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1、,粉体制备 成型 烧结,关键: 高纯、超细、组分均匀分布和无团聚的粉体,机械制粉 化学制粉,纳米材料是纳米科技的基础，而纳米粒子的制备及其表征工作是纳米材料研究领域中的最基本、最重要的研究工作。目前，纳米粒子的制备方法很多，根据不同的分类标准，可以有多种分类方法。根据反应环境可分为液相法、气相法和固相法；根据反应性质可分为化学制备法、化学物理制备法和物理制备法。不同的制备方法可导致纳米粒子的性能以及粒径各不相同。,1化学沉淀法,特点：简单易行，但纯度低，颗粒半径大。 适合制备氧化物。 （1）共沉淀法 （2）均相沉淀法,（1）共沉淀法 通过化学反应将溶液中的金属离子共 沉下来。先将金属盐类按比例
2、配好，在溶液 均匀混合，再用强碱作沉淀剂，将多种金属离子共同沉淀下来。,Fabrication and Characterization of BaCO3 Nanostructures,BaCO3 Ba2+ + CO32-,思路：,BaCl2 Ba(NO3)2 Ba(CH3COO)2,Na2CO3 NaHCO3 (NH4)2CO3,BaCO3纳米结构的制备及表征,In a typical experiment, barium nitrate (Ba(NO3)2) (0.261 g) and ammonium carbonate (NH4)2CO3)(0.096 g) or sodium car
3、bonate (Na2CO3) (0.106 g) or sodium bicarbonate (NaHCO3) (0.084 g) were dissolved in deionized water (20 mL) in a flask under magnetic stirring for 30 min at room temperature. The product was separated from the solution by centrifugation, washed with absolute ethanol and dried in vacuum.,TEM microgr
4、aphs of the samples prepared using NaHCO3 as the CO32 source for different time:(a-c) 30 min; (a) A typical TEM micrograph; (b) an individual nanorod and the corresponding SAED pattern of the individual nanorod before and after exposure to electron beam irradiation, respectively;(c) the rod assemble
5、d from nanoparticlesand the corresponding SAED pattern. (d-h) 30 s.,TEM micrographs of the sample prepared using Na2CO3 as the CO32 source. (a) A typical TEM micrograph; (b) an individual nanorod and the corresponding SAED pattern. (c) the rod and the corresponding SAED pattern taken after exposure
6、to electron beam irradiation.,SEM micrographs of the sample prepared using (NH4)2CO3 as the CO32 source. (a) A typical SEM micrograph; (b) an individual flower-like structure.,Synthesis of Needle-like and Flower-like Zinc Oxide by a Simple Surfactant-free Solution Method,思路：,ZnCl2 Zn(NO3)2 Zn(CH3COO
7、)2,NaOH 尿素 六次甲基四胺,一种简单液相法制备针状和花状氧化锌,n2+OH-,温度,In a typical experimental procedure,Zn(CH3COO)22H2O or Zn(NO3)26H2O was dissolved in deionized water to form 0.13M solution. Excess NaOH was dissolved in the above solution at room temperatureby a magnetic stirrer (NaOH = 1.3 M). A white precipitate occu
8、rred immediately but it was dissolved by further stirring. The above solution was heated by an oil bath at appropriate temperature for a certain time. Then the heating was terminated and the solution was allowed to cool to room temperature. The products were separated by centrifugation, washed with
