机械力化学法制备钛酸钡粉体

采用等摩尔比的BaCO_3和TiO_2粉体作为前驱物,利用高能球磨法球磨10h,XRD结果表明在球磨过程中,粉体颗粒大大细化,将球磨后的混合物在较低的温度下(<900℃)煅烧即可合成纯相的立方BaTiO_3粉体,当温度提高到1100℃,合成了四方相BaTiO_3粉体,在>1100℃煅烧时,晶粒尺寸急剧增大。     

机械力化学在纳米无机材料制备中的应用

通过高能球磨实现的超细粉碎过程使固体颗粒晶粒细化,产生微裂纹、晶格畸变、表面能升高、反应能力增强,从而实现低温化学反应,称为机械力化学.此法开辟了制备材料的新途径,因而得到广泛重视.本文综述了机械力化学原理及其在制备纳米复合材料、纳米陶瓷材料和纳米合金材料中的应用以及工艺控制因素.介绍了机械力化学法的发展现状及其优缺点.     

溶胶-凝胶法制备钛酸锶粉体及其光催化性能的研究

用溶胶-凝胶法制备钙钛矿型SrTiO₃粉体。并用自制的反应器,考察了SrTiO₃粉体对NOx的光催化脱除能力,研究了光源、气体初始浓度、湿度对光催化效果的影响。结果表明,经过45 min的光催化反应,不同浓度的气体中NOx的脱除率均在70%以上。     

流变相-前驱物法制备纳米氧化镁粉体

以普通氧化镁和邻苯二甲酸为原料,采用流变相-前驱物法制备了纳米氧化镁粉体,用元素分析和红外光谱表征了前驱物的组成和结构,通过热重分析确定了煅烧温度,分别用X射线粉末衍射、透射电镜对纳米氧化镁粉体的结构及形貌大小进行表征。用该法制备出的纳米氧化镁粉体为立方晶型,形状近似球形,分散性好,平均粒径约为10 nm。     

超重力反应沉淀法制备白炭黑的研究

利用超重力反应沉淀法，以水玻璃和二氧化碳为原料，制备了平均一次粒径为15－20nm的白炭黑粉体，研究了反应条件对产品粒径的影响，通过透射电镜（TEM），红外（IR），X射线衍射（XRD）和差热一热重分析（DTA－TG）等手段检测了产品的性能，通过超重力反应沉淀法制备的白炭黑粉体，具有颗粒较细，粒度分布窄的特点，而超重力的制备方法也具有易于工业化的明显优点。     

超细氧化铬制备方法的研究进展

介绍了超细氧化铬粉体的用途、制备方法，着重介绍了超细氧化铬粉体近年来新的制备方法(包括微乳液法，溶胶-凝胶法，气体冷凝法，微波等离子法，激光诱导热解法，超临界流体脱溶法，机械化学法)及研究进展。分析了各种方法的利弊，以及以后的研究方向。     

Hydrogen evolution performance of magnesium alanate prepared by a mechanochemical metathesis reaction method

Solvent-free magnesium alanates were prepared by a mechanochemical metathesis reaction method (ball milling method) with a variation of milling time. For the purpose of comparison, magnesium alanate was also prepared by metathesis reaction method in the presence of diethyl ether. The formation of magnesium alanate (Mg(AlH₄)₂) and magnesium alanate-diethyl ether (Mg(AlH₄)₂·Et₂O) adduct was confirmed by XRD measurements. In both magnesium alanates, hydrogen evolution occurred in the first step decomposition. The starting temperature for hydrogen evolution of the solvent-free magnesium alanates decreased with increasing milling time, whereas the amount of hydrogen evolution of the solvent-free magnesium alanates increased with increasing milling time. The maximum amount of hydrogen evolution of the Mg(AlH₄)₂·Et₂O adduct was slightly larger than that of the solvent-free Mg(AlH₄)₂, but the starting temperature for hydrogen evolution of the Mg(AlH₄)₂·Et₂O adduct was much higher than that of the solvent-free Mg(AlH₄)₂. The addition of a small amount of titanium to the solvent-free Mg(AlH₄)₂ greatly reduced the hydrogen evolution temperature of titanium-doped Mg(AlH₄)₂. However, the maximum amount of hydrogen evolution of the titanium-doped Mg(AlH₄)₂ was smaller than that of the solvent-free Mg(AlH₄)₂.     

