《最后一份三四章结合的陶瓷粉体制备》由会员分享,可在线阅读,更多相关《最后一份三四章结合的陶瓷粉体制备(80页珍藏版)》请在金锄头文库上搜索。
1、结构陶瓷制备工艺结构陶瓷制备工艺粉体制备粉体制备成型成型烧结烧结关键: 高纯、超细、组分均匀分布和无团聚的粉体高纯、超细、组分均匀分布和无团聚的粉体机械制粉机械制粉化学制粉化学制粉 球磨和搅拌振动磨 液相法 固相法 气相法 粉体制备粉体制备 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。 液相法(S
2、olution-based method)制备纳米微粒是将均相溶液通过各种途径使溶质和溶剂分离,溶质形成一定形状和大小的颗粒,得到所需粉末的前驱体,热解后得到纳米微粒。液相法具有设备简单、原料容易获得、纯度高、均匀性好、化学组成控制准确等优点,主要用于氧化物系超微粉的制备。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 Nan
3、ostructuresBaCO3 Ba2+ + CO32-思路:BaCl2Ba(NO3)2Ba(CH3COO)2Na2CO3NaHCO3(NH4)2CO3BaCO3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 carbonate (Na2CO3) (0.106 g) or sodium bicarbonate (NaHCO3) (0.084 g) were dissolved in deioni
4、zed water (20 mL) in a flaskunder magnetic stirring for 30 min at roomtemperature. The product was separated from the solution by centrifugation, washed with absolute ethanol and dried in vacuum.TEM micrographs of the samples prepared using NaHCO3 as the CO32 source for different time:(a-c) 30 min;
5、(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 assembled from nanoparticlesand the corresponding SAED pattern. (d-h) 30 s.TEM micrographs of the sampl
6、e 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 afterexposure to electron beam irradiation.SEM micrographs of the sample prepared using (NH4)2CO3 as the CO32 so
7、urce.(a) A typical SEM micrograph; (b) an individual flower-like structure.Synthesis of Needle-like and Flower-like Zinc Oxideby a Simple Surfactant-free Solution Method思路:ZnCl2Zn(NO3)2Zn(CH3COO)2NaOH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一种简单液相法制备针状和花状氧化锌n2+OH-n(OH)2 ZnO+H2On(OH)42- ZnO+H2O+2OH-温度温度In a typical
8、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 occurred immediately but it was dissolved by further stirring.
9、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 absolute ethanol three times, and dried at 60C in a vacuum.
10、 White powders were obtained.a) Sample 1 and b)Sample 2*Zn(OH)2;ZnOSamples 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(CH3COO)22H2O was used as the zinc source; d) Sample 4 prepared
11、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 ZnO samples.a)c) Sample 7 prepared at 90C for 90 min in an oil
12、 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()均相沉淀法 一般的沉淀过程是不平衡的,但如果控制溶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,这种方法称为均匀地出现,这种方法称为均相沉淀均相沉
