化学共沉淀法制备陶瓷色料研究进展

综述了化学共沉淀法制备陶瓷色料工艺原理及流程,讨论了传统固相法制备陶瓷色料与化学共沉淀法制备陶瓷色料的优缺点,重点介绍了化学共沉淀法制备固溶体型陶瓷色料与包裹型陶瓷色料及其包裹模型,展望了化学共沉淀法的应用前景与研究方向。     

Use of the Precipitation Method in the Synthesis of Ceramic Pigments

The results of the synthesis of ceramic pigments using coprecipitation of hydroxides and difficultly soluble salts of multivalent metal ions are described. The specifics of the coprecipitation process and the effect of various factors on the production of the initial precipitates for subsequent synthesis of ceramic pigments are analyzed. The technology of pigment production is described. __________ Translated from Steklo i Keramika, No. 6, pp. 37 – 39, June, 2005.     

Nanocrystalline Ceramics Based on the ZrO2–HfO2–Y2O3 System

The formation of nanopowders of cubic solid solutions in the ZrO₂–HfO₂–Y₂O₃ system is investigated using the coprecipitation method. Conducting ceramic materials are prepared from the powders at 1450°C.     

Effect of the milling process on the properties of CoFe2O4 pigment

In this study, CoFe₂O₄ pigments were synthesised using both co-precipitation and conventional ceramic methods. Pigment particles prepared using the conventional ceramic method were subsequently milled to submicron size. The effects of the solvent, dispersant and milling type in the milling process were investigated. This study showed that planetary milling in a diethylene glycol (DEG) medium with sodium tripolyphosphate (STPP) was an effective method for producing submicron-sized pigment powders from pigments synthesised using the conventional method. With this method, submicron-sized pigment particles (approximately 190 nm) were obtained after milling for 4 h. Planetary milling was more efficient in reducing particle size compared to attrition milling. Co-precipitated pigment had a more intense black colour, due to the nanoscale particle size (<100 nm). However, conventional ceramic pigments also had an adequately intense black colour that increased after milling compared to unmilled conventional pigments. When considering production of industrial scale submicron-sized pigments, the milling of these pigments to submicron size can be a good alternative method for the production of ink colourants.     

Synthesis of CoAl2O4/Al2O3 nanoparticles for ceramic blue pigments

The demand for pigments for industrial ceramic ink-jet printing is increasing steadily. The main challenge is the availability of ceramic pigments comprised of small-sized particles in order to avoid clogging of the printer head nozzle. This work presents a novel way to prepare ceramic blue pigment as a shell/core structure of CoAl₂O₄/Al₂O₃ nanoparticles through a simple and low-cost process. In this process, the colour tone of nano-pigment can be tuned by the selection of the cobalt precursor/Al₂O₃ ratio and calcining temperature.     

Eu3+ -Nd2O3 blue pigmented solid solutions

Abstract

Usually, Nd₂O₃ shows a polymorphism based on the hexagonal Ln₂O₃ A type and cubic Ln₂O₃ C type structures, which have coordination numbers of 7 and 6 respectively. The Nd³⁺ (4f²) ion in an octahedral environment produces a reddish shade. In the present study, Eu_xNd_2-xO₃ compositions were prepared by ceramic and coprecipitation (from chloride solution) methods using several flux agents. Using the ceramic route, Nd₂O₃ C type structure was detected and the samples were colourless, but using coprecipitation, NdOCl crystallised from an amorphous coprecipitate at low temperature, developing the unusual monoclinic EuNd₂O₃ B type doped polymorph which is blue in colour. When enamelled using a conventional industrial tile glaze, these blue coprecipitated samples gave L*a*b* = 75/1/-11 in the CIE colour convention. Samples were characterised by X RD, U V-V-NIR spectroscopy, and SEM-EDX techniques.     

Production of Pigments with a Perovskite-Like Structure Based on Nickel Titanate by the Precipitation Method

The possibility of producing ceramic pigments based on the NiO – TiO₂ system by hydroxide coprecipitation from aqueous salt solutions is investigated. The synthesized pigments have good chromophore parameters and are stable up to a temperature of 1200°C. Practical recommendations are made.     

The influence of Ca2+ and Zn2+ doping on the development of sustainable pigments based on GdFeO3 perovskite: From a reddish colour towards a pure black

Black pigments are very commonly used and arouse widespread interest in the ceramic industry. Nevertheless, these pigments contain toxic elements that are detrimental to human health. In view of this, the present work is focused on the development of sustainable black pigments prepared by a coprecipitation method at 1200 °C. Samples with the nominal formula (Gd_1–xCa_x)(Fe_0.95Zn_0.05)O_2.975–x/2 (x = 0.00, 0.05, 0.10) showed single-phase orthorhombic perovskite. The presence of dopants played an important role in the reduction of Fe³⁺ to Fe²⁺ and caused different local distortions in the structure which explained the final black colouration of these pigments in comparison with the red GdFeO₃ sample. The loss of symmetry and the increase in the number of d-d transitions of iron may explain the aforementioned changes. Co-doped pigments reached low C* values, improving on the purest black colour obtained in a commercial black ceramic pigment, which contains toxic elements. In addition to presenting good NIR solar reflectance values of up to 8%, the final colours of these pigments were also stable after their application in a commercial transparent glaze at 1080 °C that could be used for tiles.     

