waste water treatment.

Effects of Coloration of Spinel CoAl2O4 Cobalt Blue Pigments: Composition, Structure, and Cation Distribution

Cobalt blue ceramic pigments mainly consisting of CoAl2O4 are subject to the difficulty of color control. Here, a perspective is reported regarding research on the reasons for color change based on the control of the heat treatment and ratio of components. Macroscopically, the composition of pigment powders determines the color. Microscopically, the crystallite characters including size, cation distribution, and structure have an important effect on the color. The ingredient, structural, and color properties of the pigment powders are analyzed using thermo gravimetry–differential scanning calorimetry (TG–DSC), X-ray diffraction (XRD) measurement, Rietveld refinement, energy dispersive spectrometer (EDS), and colorimetry analysis. The color is proven to be associated with cation distribution, such as that of Co2+ and Co3+. It is indicated that high heating temperature, long heating time, and a large proportion of Al3+ can, respectively, induce the Co2+ and Al3+ in tetrahedral and octahedral sites.

The Chemical and Mineralogical Studies of Microsilica for Obtaining Silicate Materials

In this scientific work, the chemical and mineralogical properties of microsilica formed during the production of ferroalloy in the production of silicate materials at JSC “Uzmetkombinat” were studied. It has been established that the obtained results of the analysis confirm the technological feasibility of using microsilica in silicate materials, in particular for the production of glass, heat–insulating, oxide ceramic materials, as well as ceramic pigments.

Preparation, Chromatic Properties Analysis and Proportioning Optimization of Co-Cr-Fe-Based Black Pigment.

The utilization of Co-Cr-Fe-based black pigments bears considerable significance within the realm of commercial ceramic pigments, owing to their distinctive spinel structure, remarkable high-temperature stability, and exceptional chromatic attributes. This study delves into the synthesis of diverse black pigment configurations by employing the co-precipitation method, leveraging the interplay of these three metallic oxides. This investigation encompasses a comprehensive scrutiny of ion valences, crystal structures and parameters, colorimetric properties, and their interrelationships. The methodology integrates the response surface methodology (RSM) framework, using theoretical formulations to navigate the material ratios and elucidating the associations between the resultant compositions and color coordinate values, aligned with the CIE-Lab* colorimetric methodology. The derived predictive models yielded an optimized black pigment composition, characterized by heightened black intensity and a refined formulation.

Comparative Study of the Synthesis of a Red Ceramic Pigment Using Microwave Heat Treatment

In this study, a new red ceramic pigment has been developed within a perovskite structure, and microwave heat treatments have been applied. Those red ceramic pigments within the YAlO3 system doped with chromium with the nominal composition Y0.98Al0.98Cr0.04O3 were synthesized by traditional routes and alternative methods like coprecipitation. Also, heat treatment has been studied comparing a traditional electric and microwave kiln. Different flux agents have been incorporated to improve the synthesis reaction. Prepared pigments have been characterized by X-ray diffraction (XRD) as having a predominant phase of perovskite structure, which is responsible for the red shade, and a minority garnet phase that causes more brown colorations. Studies by Ultraviolet-Visible spectroscopy gave rise to a series of absorption bands that indicate the presence of Cr(III) in the octahedral position corresponding to perovskite and Cr(IV) corresponding to garnet in both the octahedral and tetrahedral positions. The perovskite phase is favored with the use of flux mix, corroborating the UV-visible results and being more pronounced in traditional high temperature thermal treatments. The coprecipitation route has been studied to increase the reactivity of the particles given their nanometric size; however, this reactivity favors a greater appearance of undesirable garnet phases with both types of flux. Scanning Electron Microscopy (SEM) micrographs offer information obtained from the secondary electrons of predominantly cubic crystalline phases with sizes between 1 µm and 2 µm in pigments synthesized via the traditional method and sizes less than 1µm together with the glassy phase in pigments synthesized via coprecipitation. Microwave thermal treatments have been studied, obtaining pigments with a majority structure of perovskite and garnet at lower temperatures and relatively short synthesis times. The feasibility of use in porous single-fired ceramic glazes has been studied, whose chromatic coordinates have been collected using an Ultraviolet-Visible Spectrophotometer based on the CIEL*a*b* system.