13、淀。通常通过溶液中的化学反应使沉淀剂慢慢生通常通过溶液中的化学反应使沉淀剂慢慢生成,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。现的缺点。例如,随尿素水溶液的温度逐渐升高至例如,随尿素水溶液的温度逐渐升高至7070附附近,尿素会发生分解,即近,尿素会发生分解,即 (NH(NH2 2) )2 2CO + 3HCO + 3H2 2O O 2NH 2NH4 4OH + COOH + CO2 2生生成成的的沉沉淀淀剂剂NHNH4 4OHOH在在金金属属盐盐的的溶溶液
14、液中中分分布布均均匀匀,浓度低,使得沉淀物均匀地生成。浓度低,使得沉淀物均匀地生成。由由于于尿尿素素的的分分解解速速度度受受加加热热温温度度和和尿尿素素浓浓度度的的影影响响,可可以以控控制制这这两两种种因因素素使使尿尿素素分分解解生生成成NHNH4 4OHOH的速度降得很低。的速度降得很低。有有人人用用低低的的尿尿素素分分解解速速度度来来制制得得单单晶晶微微粒粒,用用此此种种方方法法可可制制备备多多种种盐盐的的均均匀匀沉沉淀淀,如如锆锆盐盐颗颗粒以及球形粒以及球形A1(OH)A1(OH)3 3粒子粒子。 用电子分析天平准确称量0.8302g十二水合硫酸铝钾以及0.2102g尿素,加入盛有35m
15、L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 以氯化铝为铝源以氯化铝为铝源以硫酸钾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、硼氢化钠水合肼、葡萄糖、硼氢化钠( (钾钾) )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(Cu
16、2O)思路:Cu2+还原剂+OH- Cu2O水合肼、葡萄糖、硼氢化钠水合肼、葡萄糖、硼氢化钠( (钾钾) )抗坏血酸、亚硫酸钠、乙醛等抗坏血酸、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 b
17、y oil bath. Then, 10 mL 0.1 M 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
18、二乙二醇(DEG)等醇中,当加热到醇的沸点时,与多元醇发生还原反应,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
19、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)气相还原法本法也是制备微粉的常用方法。例如,用H2还原制备金属氧化物等。(4)碳热还原法碳热还原法的基本原理是以炭黑、SiO2为原料,在高温炉内氮气保护下,进行碳热还原反应获得微粉,通
20、过控制工艺条件可获得不同产物。目前研究较多的是Si3N4、SiC粉体及SiC-Si3N4复合粉体的制备。3 水热与溶剂热合成方法水热与溶剂热合成方法水水热热法法(Hydrothermal Synthesis),是是指指在在特特制制的的密密闭闭反反应应器器(高高压压釜釜)中中,采采用用水水溶溶液液作作为为反反应应体体系系,通通过过对对反反应应体体系系加加热热、加加压压(或或自自生生蒸蒸气气压压),创创造造一一个个相相对对高高温温、高高压压的的反反应应环环境境,使使得得通通常常难难溶溶或或不不溶溶的的物物质质溶溶解解,并并且且重重结结晶晶而而进进行行无无机合成与材料处理的一种有效方法。机合成与材料
21、处理的一种有效方法。 溶溶剂剂热热法法(Solvothermal Synthesis),将将水水热热法法中中的的水水换换成成有有机机溶溶剂剂或或非非水水溶溶媒媒(例例如如:有有机机胺胺、醇醇、氨氨、四四氯氯化化碳碳或或苯苯等等),采采用用类类似似于于水水热热法法的的原原理理,以以制制备备在在水水溶溶液液中中无无法法长长成成,易易氧氧化化、易水解或对水敏感的材料。易水解或对水敏感的材料。如如III-VIII-V族族半半导导体体化化合合物物、氮氮化化物物、硫硫族族化化合合物物、新型磷(砷)酸盐分子筛三维骨架结构等。新型磷(砷)酸盐分子筛三维骨架结构等。 水热与溶剂热合成的生产设备水热与溶剂热合成的
22、生产设备高压釜高压釜是进行高温高压水热与溶剂热合成的是进行高温高压水热与溶剂热合成的基本设备;基本设备;高高压压容容器器一一般般用用特特种种不不锈锈钢钢制制成成, ,釜釜内内衬衬有有化化学学惰惰性性材材料料,如如PtPt、AuAu等等贵贵金金属属和和聚聚四四氟氟乙乙烯烯等等耐耐酸酸碱碱材材料。料。简易高压反应釜实物图简易高压反应釜实物图带搅拌高压反应釜装置图带搅拌高压反应釜装置图水热与溶剂热合成的一般工艺是:水热与溶剂热合成存在的问题水热与溶剂热合成存在的问题l无法观察晶体生长和材料合成的过程,不直观。无法观察晶体生长和材料合成的过程,不直观。l设设备备要要求求高高耐耐高高温温高高压压的的钢钢
23、材材,耐耐腐腐蚀蚀的的内内衬衬、技术难度大温压控制严格、成本高。技术难度大温压控制严格、成本高。l安安全全性性差差,加加热热时时密密闭闭反反应应釜釜中中流流体体体体积积膨膨胀胀,能够产生极大的压强,存在极大的安全隐患。能够产生极大的压强,存在极大的安全隐患。In a typical procedure, 0.25 g cobalt acetate (Co(CH3COO)24H2O) was dissolved in 30 ml mixed solvents of deionized water and glycerol with a volume ratio of (3:1) at room
