Effect of Sr^2+ and Dy^3+ co-doping on coloration and temperature stabilization of a γ-Ce2S3 red pigment

In this paper,a Sr^2+and Dy^3+co-doped γ-Ce2S3 red pigment was synthesized via a combination of coprecipitation and sulfurization processes.Mixed oxide was prepared by presintering the coprecipitates,(Ce,Sr,Dy)CO3,followed by high-temperature sulfurization under a CS2 atmosphere.The effects of the sulfurization temperature,time,and doped proportion on the phase composition,color performance and temperature stability of γ-Ce2S3 were systematically studied.The results show that a stable γ-Ce2S3 red pigment can be obtained through Sr^2+and Dy^3+co-doping at 730℃ for 200 min.The diffraction peaks of all the samples shift to higher 2θ values with increasing doping proportion,indicating that part of the Dy^3+species enter the lattice and form a solid solution.The band gap of the samples remains practically constant at 2.01-2.04 eV,which causes their red color.The best red-color quality(L*=37.13,a*=34.77,b*=29.44) is achieved when the pigment has a Dy^3+/Ce^3+molar ratio of 0.15,and the material maintains its excellent red color(L*=31.49 a*=30.94 b*=25.33) after being heated at 410℃ for 30 min.

γ-Ce_2S_3型红颜料的制备研究

描述了以工业纯的二氧化铈为原料 ,以无水碳酸钠为添加剂 ,硫磺、氩气和氢气为控制气氛 ,采用两段法制备红颜料硫化铈的新工艺 ,研究了掺钠量和合成温度对产品性能的影响规律及后处理工艺。实验结果表明 :nNa∶nCe在 0 . 2～ 0 . 3范围内 ,产品硫化铈颜色深红 ;适宜的烧成温度范围为 10 0 0～ 115 0℃ ;氟处理试验结果表明 ,当NH4 F溶液浓度为 5 0～ 10 0g·L- 1 时 ,可明显提高红颜料硫化铈的鲜艳程度 ,产品红颜料硫化铈的色度坐标可达到 :L 3 7～ 40 ,a 5 4～ 5 7,b 3 9～ 42。

碱金属添加剂Na^+对γ-Ce_2S_3红色颜料合成及颜色的影响

适应无毒性以及耐温、耐候、耐腐蚀性能好的要求,γ Ce2S3作为无机红色颜料有着广阔的应用前景。本文较为详细的阐述了两段法制备γ Ce2S3的实验工艺,实验结果表明原料中添加适量的碱金属Na+可以降低β Ce2S3向γ Ce2S3的转变温度,可在较低的温度下获得γ Ce2S3纯相;生成物含有Na+同时能够改变颜料的色调,颜料由红色向橘红转变。碱金属Na+占据γ Ce2S3的金属原子空位和部分替代γ Ce2S3中金属原子可提高γ Ce2S3的稳定性。

γ-Ce_2S_3的研究进展

详细阐述了在低温下稳定γ-Ce2S3的不同方法,添加碱金属、碱土金属、重镧系、碳或硅,磷酸盐、硼酸盐、少量的钒酸盐或砷酸盐前驱物。说明了磷酸盐和碱金属为更理想的添加剂。同时指出对γ-Ce2S3进行氧化物包覆处理可以提高其热稳定性以拓展其应用领域。制备出氧化物完全包覆的γ-Ce2S3以及使用液相法制备γ-Ce2S3是未来的发展方向。

固体超强酸S_2O_8^(2-)/ZrO_2-Ce_2O_3催化合成乙酸苄酯的研究

用新型稀土复合固体超强酸催化苯甲醇与乙酸的酯化反应合成了乙酸苄酯 .实验结果表明 :S2 O2 -8/ZrO2 -Ce2 O3 具有较高的催化活性 .考察了苯甲醇与乙酸摩尔比、催化剂用量、反应温度、反应时间、带水剂环己烷用量对酯收率的影响 .在适宜反应条件下乙酸苄酯的收率可以达到 89.3% .该催化剂易于回收且可重复使用 ,具有良好的活性稳定性 .

水热法制备γ-Ce_2S_3@ZrO_2包裹型大红色料

以γ-Ce_2S_3和Zr(SO4)2·4H2O为原料,采用水热法合成了核壳结构的ZrO_2包裹的γ-Ce_2S_3大红色料(记为γ-Ce_2S_3@ZrO_2),研究了水热体系的p H值、水热助剂、水热时间、水热温度以及水热次数对色料结构和形貌的影响。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电子显微镜(TEM)和色度计对样品进行了表征。研究结果表明:调节溶液的p H值为13.0,以C2H3Na O2为助剂,180℃下水热反应18 h,重复水热3次,可获得抗酸腐蚀性能良好、色泽鲜艳的γ-Ce_2S_3@ZrO_2包裹型大红色料。