卤水石灰法制备Mg(OH)_2

为降低卤水石灰法制备Mg(OH)2过程中产物中的钙摩尔分数,探讨了卤水浓度、反应温度、卤水滴加速度、加料方式等对产品质量的影响规律,采用正交实验研究洗涤时间、洗涤温度、洗涤用水量和洗涤次数各因素对钙摩尔分数的影响效果.研究结果表明,卤水滴加速度为3 mL/min、卤水浓度控制为1.5 mol/L、反应温度在60℃时可以制得钙摩尔分数较低的Mg(OH)2,洗涤脱钙的影响效果的主次顺序基本为洗涤温度大于用水量大于洗涤时间大于洗涤次数.     

常压一步法合成纳米钛酸钡粉体

以廉价的四氯化钛、氯化钡和氢氧化钠为主要原料,采用常压一步法合成纳米钛酸钡粉体.研究了四氯化钛水解程度、pH、反应温度和添加表面活性剂等因素对制备的纳米钛酸钡粉体纯度和形貌的影响.结果表明:在最佳工艺条件下,通过该方法合成的纳米钛酸钡粉体为立方晶系,呈均匀球形,粒径分布在20 nm左右,纯度为99.85%,钡与钛物质的量比为1.000±0.005.与水热合成法相比,该法具有反应温度和压力低、无需焙烧等优点.     

反应沉淀法制备超细硫酸沙丁胺醇颗粒及其粉雾剂的表征

The preparation of ultra-fine particles of salbutamol sulphate （SS） was accomplished with a reactive precipitation pathway, in which salbutamol and sulphuric acid were Used as reactants with the solvents of ethanol.The effects of sulphuric acid concentration, reaction temperature, stirring rate, and reaction time onthesize of the particle were investigated. A binary mixture composed of lactose and SS was prepared to evaluate SS. The results showed that ultra-fine SS particles with controlled diameters ranging between 3 μm and 0.8 μm and with a narrow distribution could be achieved. The morphology consisting of clubbed particles wassuccess.fully obtained. The purity of the particles reached above 98% with-UV detection. The dose- of dry powder inhalation was obtained by blending the particles with recrystallized lactose, which acted as a carrier. The deposition quantity of the drug in breathing tract was estimated using a twin imPinger apparatus. Compared with the Shapuer powder （purchased in the market）, the results showed that SS_particles had more quantifies.subsided in simulative lung.. _     

Low-temperature synthesis of superfine barium strontium titanate powder by the citrate method

Ba_0.6Sr_0.4TiO₃ powder was synthesized by a citrate method. The phase development was examined with respect to calcining temperature and heating rate during the calcining process. The results reveal a crucial role of the heating rate to the formation of a pure perovskite phase at low calcining temperatures. It was found that keeping relatively low heating rates ≤0.7 °C/min during the calcining process after 300 °C was favorable to a sufficient decomposition of (Ba,Sr)₂Ti₂O₅·CO₃ intermediate phase at low temperatures and consequently led to the formation of a pure perovskite phase at 550 °C. Ba_0.6Sr_0.4TiO₃ powder calcined at the temperature under the heating rate of 0.7 °C/min showed a superfine and uniform particle morphology and high sintering reactivity. As a result, the ceramic specimens prepared from the powder attained reasonable relative densities (94–95%) at sintering temperatures of 1250–1270 °C.     

钛酸锶钡压电陶瓷超细粉体的水热法合成

采用水热工艺制备不同组成的BaxSr1-xTiO3(BST)，利用FT-IR，XRD，TEM等技术分析了水热反应转变机理及相结构转变情况，同时对影响合成的工艺参数以及不同组成材料的居里温度变化进行了研究。结果表明：获得的BST粉体颗粒粒度较细，粒径为20～40nm。其最佳的工艺参数为n(Ba)／n(Ti)=3，n(Sr)／n(Ti)=1／4或者n(Ba)／n(Ti)=1／3，n(Sr)／n(Ti)=4／5，cKOH=1．5～2mol／L。制得不同组成粉体的居里温度呈规律性变化。