24、temperature, and then the solution was transferred into a Teflon-lined autoclave of 40 ml capacity, and maintained at 200 C for 10.5 h, followed by cooling to room temperature, this sample was denoted as sample 1. The product was then collected by centrifugation and washed with deionized water and a
25、bsolute ethanol repeatedly, then dried in air at 60 C. Co(OH)2纳米结构材料的表征纳米结构材料的表征10 m(c)10 m(b)1 m(d)(a)Co(OH)2纳米结构材料的表征纳米结构材料的表征水/丙三醇1/3Co(OH)2(b)10 m(c)1 m(a)(b)-100-110010水+乙二醇水+丙三醇+NaOHCo(OH)2纳米结构材料的表征纳米结构材料的表征(a)(b)-100-110010(c)010-110-100(d)-100010-202-1100-222-20(e)60 0.284 nm0.284 nmCo(OH)2纳
26、米结构材料的表征纳米结构材料的表征-Co(OH)2 -Co(OH)2和CoOOH CoOOH和Co3O4 照射时间逐渐延长-2020-222-20(d)(e)(c)1 m(b)10 m(a)1 m0.284 nm60 0.284 nmCo(OH)2纳米结构材料热分解转化为纳米结构材料热分解转化为Co3O4作 业1、什么是化学共沉淀法?2、什么是均相沉淀法?3、什么是水热法?溶剂热法? 微乳液法 概念 组成 表面活性剂组成及分类 临界胶束浓度 微乳液法的特点 应用实例 两种互不相溶互不相溶的溶剂在表面活性剂表面活性剂的作用下形成乳液,在“微泡微泡”中经成核、聚结、团聚、热处理后得到纳米粒子。 微
27、乳液微乳液是热力学稳定、透明的水滴在油中(WO)或油滴在水中(OW )形成的单分散体系,是表面活性剂分子在油水界面形成的有序组合体。 微乳液概念1943年Schulman等在乳状液中滴加醇,首次制得了透明或半透明、均匀并长期稳定的微乳液。1982年Boutnonet等 首先在WO型微乳液的水核中制备出Pt,Pd,Rh等金属团簇微粒,开拓了一种新的纳米材料的制备方法。 水滴在油中(WO)反相胶束油滴在水中(OW ) 胶束型微乳液 表面活性剂 水 油 微乳液通常是由表面活性剂表面活性剂、助表面活性剂助表面活性剂( (通常为通常为醇类醇类) )、油类油类( (通常为碳氢化合物通常为碳氢化合物) )和
28、和水水组成的透明、各向同性的热力学稳定体系。微乳液组成常用的油常用的油- -水体系有水体系有: :常用的表面活性剂有常用的表面活性剂有: :例如:正己烷-水,环己烷-水等十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS);十六烷基三甲基溴化铵(CTAB);常用的溶剂为非极性溶剂,如烷烃或环烷烃等。 表面活性剂一端是非极性的碳氢链(烃基),与水的亲和力极小,常称疏水基;另一端则是极性基团(如OH、COOH、NH2、SO3H等),与水有很大的亲和力,故称亲水基,总称“双亲分子”(亲油亲水分子)。 图 棕榈酸钠的两亲性结构 疏水基亲水基表面活性剂组成及分类 表面活性剂表面活性剂(surfacta
29、nt)是指具有固定的是指具有固定的亲水亲油基团,在溶液的表面能定向排列,亲水亲油基团,在溶液的表面能定向排列,并能使表面张力显著下降的物质。并能使表面张力显著下降的物质。表面活性剂组成分类阴离子表面活性剂:十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(DBS),双2乙基已基磺化琥珀酸钠(简称AOT)阳离子表面活性剂:十六烷基三甲基溴化铵(CTAB)非离子表面活性剂:TritonX 系列(聚氧乙烯醚类)临界胶束浓度(critical micelle concentration CMC) 表面活性剂在溶液中超过一定浓度时,会从单体(单个离子或分子)缔合成为胶态聚集物(分子有序组合体),即形成胶束束。
30、表面活性剂分子在溶剂中缔合形成胶束的最低浓度即为临界胶束浓度。亲亲油油端端在在内内、亲亲水水端端在在外外的的“水水包包油油型型”胶胶束束,叫叫“正正相胶相胶束束” 。 亲水端在内、亲油端在外的亲水端在内、亲油端在外的“油包水型油包水型”胶束,叫胶束,叫“反反相胶相胶束束”。胶束的形成过程胶束的形成过程胶束的变化过程胶束的变化过程介孔结构的制备1、粒径分布较窄,粒径可以控制; 2、选择不同的表面活性剂修饰微粒子表面,可获得特殊性质的纳米微粒; 3、粒子的表面包覆一层(或几层)表面活性剂,粒子间不易聚结,稳定性好; 4、粒子表层类似于“活性膜”,该层基团可被相应的有机基团所取代,从而制得特殊的纳米
31、功能材料; 5、表面活性剂对纳米微粒表面的包覆改善了纳米材料的界面性质,显著地改善了其光学、催化及电流变等性质 微乳液法制备的纳米材料的特点试剂试剂正硅酸乙酯( TEOS) 氨水环己烷正己醇 壬基酚聚氧乙烯(10) 醚(NP210) 水水油油助表面活性剂助表面活性剂非离子表面活性剂非离子表面活性剂1、利用、利用W/O 微乳液制备具有规则介孔结微乳液制备具有规则介孔结构的单分散球形纳米构的单分散球形纳米SiO2采用采用Schulman Schulman 法制备微乳液。法制备微乳液。将一定量的将一定量的NP210 NP210 、环己烷和氨水混合成乳状液、环己烷和氨水混合成乳状液, , 在搅拌下滴加