水解法制备SiO2包裹γ-Ce2S3色料及其耐酸性研究

本文以市售大红色料γ-Ce_2S_3为原料,正硅酸乙酯(TEOS)为硅源,采用水解法制备了SiO_2包裹γ-Ce_2S_3色料,采用X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电镜(FE-SEM)、能谱仪(EDS)、傅立叶红外光谱(FTIR)等技术对色料进行了表征。研究结果表明,在TEOS/H_2O质量比为1∶20、Ce/Si摩尔比为3∶1、水解温度为45℃、水解用纯水滴加速率为0. 3 m L/min的条件下,可获得均匀致密的无定型二氧化硅(Si O2·x H2O)包裹层,其厚度为100 nm左右,包裹色料仍保持鲜艳的红色,其色度L*、a*和b*值分别为26. 82、35. 53和29. 60;该条件下所得包裹色料的耐酸性最佳,未包裹色料浸泡于1 mol/L的盐酸中半分钟之内已失去红色,而该色料浸泡2 h其呈色仍没有明显变化。

γ-Ce_2S_3大红色料表面附着ZnO及对H_2S释放的影响

以市售大红色料γ-Ce_2S_3为原料,六水合硝酸锌(Zn(NO_3)_2·6H_2O)为锌源,无水碳酸钠(Na_2CO_3)为沉淀剂,醇水混合溶液为反应介质,采用非均相沉淀法在γ-Ce_2S_3色料表面附着一层ZnO,研究含Zn前驱体在色料颗粒表面附着形态及附着ZnO后对色料受热后H_2S释放的影响。研究结果表明:以乙醇与水混合溶液为反应介质,沉淀离子采用同步滴加方式,滴加速度0.3 mL/min,Zn与γ-Ce_2S_3的摩尔比为0.2时,300℃热处理30 min能够在γ-Ce_2S_3颗粒表面均匀附着一层ZnO,且色料仍保持鲜艳的红色,其色度L*、a*和b*值分别为34.17、33.10和22.80;表面附着ZnO后对H_2S的释放有明显的抑制作用,色料在350℃保温10 min,H_2S释放浓度由未附着ZnO的4.21 mg/m3降至0。

Ca2+离子掺杂对γ-Ce2S3合成温度及热稳定性的影响

以CeCl3·7H2O、CaCl2·2H2O和C2H2O4·2H2O为原料,在制备钙铈氧化物前驱体基础上,再以Ar气为载气、CS2为硫源对钙铈氧化物前驱体进行硫化合成Ca2+掺杂的γ-Ce2S3色料。通过X射线衍射(XRD)、紫外-可见漫反射光谱(UV-Vis)及差热-热重分析(TG-DTA)等技术手段表征了色料的结构和性能。结果表明,Ca2+掺杂能够明显降低γ-Ce2S3的合成温度,当n(Ca2+):n(Ce3+)≥0. 16时,在900℃硫化150 min即可获得纯相的γ-Ce2S3,与不掺杂时合成γ-Ce2S3的温度相比降低了300℃左右。同时,Ca2+掺杂能够提升γ-Ce2S3的抗氧化能力,当n(Ca2+):n(Ce3+)=0. 64时,氧化放热峰的温度由不掺杂时的490. 6℃提高至541. 0℃。

Sr^(2+)掺杂对γ-Ce_2S_3色料的呈色性能影响

以Ce(NO_3)_3·6H_2O、Sr(NO_3)_2、(NH_4)_2CO_3为原料,采用共沉淀法制得(Ce,Sr)CO_3沉淀物并经1000℃保温2 h煅烧后制得锶铈氧化物,锶铈氧化物在900℃采用CS_2硫化150 min制得Sr^(2+)掺杂的γ-Ce_2S_3色料。研究了Sr^(2+)掺杂量对γ-Ce_2S_3的呈色的影响。采用X射线衍射分析(XRD)、色度仪、紫外可见光谱(UV-vis)对硫化产物进行表征分析。研究结果表明:当掺入Sr^(2+)时,纯相γ-Ce_2S_3在900℃便能合成;Sr/Ce摩尔掺杂比为0.05～0.7时,Sr^(2+)能进入了晶格形成固溶体;随着Sr^(2+)掺杂量的增加,γ-Ce_2S_3颜料的禁带宽度从2.02 eV增加2.28 eV,其颜色由红色逐渐过渡到黄色。

γ-Ce2S3大红色料的研究进展

γ-Ce2S3是一种无毒环保型无机大红色料,因其色泽鲜艳、遮盖力强、优异的抗紫外能力,被认为是目前广泛应用的CdSe1-xSx大红色料的最佳替代品。但其在350℃下就会被氧化分解而失去红色,导致其很难在高温领域获得应用。从γ-Ce2S3的晶体结构出发,详细综述了近年来γ-Ce2S3的制备方法、离子掺杂及包裹对γ-Ce2S3的合成、晶体结构、色度以及热稳定性等性能的影响,指出了研究中存在的问题,提出了未来的研究方向。