Keda buys 40% stake in Shandong Sinocera[StQuote]s ceramic pigments business

Keda buys 40% stake in Shandong Sinocera[StQuote]s ceramic pigments business

SrMn1-xFexO3-δ (x = 0–1) black ceramic pigment: Synthesis, color properties, and application

In this work, SrMn1-xFexO3-δ (x = 0–1) black ceramic pigments were synthesized by the solid-state method. The research explores the influence of calcination temperature and iron ion doping on the color properties of the pigments. Furthermore, the potential applications of SrMn1-xFexO3-δ pigments in ceramic glaze and heat-absorbing materials are also discussed. The findings reveal that the synthesized SrMnO3 pigment exhibits the lowest L*-value (22.30) at 1100 °C, although it displays a slight blue hue. To optimize the color properties of the SrMnO3 pigment, iron ion doping is employed. When the doping level of iron ions is 50 mol.% (i.e., x = 0.5), the L*-value of the SrMn0.5Fe0.5O3-δ pigment calcined at 1000 °C significantly decreases to 19.77, while the a*- and b*-values approach 0, resulting in a pure black color. This is attributed to the high surface roughness, low band gap energy, and substantial oxygen vacancies present in the SrMn0.5Fe0.5O3-δ pigment. The tinting mechanism of the SrMn1-xFexO3-δ pigment in the ceramic glaze is classified as "ion tinting", wherein the glaze color relies on the concentrations of Mn and Fe ions. When the pigment content reaches 36 wt%, the L*-value of the glaze drops to 4.94, showing a deep black shade. Additionally, the SrMn0.5Fe0.5O3-δ pigment exhibits excellent sunlight absorption capabilities, with a near-infrared reflectance (R*) of only 5.04%. This research presents a black ceramic pigment with various advantages, such as simplified processing, affordability, environmental friendliness, and exceptional color performance.

Effect of micronisation on colour and optical properties of ceramic colourants for inkjet printing

The advent of inkjet printing (IJP) as the main used decoration technique for ceramic products has changed the technological requirements for pigments and the way they are obtained. To meet IJP and durability requirements, it is necessary to micronise the colourants to achieve particles smaller than 1 μm (median particle diameter d50 ∼300 nm). The high-energy milling process induces microstructural changes that affect the colour properties. In order to understand the effect of particle size reduction on chromatic properties, an in-depth study was carried out by simulating the industrial milling process on a pilot scale. The effect of micronisation was investigated for four ceramic pigments (yellow zircon, brown spinel, pink malayaite, and green eskolaite) and one dye (blue olivine) by UV–vis–NIR optical spectroscopy (DRS), chromatic coordinates and XRPD analyses (Rietveld method). This study was carried out on the colourants both as they were and mixed with glass, reproducing the industrial firing process. The results obtained led to the definition of the main aspects responsible for the colour evolution derived from the milling process.

High NIR Reflectance and Photocatalytic Ceramic Pigments Based on M-Doped Clinobisvanite BiVO4 (M = Ca, Cr) from Gels.