32、正己醇在搅拌下滴加正己醇, , 至体系变透明为止至体系变透明为止, , 得到得到W/OW/O微乳微乳液。液。将所得将所得W/OW/O微乳液在微乳液在30 30 恒温恒温, , 搅拌下加入定量的搅拌下加入定量的TEOSTEOS,水解水解5 h5 h。然后加入少量乙醇。然后加入少量乙醇, , 使使SiOSiO2 2形成絮状沉淀。形成絮状沉淀。离心分离离心分离, , 固体物用乙醇洗涤固体物用乙醇洗涤5 5 次次, , 于于60 60 真空干燥至真空干燥至恒重恒重, , 得到白色疏松粉末;得到白色疏松粉末;再高温焙烧再高温焙烧2 h , 2 h , 得到纳米得到纳米SiOSiO2 2 。制备过程:制备
33、过程:2、有序多级孔、有序多级孔硅酸盐介孔中空球的制备硅酸盐介孔中空球的制备Figure 1. Scanning electron micrograph showing the morphologyof the calcined sample3、微乳液法制备纳米钴颗粒、微乳液法制备纳米钴颗粒Reverse micelles of 5X10-2 M Co(AOT)2 form an isotropic phase. The amount of water added in solution is fixed to reach a water concentration defined as w
34、=H2O/AOT=32. Sodium borohydride, NaBH4, added to the micellar solution reduces the cobalt ions. The sodium borohydride content changes by varying the volume of a fixed concentration solution (NaBH4 ) 1 M) added to the micellar solution. R, the NaBH4 content, is defined as R=NaBH4/Co(AOT)2. Immediate
35、ly after NaBH4addition, the micellar solution color turns from pink toblack, indicating the formation of colloidal cobalt particles.Figure 1. TEMimages of cobalt nanocrystals made at varioussodium tetrahydroboride concentrations, R: (A) R=0.5, (B) R=1, (C) R=2, (D) R=4, (E) R=6, and (F) R= 8. The in
36、serts show TEM images obtained at a lower magnification.4、ZnO六边形盘和环的制备六边形盘和环的制备 For the preparation of ZnO discs and rings, a NaAOT microemulsion was first prepared by adding an aqueous solution of Zn(NO3)26H2O (0.025m) to a solution of NaAOT (0.10m) in 1-butanol and vigorously stirring for 2 h. The
37、 volume ratio of the aqueous phase to the organic phase was 10:1. Then a concentrated aqueous solution of NH3H2O (17.65m) with 4:1 molar ratio to Zn(NO3)26H2O was added dropwise to the well-stirred microemulsion. After addition was complete, stirring was continued for 3 h at room temperature. The re
38、sulting milky white mixture was subsequently kept at 70 or 90C for 5 days. 油油- -水体系水体系: : 丁醇水表面活性剂表面活性剂: : 琥铂酸二异辛脂磺酸钠(AOT) 影响因素影响因素温度温度影响因素影响因素AOT/丁醇丁醇1) No hexagonal ZnO disks were produced in the absence of NaAOT or when NaAOT was replaced with sodium dodecyl sulfate (SDS).2) The use of n-butanol
39、is also crucial to the formation of shape-controlled ZnO disks . No hexagonal ZnO disks are produced in the reaction if only water is used as solvent to dissolve NaAOT, or n-butanol is replaced with octane.影响因素影响因素Zn2+/NH3H2OHexagonal disks and rings are produced at Zn2+/NH3H2Omolar ratios of 1/3, 1/4, 1/5, and 1/6, but no ZnO particles were observed in a reaction carried out at a molar ratio of 1/2.