Flame spray pyrolysis synthesis of ceramic nanopigments CoCr2O4: The effect of key variables

Spinel structure CoCr₂O₄ was synthesized by the non-conventional method flame spray pyrolysis (FSP) and the traditional route solid state reaction, where the optical properties were evaluated. The influences of FSP conditions as pressure of dispersion air and ceramic load of the solution over optical properties were evaluated using a 2² full factorial design with one replica. The final products were applied in ceramic glazes to evaluate pigmenting power. Powders were characterized by X ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis-NIR spectroscopy and Colorimetry. Results show that ceramic pigments obtained by FSP have highest percent reflectance and brightness than solid state reaction powders; nevertheless, both pigments are adequate to ceramic application. Besides, experiments showed that ceramic load of the starting solution have a strong influence over particle properties.     

Characterization of blue CoAl2O4 nano-pigment synthesized by ultrasonic hydrothermal method

Nano-sized CoAl₂O₄ pigments, which have received significant attention as a coloring agent in glaze and bulk tile compositions, were successfully synthesized by substituting mechanical stirring during hydrothermal process with ultrasonic irradiation. Difference in physicochemical and optical properties of the CoAl₂O₄ pigments prepared by an ultrasonic-assisted-hydrothermal method was characterized using simultaneous thermo-gravimetric and differential thermal analysis (TG–DTA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance spectroscopy, CIELAB colorimetric analysis, and testing in ceramic glazes and bodies. The ultrasonic-assisted CoAl₂O₄ pigments present a narrow particle size distribution with vivid blue color, and better thermal stability, allowing their use for ceramic inks processed at high temperature. Application of ultrasonic irradiation during the hydrothermal process produces nano-sized powders with better physicochemical and optical properties.     

Ceramic pigments obtained by sol-gel techniques and by mechanochemical insertion of color centers in Al2O3 host matrix

Nanocrystalline pigments for ceramic glazes have been obtained by mechanochemical insertion of Fe and Ti in an α-Al₂O₃ host matrix (Fe and Ti oxides were reduced by high energy milling with metallic Al with subsequent formation of additional Al₂O₃ by oxidation of Al(0)). The powders have been characterized by X-ray diffraction, laser granulometry and by surface area and porosity measurements. Sol-gel techniques have also been used in order to obtain pigments with pure Al₂O₃ and Cr or Fe/Ti-doped Al₂O₃. Pigments have been prepared using Al(III)-alkoxides or Al(III)-inorganic salts, obtaining products with different characteristics in the two cases. Pigments have been studied by X-ray diffraction, surface area and porosity measurements and by the analysis of electrochemical reactivity in aqueous suspensions. Coloring properties of pigments obtained by mechanomaking and by sol-gel techniques have been tested in ceramic glazes; their properties have also been analyzed by insertion in ceramic bodies for glazed gres (porcelain) technology.     

(Ce,Y)-ZrO2陶瓷的制备及性能研究

本文采用化学共沉淀法制备出均匀分散的(Y,Ce)-ZrO2微粉,通过适当工艺制备出复合稳定的ZrO2陶瓷.并采用X-射线衍射分析、扫描电镜及能谱分析研究了该样品的机械性能与相组成和微观结构的关系.结果表明:采用本工艺可制得致密度和机械性能较好的陶瓷制品,材料机械性能的提高可归结为微裂纹增韧、相变增韧和晶粒拔出效应的综合.     

Pb(Zr0.53Ti0.47)O3陶瓷超细粉体制备及分散研究

用化学共沉淀法合成了陶瓷Pb(Zr0.53Ti0.47)O3超细粉体,以聚乙二醇(PEG)为分散剂对所得粉体进行分散。通过X衍射、扫描电镜分析,研究了合成条件和煅烧温度对PZT粉体性能的影响。结果表明,随着煅烧温度的升高,PZT超细粉晶化度提高,一次晶粒尺寸增加,而二次粒子尺寸却减小。当分散剂分子量为10000,用量为1%时,得到分散良好的超细粉体。测定了用合成的粉体烧结的PZT陶瓷的压电性能。     

Carbon monoxide hydrogenation on Fe2O3/ZrO2 catalysts

Fe₂O₃/ZrO₂ catalysts prepared by impregnation and coprecipitation methods were used for catalytic hydrogenation of CO. It was shown that the structure, reduction behavior of iron species, and catalytic properties of the catalysts were obviously affected by the preparation methods. For the Fe₂O₃/ZrO₂ catalyst prepared by the impregnation method, the Fischer-Tropsch catalytic activity and the selectivity to light olefins were much higher than those of the corresponding catalyst prepared by the coprecipitation method, the formation of methane was suppressed and the selectivity to light olefins was enhanced. Various intermediates formed during the successive steps of reduction of the catalysts were studied by using temperature-programmed reduction combined with in situ Mössbauer spectroscopy. The role of zirconia in the catalysts was discussed.     