水解法和水解-水热法制备γ-Ce2S3@SiO2包裹色料的研究

以工业纯γ-Ce_2S_3大红色料为研究对象,以正硅酸乙酯(TEOS)、氨水(NH_3·H_2O)、CTAB和无水乙醇为原料,研究水解法和水解-水热法在不同醇水比条件下制备SiO_2包裹γ-Ce_2S_3色料(记为γ-Ce_2S_3@SiO_2)效果和性能的影响。研究发现水解-水热法制备的γ-Ce_2S_3@SiO_2色料包裹效果优于水解法,当醇水比为7∶1时,包裹色料表面的SiO_2包裹层厚度适中,更致密,包裹色料经550℃热处理后仍然能够保持一定的红度,a*达到22.16。包裹后色料的抗氧化温度从350℃左右提高到758℃。

Ba^(2+)-Nd^(3+)共掺杂型γ-Ce_(2)S_(3)大红色料的制备及其性能研究

采用共沉淀法并根据摩尔比n(Ba)/n(Ce_(1-x)Ndx)=0.1(x=0,0.01,0.03,0.05,0.07,0.10)制备Ba^(2+)-Nd^(3+)共掺杂的γ-Ce_(2)S_(3)(缩写为γ-[Ba,Nd]-Ce_(2)S_(3))大红色料。以CS2为硫源在850℃下煅烧150 min,所得硫化产物为γ-[Ba,Nd]-Ce_(2)S_(3)(简写为S.Ndx),系统研究了Nd^(3+)掺杂量对S.Ndx物相组成、色度及Ba^(2+)-Nd^(3+)共掺杂对于S.Ndx抗氧化性能的影响,并运用FE-SEM、EDS、XRD、HR-TEM、UV-vis、CIELAB比色法以及TG-DSC等测试手段对S.Ndx进行表征分析。研究结果表明,当x在0 mol-0.10 mol范围内变化时,在850℃下便可以得到纯γ相的S.Ndx。随着Nd^(3+)含量的增加,S.Ndx的禁带宽度从2.06 eV增加到2.14 eV,使色料颜色从红色变成橙红色,其色度值从L^(*)=32.95、a^(*)=30.39、b^(*)=24.34(S.Nd0.00)增加到L^(*)=34.89、a^(*)=37.91、b^(*)=38.19(S.Nd0.05),随后有所降低,这表明Ba^(2+)-Nd^(3+)共掺杂可以有效地提高色料的色度值,将S.Nd0.05样品在440℃的空气气氛中保温10min,处理后仍显示纯γ相,并表现出较好的色度(L^(*)=22.31、a^(*)=23.87、b^(*)=27.62),这表明Ba^(2+)-Nd^(3+)共掺杂可有效提高γ-[Ba,Nd]-Ce_(2)S_(3)的抗氧化性能。

碱金属添加剂Na^+对γ-Ce_2S_3红色颜料合成及颜色的影响研究

γ-Ce2S3作为无机红色颜料,它的使用范围越来越广泛,其使用的要求是满足无毒性以及耐温、耐气候以及耐腐蚀性。本文主要通过两段法制备γ-Ce2S3的实验研究,将其结果进行比较,在原料中添加适量的碱金属Na+这样能够促使β-Ce2S3最终降低到γ-Ce2S3温度的变化。最终使得γ-Ce2S3在较低温度下的纯相,使其生成的物质中含有一定的钠离子,这样就改变了颜料的色调。颜料从红色向橘红色转变。但是最终提高了γ-Ce2S3的稳定性。

Influence of Ga^(3+) on Photoluminescence of Ce^(3+)

The electro optical characteristics of SrS∶Ce and SrGa 2S 4∶Ce as two kinds of hopeful blue TFEL phosphors have been intensively investigated. The color purity of SrGa 2S 4∶Ce is better than that of SrS∶Ce. In this paper, the influence of Ga 3+ on photoluminescence (PL) characteristics of Ce 3+ is first reported. Ga 2S 3 was doped into SrS, then sintered. The emission spectra shift obviously towards short wavelength range with increase of Ga 3+ concentration. At the same time, the relative intensity of the excitation peaks corresponding to the interband absorption of SrS reduces, and the excitation efficiency corresponding to the transition from the ground state to the excited state of Ce 3+ ion increases. The ligand field around Ce 3+ is changed by doped Ga 3+ . The ionicity of the substituted become stronger and Ce 3+ -Ce 3+ interaction become weaker. These are favorite to blue emission.

