共沉淀法制备硅酸锆包裹炭黑及其高温稳定性

以正硅酸乙酯和氧氯化锆为原料, 采用溶胶共沉淀法制备了硅酸锆包裹炭黑复合粉体。利用XRD、SEM、色度计和粒度分析仪等手段对样品进行了表征。采用正交试验考察了前驱体pH值、煅烧温度、矿化剂种类和用量等工艺条件对复合粉体高温稳定性的影响。结果表明, 矿化剂和煅烧温度是最重要的影响因素。最佳的工艺条件是前驱溶液pH为5、矿化剂为5wt%LiF、煅烧温度为1150℃。该工艺条件下形成的球形镶嵌结构能够有效防止炭黑被氧化。获得的硅酸锆包裹炭黑粉体具有较好的高温稳定性, 粒度分布符合陶瓷色料的要求。该粉体用于熔块釉中, 1000℃烧成仍然具有较好的发色效果。     

Pr-ZrSiO4颜料（镨锆黄）的两步法合成与表征

以ZrOCl2.8H2O、Na2SiO3.9H2O及Pr6O11为原料,采用水热合成加高温热处理两步法制备得到纳米级镨锆黄颜料.用XRD、TEM、SEM、反射光谱、L*a*b*参数等测试方法表征了样品晶体结构、形貌、颜色以及反射光谱参数.研究结果表明:水热体系溶液的pH值、水热温度、热处理温度是影响产物晶体结构及颜料性能的主要因素.综合考虑颜料的晶型、光谱差值、粒径大小、均匀性以及分散性,当反应条件为水热温度220℃,水热体系溶液的pH值为3.5,热处理温度为900℃条件下所得样品的颜料性能较佳.     

矿化剂对磷酸锆基高温红色色料性能的影响

本文采用固相法以(NH_4)_2HPO_4、ZrO_2为原料,Ni_2O_3为着色剂,制备磷酸锆基高温红色色料,研究了六种不同单一矿化剂对陶瓷色料的呈色性能的影响,以及矿化剂ZnO的添加量对磷酸锆基高温红色色料性能的影响。通过XRD和紫外线可见光分光光度法对色料进行物相和色度分析。实验结果表明:在磷酸锆基高温红色色料中矿化剂的添加有利于色料的颜色更红更鲜艳,六种矿化剂的作用效果为ZnOKNO_3NaClH_3BO_3NH_4ClCaCl_2。当ZnO含量为0~1%时,由于Zr_2O(PO_4)_2少量的合成,色料的红色更亮,更鲜艳;继续增加ZnO含量(大于1%)时,ZnO的加入会使晶格活化,促进晶体Zr_2O(PO_4)_2的合成,致使主晶相由Ni_(0.5)Zr_2(PO_4)_3转变为Zr_2O(PO_4)_2,过多的Zr_2O(PO_4)_2导致色料吸收光的波长范围发生偏移,从而导致色料的颜色从红色变成黄色。     

煅烧条件对共沉淀法合成ZnZr_4(PO_4)_6粉体影响的研究

采用共沉淀法制备了磷酸锆锌(α-ZnZr_4(PO_4))粉体,探讨了磷酸锆锌粉体合成机理,研究了煅烧温度、保温时间等煅烧条件对粉体合成的影响,并用TG-DTA、FT-IR、XRD、TEM等方法进行表征。实验表明前驱体在900～950℃煅烧2h可以获得平均粒径200nm、结晶完全的α-ZnZr4(PO4)6粉体,采用此粉体制备的陶瓷材料1200℃时热膨胀系数为-2.0×10-6℃-1。     

钴-钛系列随角异色功能颜料的制备及性能研究

采用具有干涉色的云母钛作为基质材料,通过湿化学法制备随角异色功能颜料.用XRD、多角度色度仪、X-Rite MA-86Ⅱ5角度分光光度仪对颜料进行分析表征.考察实验条件对颜料随角异色效果的影响,分析了角度变化对颜料明度和颜色变化趋势的影响.结果表明,在具有干涉色的云母钛表面包覆氧化钴膜,能够制得变色效果较好的随角异色颜料,制备此种颜料的最佳反应条件是:反应温度70～80℃,pH9.5～10.5之间,加料速度2～3滴/min,煅烧温度900℃,煅烧时间60min,改变云母钛的干涉色可以制得多种颜色的随角异色颜料,随着观察角度的增加,颜料的明度增加,颜料呈现3种颜色变化.     