Clinobisvanite (monoclinic scheelite BiVO4, S.G.I2/b) has garnered interest as a wide-band semiconductor with photocatalyst activity, as a high NIR reflectance material for camouflage and cool pigments and as a photoanode for PEC application from seawater. BiVO4 exists in four polymorphs: orthorhombic, zircon-tetragonal, monoclinic, and scheelite-tetragonal structures. In these crystal structures, V is coordinated by four O atoms in tetrahedral coordination and each Bi is coordinated to eight O atoms from eight different VO4 tetrahedral units. The synthesis and characterization of doped bismuth vanadate with Ca and Cr are studied using gel methods (coprecipitated and citrate metal-organic gels), which are compared with the ceramic route by means of the UV-vis-NIR spectroscopy of diffuse reflectance studies, band gap measurement, photocatalytic activity on Orange II and its relation with the chemical crystallography analyzed by the XRD, SEM-EDX and TEM-SAD techniques. The preparation of bismuth vanadate-based materials doped with calcium or chromium with various functionalities is addressed (a) as pigments for paints and for glazes in the chrome samples, with a color gradation from turquoise to black, depending on whether the synthesis is by the conventional ceramic route or by means of citrate gels, respectively; (b) with high NIR reflectance values that make them suitable as fresh pigments, to refresh the walls or roofs of buildings colored with them; and (c) with photocatalytic activity.

Eco-friendly polyfunctional ceramic pigments: an approach

Purpose The purpose of this study is the synthesis and characterization of a CMYK palette (cyan of Cr-BiVO4, magenta of Pr-CeO2, yellow of Bi-(Ce,Zr)O2 composite and black of YMnO3) as an eco-friendly polyfunctional palette that combines (a) high near-infrared reflectance (cool pigments) that allows moderate temperatures in indoor environments and the urban heat island effect; (b) photocatalytic activity for the degradation of organic contaminants of emerging concern of substrates in solution (such as Orange II or methylene blue) and gaseous (NOx and volatile organic compounds such as acetaldehyde or toluene); (c) X-ray radiation attenuators associated with bismuth ions; and (d) biocidal effect combined with co-doping with bactericidal agents. Design/methodology/approach Pigments were prepared by a solid-state reaction and characterized by X-ray diffraction, diffuse reflectance spectroscopy, photocatalytic activity over Orange II and scanning electron microscopy. Findings The behaviour of the proposed palette was compared to that of a commercial inkjet palette, and an improvement in all functionalities was observed. Social implications The functionalities of pigments allow the building envelope and indoor walls to exhibit temperature-moderating effects (with the additional effects of moderating global warming and increasing air conditioning efficiency), purification and disinfection of both indoor and outdoor air, and radiation attenuation. Originality/value The proposed palette and its polyfunctional characterization are novel.

Evaluation of Microwave Synthesis of Ceramic Pigments Based on In Situ Dielectric Characterization.

The application of microwave technology for efficient and environmentally friendly synthesis of ceramic pigments is a successful and rapidly evolving area of research. However, a clear understanding of the reactions and their relationship with the material absorbance has not been fully achieved. The present study introduces an in situ permittivity characterization technique, which serves as an innovative and precise tool for assessing the microwave synthesis of ceramic pigments. Several processing parameters (atmosphere, the heating rate, raw mixture composition and particle size) were evaluated by studying the permittivity curves as a function of temperature to elucidate their effect on the synthesis temperature and the final pigment quality. The validity of the proposed approach was verified through correlation with other well-known analysis techniques, such as DSC or XRD, providing valuable information about the reaction mechanisms and the optimum conditions for the synthesis process. In particular, changes in permittivity curves were linked, for the first time, to undesired metal oxide reduction at too-high heating rates and could be used to detect pigment synthesis failures and ensure product quality. The proposed dielectric analysis was also found to be a useful tool for optimizing raw material composition for the microwave process, including the use of chromium with lower specific surface area and flux removal.

Low-temperature synthesis of ultrafine Cr,Mg-codoped Al2TiO5 nanocrystals as high-temperature green ceramic pigment