Preparation of SiO_2 coated Ce_2S_3 red pigment with improved thermal stability

SiO2 coated Ce2S3 red pigment was prepared in ethanol/H2O system via sol-gel method and TEOS were used as silica sources. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDX）, UV-visible spectro-photometer and automatic colorimeter were used to investigate the properties of the samples. The results showed that the compact SiO2 film formed on the surface of Ce2S3 pigment at a cerium silicon molar ratio of 2. The thermal stability temperature of Ce2S3 pigment was improved to 450 oC after SiO2 coating. In addition, the color of Ce2S3 pigment was not affected significantly through coating colorless and transparent SiO2 and it could be used as safe red pigment in higher temperature fields.

Effects of the precursor size on the morphologies and properties of γ-Ce_2S_3 as a pigment

Ceria spheres with different sizes and sulfurized products with corresponding morphology were prepared by hydro-thermal and gas-solid reaction method at 600-800℃ under CS2 atmosphere for a short time, respectively. Dimensional effect in preparation ofγ-Ce2S3 was firstly investigated by means of techniques such as scanning electron microscopy （SEM）, X-ray dif-fraction （XRD）, thermal gravimetric analysis （TGA） and spectrophotometer. The results showed that when ceria nanoparticles with small size were used as precursors, theγ-Ce2S3 could be prepared at the lower temperature and the badly sintered products were obtained; when ceria nanoparticles with large size were employed as precursors, pureγ-Ce2S3 was difficultly obtained even if the temperature was up to 800℃ and the products tended to keep their original size. The heat-resistance property of theγ-Ce2S3 with large size was better than the smaller one, and the pureγ-Ce2S3 prepared from precursor with small size had a good pigmen-tary performance.

Preparation of ternary rare earth sulfide La_xCe_(2-x)S_3 as red pigment

In order to investigate the suitability of ternary rare earth sulfide LanCe2 xS3 in plastic application as a red pigment, we prepared LaxCe2 xS3 via the sulfurization of the oxide powders using CS2 gas. In the sulfurization of LaxCe2_xS3, β-phase and y-phase ter- nary rare earth sulfide LaxCe2_xS3 were synthesized at the sulfufization temperature of 1000 and 1250 ℃ for 3 h, respectively. The UV-vis absorption spectra of synthesized LaxCe2_xS3 showed that the absorption wavelengths of 13-phase and y-phase LaxCe2_xS3 samies were in the region of 617-70 nm and 607-53 nm, respectively. They were in red absorption region. Furthermore, the scanning electron microscopy （SEM） results of the synthesized LaxCe2-S3 samples were investigated. The typical SEM microgmphs indicated that the particle sizes of synthesized LaxCe2 xS3 were in the range of 0.5-5 μm.

镨钕掺杂对γ-Ce_2S_3红颜料性能的影响

以镨钕氧化物富集物和无水碳酸钠作为添加剂掺杂到氧化铈中制得的混合物为原料,在1000℃经硫化氢气体硫化合成了一种新颖的γ型五元稀土倍半硫化物γ-Na-Ce-Pr-Nd-S红色环保颜料。使用X射线粉末衍射、固体可见漫反射光谱、热重-差示扫描量热分析及扫描电镜表征等测试手段对产物进行了表征。与未掺杂镨钕的产品对比,发现适量掺杂镨钕可降低硫化产物的烧结程度、增加产品亮度及增强产品的热稳定性。

Ca2+掺杂对γ-Ce2S3红色色料的结构及性能的影响

以CeO2为铈源, CaCO3为离子掺杂源, CS2为硫源,采用气-固相反应法,在硫化制度900℃硫化150 min时制得Ca2+离子掺杂的γ-Ce2S3红色色料。系统研究了不同的Ca, Ce摩尔比(nCa/nCe=0~0.5)对γ-Ce2S3的物相组成、晶体结构、呈色性能及温度稳定性的影响。研究结果表明:当未掺入Ca2+时,所得样品为纯α相,当nCa/nCe=0.1时,为α相与γ相共存;而当nCa/nCe=0.2~0.5时,α相已完全转变为γ相,并产生少量的CaS,且随着掺杂量的增大,γ-Ce2S3的晶胞参数逐渐减小,产生的CaS含量则略有增加,说明部分Ca2+成功进入晶格并形成固溶体,另有少量Ca2+则与S2-结合形成CaS;随着nCa/nCe增加,所合成样品的色调逐渐由暗红色向红色再向橙红色转变,且当nCa/nCe=0.4时,样品的红度值a*达到最高(L*=31.75,a*=24.50,b*=16.01)。将该组分色料在空气气氛中490℃保温10 min后仍以γ相稳定存在,表明通过Ca2+离子的掺杂,填补γ-Ce2S3晶格空位并形成固溶体,有利于稳定其晶格,从而使γ-Ce2S3的温度稳定性由350℃提升至490℃。