水热合成温度与保温时间对纳米COAl2O4色料性能的影响

以CoCl2·6H2O和AlCl3为原料,NaOH为沉淀剂,采用水热法合成尖品石型纳米钻蓝色料.主要研究合成温度和保温时间对CoAl2O4色料主晶相、呈色的影响,采用XRD,TEM,FTIR,TG-DTA分光光度计等分析测试技术对合成产物进行表征.结果表明,在245℃/20h能制备出纯度较高的纳米CoAl2O4,其晶型完整、粒度均匀,粒径多为70nm左右,此时的色饱和度和色度值也达最佳.     

水热法合成PZT粉体的研究

以硝酸铅、氧氯化锆、钛酸四丁酯为反应物前躯体,氢氧化钾为矿化剂,采用水热法合成PZT粉体.系统研究了反应温度、反应时间、矿化剂浓度和引入表面活性剂聚乙烯醇(PVA)对PZT晶体生长的影响.通过XRD和SEM对粉体进行了表征,探索出制备PZT粉体的最佳条件,研究结果表明:在KOH浓度为2 mol/L、180℃反应12 h的条件下可制备得到粒径约为1μm,粒径均匀,晶体发育完整的钙钛矿结构的PZT粉体;在该反应体系中加入适量PVA时得到了棒状纤维结构的粉体.     

微乳液法制备超细Co-Cr-Fe-Ni钴黑陶瓷颜料

利用AEO7(脂肪醇聚氧乙烯(7)醚)/环己烷/正丁醇体系,以微乳液法制备超细钴黑陶瓷颜料。绘制了不同温度下AEO7/环己烷/正丁醇/水的拟三元相图;运用马尔文粒度分布仪测定了不同前驱离子浓度制备的钴黑颜料粒径;通过XRD和FT-IR测定了钴黑颜料物相及结构,采用UV-Vis和色差仪对钴黑颜料呈色进行分析。结果表明,该微乳液体系制备的钴黑颜料颗粒度随着前驱离子浓度降低而减小,粒度分布窄且均匀;钴黑颜料是系列尖晶石型物质;随着煅烧温度升高,钴黑颜料呈现较纯正黑色,偏红现象降低。     

三乙醇胺-水溶液介质水热合成纳米四方相氧化锆粉体

以氨水为沉淀剂,将其缓慢滴加至氧氯化锆和硝酸钇混合溶液制备氧化锆前驱体;以有机溶剂三乙醇胺为矿化剂,水热晶化制备纳米四方相氧化锆。着重研究了水热温度、时间、矿化剂浓度对粉体结晶性能、分散性、粒径、形貌的影响,通过XRD、TEM对粉体进行表征。结果表明,通过选择适当的条件,可制得分散性良好、粒径分布窄的四方相纳米氧化锆;有机矿化剂的加入和水热温度的升高有助于提高粉体的结晶度和分散性能。     

纳米立方LiF的液相制备及表征

以NH₄F和LiOH·H₂O为原料、无水乙醇为溶剂和结晶控制剂,采用液相法合成前驱体低温烧结制备纳米级LiF粉末。利用X射线粉末衍射、扫描电镜、透射电镜和激光粒度仪等分析手段对样品进行表征。结果表明,前驱体的主要成分为LiF、NH₄F和LiOH·H₂O;热分析结果表明,NH₄F的分解温度约为190℃。在220~400℃烧结后得到的样品具有单一的LiF立方晶体结构,颗粒饱满,大小均匀,形貌良好,粒径的平均尺寸为80 nm。     

Effect of ferrous/ferric ions molar ratio on reaction mechanism for hydrothermal synthesis of magnetite nanoparticles