MnFe2O4纳米晶体的制备及表征

本文分别采用低温共沉淀法、高温法和水热法制备MnFe2O4的纳米晶体。利用XRD、TEM和VSM对试样进行了表征。重点研究了低温共沉淀法的制备方法。通过对三种方法的对比分析,试验结果表明低温共沉淀法适宜制备小粒径的MnFe2O4。     

A strong ceramic in the Al2O3-ZrO2-Y2O3 system

Conclusions A highly dense ceramic based on the eutectic composition of the Al₂O₃-ZrO₂ system was obtained using 3 mole % Y₂O₃ addition. The ceramic has a fine-grained structure and high hardness and strength.Translated from Ogneupory, No. 2, pp. 8–10, February, 1987.     

Laser-quality Tm:(Lu0.8Sc0.2)2O3 mixed sesquioxide ceramics shaped by gelcasting of well-dispersed nanopowders

Tm³⁺-doped mixed sesquioxide transparent ceramics are attractive candidates for the generation of robust ~2.1 μm lasers. In this paper, laser-quality Tm:(Lu_0.8Sc_0.2)₂O₃ mixed sesquioxide ceramics were shaped for the first time by gelcasting of well-dispersed nanopowders, which were obtained using a modified coprecipitation method. The dispersibility of starting nanopowders was largely improved using alcohol-water solvent. The rheological properties of slurries were optimized for gelcasting. We also investigated the densification behavior of the gel-casted green compacts. In contrast to the dry-pressing route, it was found that gelcasting could yield more homogeneous and transparent ceramics. The optical in-line transmittance of the ceramic rod 12 mm in length was as high as 80.3% at 2090 nm. Upon pumping the ceramic rod by 796 nm diode laser, a 1.88 W CW laser at 2090 nm was acquired with a slope efficiency of 24.6% (with respect to the input pump power).     

Propylene metathesis over Re2O7/Al2O3-B2O3 catalysts

A series of alumina aluminum borate (AAB) with various Al/B molar ratios were prepared by the coprecipitation method. The supported rhenium oxide catalysts with various contents of Re₂O₇ were also prepared by the impregnation method with perrhenic acid. The catalytic activity and stability of Re₂O₇/AAB catalysts for the reaction of propylene metathesis were tested in a fixed-bed microreactor. It was found that Re₂O₇/AAB is more active, stable and regenerable than Re₂O₇/Al₂O₃ for propylene metathesis. The optimum Al/B molar ratio was found to be in the range of 4–10.     

Nd:Y2O3 Powder Synthesized by Low Temperature Calcination for Fabricating Transparent Ceramics

A precursor for Nd³⁺-doped Y₂O₃ powder was prepared by a coprecipitation method with (NH₄)HCO₃ as precipitant. The influence of fixed duration calcination at low temperature on the micromorphology of the powder, and the subsequent effect of sintering conditions on the transmittance of the resulting Nd³⁺-doped Y₂O₃ ceramic was systematically studied. The results show that the shape of the Y₂O₃ particles changes from acicular to flake-like by calcining for 2 h and increasing the calcination temperature, and that a sample sintered at 1983 K for 8 h after being calcined at 973 K for 2 h shows the highest transmittance. This example of transparent Nd³⁺-doped ceramic is a good candidate for solid-state lasers, IR windows, lamp envelopes, etc.     

B位离子共沉-煅烧法制备Ba(Mg1/3Ta2/3)O3微波陶瓷材料

采用钽镁共沉淀法制备ＭｇＴａ２Ｏ６粉体,然后与ＢａＣＯ粉体混合制备Ｂａ（Ｍｇ１／３Ｔａ２／３）Ｏ３（简称ＢＭＴ）微波陶瓷材料,成功地解决了ＴａＣｌ３溶解问题。对钽镁共沉条件和粉体热分解工艺与粉体的平均粒径和钽镁比例关系;ＢＭＴ陶瓷制备工艺与材料的微观结构和微波性能关系进行了研究,制备的ＭｇＴａ２Ｏ６晶相粉体平均粒径为０．３μｍ,最大与最小粒径比为５。制备的ＢＭＴ陶瓷的几乎不含ＢａＴａ２Ｏ６等杂相,