Tialite (Al2TiO5) is attracting as a high-temperature ceramic host matrix, but the decomposition of Al2TiO5 at 780–1280 °C is a serious obstacle for practical application. Herein we prepared successfully ultrafine Cr,Mg-codoped Al2TiO5 green ceramic pigment with the nanocrystal sizes less than 50 nm and high-temperature stability of up to 1200 °C via nonhydrolytic sol-gel (NHSG) method followed by heating treatment of 750 °C. The effects of Cr and Mg content on phase composition, crystal structure, thermal stability and color property were well investigated. The optimum Cr,Mg-codoped Al2TiO5 pigment with 20 mol% Mg and 6 mol% Cr exhibited an excellent green color (L* = 76.94, a* = −9.62, b* = 14.17), which can be reasonably maintained in exposed air by a heating treatment at 1200 °C for 10 h or in transparent ceramic glaze at 1200 °C for 30 min. These enhanced performances were mainly attributed to synergistic effect of Cr and Mg doping, which hindered the tendency of Al2TiO5 toward decomposition, indicative of its potential application in high-temperature ceramic decoration.

The colors of the empire: Assessing techno-decorative innovations in local, hybrid and intrusive ceramic pigments within the Wari interaction spheres, Peru

Ancient empires developed diverse strategies of political and cultural domination in their conquered territories. One such strategy involved introducing imperially branded goods that reinforced a legitimizing ideology. The appearance of intrusive styles may be an indicator of political dominance; however, the introduction of new technologies is a stronger indicator of interpersonal engagement between people in the empire’s core and dominated regions. In this paper, we specifically focus on innovations in colors, pigments, and decoration of intrusive, local, and hybrid ceramic styles resulting from the interaction between the Wari Empire (600–1050 CE) of the Central Andes and local societies from the north and south coast of Peru. These innovations can be documented long after the Wari influence faded in each region. By integrating archaeological and archaeometric perspectives, we examine techno-decorative innovations among locally produced pottery within the imperial interaction spheres. This paper presents and compares the results of chemical and mineral analyses conducted on samples of pigments on decorated ceramics from the Valleys of Jequetepeque, Nasca, and Moquegua. Results indicate that Wari could have directly promoted the circulation of specific ceramic pigments that guaranteed a particular “Wari experience of color.” We argue that an inter-site approach to the study of colors, pigments, and decoration can better contribute to the understanding of politics and ceramic production relationships, religious syncretism, and cultural change in the Andean past.

Cobalt-containing diopside pigments based on granulated blast furnace slag

PurposeThe purpose of this study was to the low-temperature synthesis of cobalt-containing diopside pigments based on granulated blast furnace slag and to study the characteristics of the mineral formation processes, changes in the structure and colour indices.Design/methodology/approachSynthesis of cobalt-containing diopside pigments based was carried out by the directional formation of the mineralogical composition with the introduction of part of the components using granulated blast-furnace slag.FindingsIt has been established that the formation of the diopside phase in pigments containing blast-furnace slag as the main component proceeds at low temperatures (1,100°C–1,150 °C). The colour of diopside pigments is formed because of the isomorphic substitution of Si4+ ions for Al3+ ions and Mg2+ ions for Co2+ ions. It is expedient to add CoO in an amount of 0.9 mol (18 Wt.%) into the composition of diopside pigments based on blast-furnace slag to obtain defect-free violet glazes.Practical implicationsThe developed diopside pigments enable obtaining of high-quality violet glazes for ceramics. The application of the obtained results can significantly reduce the consumption of traditional raw materials in the composition of silicate ceramic pigments, as well as reduce their firing temperature.Originality/valueCalcium, magnesium and silicon oxides are the main components of blast-furnace slag. In addition, granulated blast furnace slag is mainly represented by the glassy phase, which determines its high activity during the firing process. These factors are prerequisites for using the blast-furnace slag as a valuable substitute for chemically pure or natural raw materials in silicate pigments and reducing their firing temperature.