Magnetite nanoparticles were prepared by hydrothermal synthesis under various initial ferrous/ferric molar ratios without adding any oxidizing and reducing agents in order to clarify effects of the molar ratio on the reaction mechanism for the formation of magnetite nanoparticles. The magnetite nanoparticles prepared were characterized by a scanning electron microscope, powder X-ray diffractometer, and superconducting quantum interference device (SQUID). At the molar ratio corresponding to the stoichiometric ratio in the synthesis reaction of magnetite from ferrous hydroxide and goethite, the nucleation of magnetite crystals progressed rapidly in an initial stage of the hydrothermal synthesis, resulting in formation of the magnetite nanoparticles having a smaller size and a lower crystallinity. On the other hand, at higher molar ratios, the particle size and crystallinity increased with increasing molar ratio because using surplus ferrous hydroxide the crystallites of magnetite nanoparticles grew up slowly under hydrothermal conditions according to the Schikorr reaction. The magnetite nanoparticles prepared under various molar ratios had good magnetic properties regardless of the molar ratio.     

添加La2O3对粉煤灰合成Al2O3-SiC复合粉体的影响

以粉煤灰和活性炭为原料,通过碳热还原反应在Ar气氛下合成Al_2O_3-SiC粉体,探究了一条低成本合成Al_2O_3-SiC粉体的可行途径。研究了添加La_2O_3对合成过程的影响。采用XRD和SEM表征了材料的物相组成和显微形貌。结果表明:当粉煤灰与活性炭质量比为100∶44,在1 550℃下保温5h,添加6%(质量分数)的La_2O_3时,可合成性能良好的Al_2O_3-SiC粉体,颗粒分布均匀,平均粒径为0.5~1μm,较不添加La_2O_3合成温度降低约50℃。     

溶胶凝胶法制备磷酸锆钠陶瓷材料

以Zr(NO3)4.5H2O、NH4H2PO4和NaNO3为原材料,采用溶胶凝胶法合成了磷酸锆钠(NaZr2(PO4)3)陶瓷粉体,采用TG-DTA,XRD和SEM测试方法对粉体性能进行了表征,研究了烧结温度和pH值等反应条件对粉体合成的影响.结果表明,要获纯的磷酸锆钠粉体,合成温度需控制在800～1 000℃之间,其中最合适合成温度为900℃左右.前驱体pH值对合成温度基本没有影响,但会影响产物微观形貌.当合成温度为900℃,pH值为9时可以制备出团聚较少、颗粒均匀、分散性较好且平均粒径为100nm的磷酸锆钠粉体.     

Molten-salt assisted synthesis and characterization of ZrSiO4 coated carbon core-shell structure pigment

A core-shell structure zirconium silicate encapsulated carbon (C@ZrSiO₄) pigment was synthesized by a molten-salt assisted method. The experimental results indicated that the Na₂WO₄ molten-salt associated with the synthesis of ZrSiO₄ at low temperature and controlled the morphology of the encapsulation pigment simultaneously. The encapsulated pigment prepared with the assistance of Na₂WO₄ molten-salt showed regular microcubes about 3.0 μm, while the pigment in the absence of molten-salt have serious aggregation with a particle size of 12.78 μm. Moreover, the maximum addition amount of carbon black was increased significantly from 15 wt% to 40 wt% after adding molten-salt, while the chromatic value L* of C@ZrSiO₄ pigment decreased from 68.21 to 33.08 accordingly. The pigment exhibited excellent thermal stability at high temperature, making it a promising candidate for ceramic decoration.     

Effect of the milling method and particle structure on the color tone of (Cr,Fe)2O3 inorganic black masterbatch pigment

(Cr, Fe)₂O₃ pigment was milled using different techniques into the same particle sizes to investigate the influence of milling processes on its properties. The research showed that milling type resulted in significant color differences, accompanied by the pigment color changing from intense reddish-brown to dark brown. Differences in the morphology of the particles embedded in the plastic matrix led to different light scattering, which is observed as a decrease in the color saturation of the pigment. Particle size distribution (PSD) was characterized by measuring with a laser diffraction particle size analyzer. Pigments were milled down to 4 µm in all milling methods. The very small particles in the pigment affected the light scattering and the color tone. The particle size of the pigment milled by the planetary mill was D₁₀ = 0.035 μ ± 0.1. Color values of the plastic plates were measured according to CIE laboratory analysis. The pigment milled with the planetary mill was lighter, greener, and yellower (ΔL*=4.15, Da*=3.68, Db*=2.96). The pigment milled with the jet-mill was closest to the pigment color after calcination. The pigment milled with ball mill was slightly greener than the values after calcination (Da*=1).     