9、absolute ethanol three times, and dried at 60C in a vacuum. White powders were obtained.,a) Sample 1 and b)Sample 2*Zn(OH)2;ZnO Samples 1 and 2 were prepared at 50 and 90C for 30 min in an oil bath, respectively. Zn(NO3)26H2O was used as the zinc source;,c) Sample 3 prepared at 90C for 30 min. Zn(CH
10、3COO)22H2O was used as the zinc source; d) Sample 4 prepared at 120 C for 30 min. Zn(NO3)2.6H2O was used as the zinc source;,e) Sample 5 and f) Sample 6. Samples 5 and 6 were prepared at 50 and 90C for 90 min, respectively.Zn(NO3)26H2O was used as the zinc source;,TEM micrographs of two as-prepared
11、ZnO samples. a)c) Sample 7 prepared at 90C for 90 min in an oil bath. Zn(CH3COO)22H2O was used as the zinc source;,d)f) Sample6 prepared at 90 C for 90 min. Zn(NO3)26H2O was used as thezinc source.,（）均相沉淀法 一般的沉淀过程是不平衡的，但如果控制溶 液中的沉淀剂浓度，使之缓慢地增加，则使溶液 中的沉淀处于平衡状态，且沉淀能在整个溶液中 均匀地出现，这种方法称为均相沉淀。 通常通过溶液中的化学反应
12、使沉淀剂慢慢生 成，克服由外部向溶液中加沉淀剂而造成沉淀剂的 局部不均匀性，造成沉淀不能在整个溶液中均匀出 现的缺点。 例如，随尿素水溶液的温度逐渐升高至70附 近，尿素会发生分解，即 (NH2)2CO + 3H2O 2NH4OH + CO2,生成的沉淀剂NH4OH在金属盐的溶液中分布均匀，浓度低，使得沉淀物均匀地生成。 由于尿素的分解速度受加热温度和尿素浓度的影响，可以控制这两种因素使尿素分解生成NH4OH的速度降得很低。 有人用低的尿素分解速度来制得单晶微粒，用此种方法可制备多种盐的均匀沉淀，如锆盐颗粒以及球形A1(OH)3粒子。,用电子分析天平准确称量0.8302g十二水合硫酸铝钾以及0
13、.2102g尿素，加入盛有35mL蒸馏水的烧杯中，在磁力搅拌器上搅拌使其完全溶解，然后倒入反应釜中，180oC加热反应3个小时，然后自然冷却至室温，分别用蒸馏水洗涤3次，再用无水乙醇洗涤1次，最后在60oC烘箱中干燥。,羟基氧化铝的制备过程,羟基氧化铝的XRD图谱,以氯化铝为铝源,以硫酸钾铝为铝源,化学还原法,（1）水溶液还原法 采用水合肼、葡萄糖、硼氢化钠(钾)等还原剂， 在水溶液中制备超细金属粉末或非晶合金粉末，并利 用高分子保护剂PVP (聚乙烯基吡咯烷酮)阻止颗粒团 聚及减小晶粒尺寸。其优点是获得的粒子分散性好， 颗粒形状基本呈球形，过程可控制。,实例：氧化亚铜的制备(Cu2O),思路
14、：,Cu2+还原剂+OH- Cu2O,水合肼、葡萄糖、硼氢化钠(钾) 抗坏血酸、亚硫酸钠、乙醛等,Sample 1 was prepared by following process: 0.05 g d- glucose was dissolved in 50 mL 0.01 M CuCl2 aqueous solution, and 5 mL 0.1 M NaOH aqueous solution was added under magnetic stirring. The solution was heated to 95 C by oil bath. Then, 10 mL 0.1 M
15、NaOH aqueous solution was added dropwise and kept at 95 C for 5 min. After the mixture was cooled to room temperature, the product was separated by centrifugation and washed with deionized water three times and dried at 60C in vacuum.,（2）多元醇还原法 该工艺主要利用金属盐可溶于或悬浮于乙二醇(EG)、一缩二乙二醇(DEG)等醇中，当加热到醇的沸点时，与多元醇发
16、生还原反应，生成金属沉淀物，通过控制反应温度或引入外界成核剂，可得到纳米级粒子。,In a typical experiment, 0.443 g SeO2 and 40 ml EG were mixed and placed in a 100ml round-bottomed flask and heated to 195 C and kept at this temperature for 30 min by microwave heating. The black suspension solutions were obtained after microwave heating. The products were separated from solutions by centrifugation, washed by ethanol several times and dried at 80 C in vacuum. Finally, black powders were obtained.,注意：EGethylene glycol,（3）气相还原法