A review of various ceramic pigment preparation and characterization methodologies for applications

A review of various ceramic pigment preparation and characterization methodologies for applications

Twin-screw extrusion synthesis of low-cost cobalt ferrite ceramic pigments using natural mixed-dimensional palygorskite clay

Due to the disadvantages of traditional solid-phase and liquid-phase methods for preparation of mixed metal oxide ceramic pigments, it is indispensable to develop a green, clean, low-cost and continuous preparation technology. In this study, the low-cost and high-performance cobalt ferrite ceramic pigments were facilely prepared based on natural mixed-dimensional palygorskite clay by a continuous mechanochemical method using twin-screw extrusion. The incorporation of the mixed-dimensional palygorskite clay effectively improved the agglomeration of pigment nanoparticles and decreased the production cost. The hybrid pigments presented the optimal color properties (L* = 17.16, a* = 1.07, b* = 3.58 and C* = 3.74) when the cobalt ferrite content, calcination temperature and time were 60 wt%, 1100 °C and 90 min, respectively. Furthermore, the as-prepared hybrid pigments exhibited excellent chemical and thermal stability and biocompatibility, the mass tone and hiding power of the hybrid pigments were superior to the commercial cobalt black pigments, thus the obtained hybrid pigments could be served as an eco-friendly underglaze pigment for coloring of ceramic embryo body with good color saturation. Beyond all doubt, this study will provide a promising strategy for continuous cleaner preparation of low-cost cobalt ferrite ceramic pigments.

Zircon ceramic pigments synthesized from waste product by petroleum industry

Zircon ceramic pigments synthesized from waste product by petroleum industry

Synthesis and color properties of MnTiO3 black ceramic pigment

In this paper, MnTiO3 powder has synthesized by solid-state method, and its color properties were also investigated. Research indicates that the L*-value of the prepared MnTiO3 powder was only 25.85, showing a pure and deep black hue, which indicates that MnTiO3 can be used as a black ceramic pigment and coating. The color mechanism of MnTiO3 pigment is attributed to the 6A1g→4A1g and 6A1g→4T2g crystal field transition of octahedral Mn2+ site. Besides, the MnTiO3 pigment exhibited outstanding tinting performance in ceramic glaze. The L*-v alue of the glaze sample with 8 wt% MnTiO3 pigment added was only 11.44, which is the minimum value reported in the literature. Moreover, the MnTiO3 pigmented coating shows an excellent solar energy utilization performance. This work demonstrates the promising application of MnTiO3 pigment in ceramic decoration and solar absorber.

Development of Red Ceramic Pigments with Perovskite Structure Prepared through a Traditional Route

Solid solutions of ceramic pigments of red shade have been synthesized based on YAlO3 perovskite structure doped with chromium by means of conventional synthesis; that is, the “ceramic route”. To optimize this synthesis, an emphasis has been made on the study of stoichiometry, calcination conditions and mineralizer incorporation. Various studies have demonstrated the high stability of perovskite structures, which ensures stable coloration at high temperatures. This is a highly important factor in the ceramic sector, given the scarcity of red glazes functional at temperatures close to those required of porcelain stoneware and their environmental constraints. Such a limitation makes it impossible in the European community to manufacture using toxic materials such as Se and Cd (cadmium sulfoselenide) that offer interesting colors at low temperatures. Pigments have been synthesized within the Y1−xCrxAlO3, YCrxAl1−xO3 and Y1−xAl1−yCrx+yO3 chromium-doped systems in molar ratios between n = 0.01 molar and n = 0.10 molar. The pigments obtained have been characterized by X-ray diffraction to identify the crystalline phases responsible for the shade; that is, the formation of the perovskite crystalline structure YAlO3 responsible for the red shade, together with lateral phases of garnet Y3Al5O12 of lower intensity. Visible ultraviolet spectrophotometry shows absorption bands corresponding to Cr(III) in octahedral position and the appearance of Cr(IV) in both octahedral and tetrahedral positions. The morphology of the samples was studied using a scanning electron microscope, obtaining information from the secondary and back scattered electrons. The viability of its use in ceramic glazes was verified after applying them mixed at 4% by weight in a glaze to an industrial porous single-firing cycle, collecting the L*a*b* chromatic coordinates using a visible ultraviolet spectrophotometer based on the CIE L*a*b* system, giving rise to red colorations.