纳米钴蓝共沉淀法制备技术

以硝酸钴、硝酸铝为原料,NaOH或尿素为沉淀剂,采用共沉淀法制备纳米钴蓝。考察了Co/Al摩尔比、沉淀剂种类和煅烧温度等因素对纳米钻蓝呈色性能影响,采用包括可见光分度计等多种方法表征了纳米钴蓝的结构及形貌特征及纳米钴蓝色度值。研究结果表明:(1)煅烧温度为1000℃时,当Co/Al摩尔比从1∶3升至1∶1,钴蓝颜色从蓝色依次向蓝绿色、暗绿色转变,同时,以NaOH为沉淀剂制备的钴蓝其亮度比以尿素为沉淀剂制备的钴蓝高;(2)以NaOH为沉淀剂,Co/Al摩尔比为1∶3时,当煅烧温度为900℃,钴蓝呈蓝绿色,当煅烧温度为1000-1100℃,钴蓝呈蓝色;(3)钴蓝不同制备工艺会改变钴d电子层状态,导致钴蓝呈现不同颜色,最终优化工艺制备的纳米钴蓝粒径为45-65nm,呈尖晶石型晶体结构,色度值为CIE(35.86,-12.63,-34.83)。     

Hydrothermal synthesis of magnetite nanoparticles via sequential formation of iron hydroxide precipitates

A novel method for preparing fine magnetite nanoparticles without using any additives and organic solvents has been developed. In this method, a sequential precipitates formation method, ferrous and ferric hydroxides are not coprecipitated but sequentially formed in an alkaline solution, and then the resulting suspension is subjected to a hydrothermal treatment. The obtained magnetite nanoparticles were characterised through scanning electron microscopy observation and X-ray diffraction analysis, and the particle size and magnetic properties were measured with a dynamic light scattering particle size analyser and a superconducting quantum interference device magnetometer, respectively. In order to prepare fine magnetite nanoparticles with a uniform size, both the formation sequence of ferrous and ferric hydroxide precipitates and the supersaturation of ferric hydroxide in the solution were essential. The ferromagnetic magnetite nanoparticles with a median size 8.5?nm were relatively easily obtained in the formation process in which a ferric sulphate solution was rapidly poured into a suspension of ferrous hydroxide particles prepared beforehand using ferric chloride and sodium hydroxide, whereas the median size of magnetite nanoparticles prepared via conventional coprecipitation route was 38.6?nm.     

高通量合成方法制备球霞石相CaCO3材料及表征

高通量合成CaCO_3方法为该材料的工业生产提供一定的理论基础,其目的是为了获得粒度分布均匀、比表面积高、球霞石相含量高的花蕊状CaCO_3.利用高通量合成材料的优势,设计并构建了自动加注试剂、独立控温及控速的高通量自动合成装置,并进行了合成CaCO_3的工作.以氯化钙、碳酸钠、咖啡酸为原料,在同一时间内完成不同实验条件下CaCO_3的合成,采用X射线衍射(XRD)、扫描电镜(SEM)、激光粒度仪,对样品的结构、形貌、粒径分布进行表征和分析,并利用高通量合成实验方法进行CaCO_3合成优化实验.结果表明:在水和乙醇分别作为溶剂时,合成球霞石相(晶形)CaCO_3的含量不同.即咖啡酸浓度20 mg/mL(乙醇为溶剂,10 mL)、CaCl_2与Na_2CO_3的物质的量之比为3∶1时,合成粒度分布均匀、花蕊状、球霞石相(晶形)含量高达98.31%、比表面积为51.9 m~2/g的CaCO_3材料.与传统合成实验方法相比,高通量合成将会缩短研发及合成时间.