共查询到19条相似文献,搜索用时 62 毫秒
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本文以钛酸四丁酯、冰醋酸、盐酸、六水合硝酸锌为主要原料,采用溶胶-凝胶法,以去离子水作为溶剂制备出具有钛铁矿结构的纯六方相ZnTiO3粉体,并利用TG/DTA,XRD,FE-SEM和FT-IR对其组织结构和形貌进行了研究。实验结果表明:前驱体干凝胶在550℃热处理4h可制得纯六方相ZnTiO3,且六方相稳定存在的温度范围相对较宽,从550℃到900℃。当温度升高到950℃后,六方相ZnTiO3将分解为立方相Zn2TiO4和金红石相TiO2。在550℃热处理制得的ZnTiO3粉体粒径约为50nm。 相似文献
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将溶胶-凝胶法与微乳液化学剪裁法相结合,以钛酸丁酯和氯化锌制备凝胶,在OP-10-SDS/正丁醇/环己烷/水复配微乳体系中进行化学剪裁制备前驱物,再经煅烧制备了组成单一的球状纳米ZnTiO3粉体,通过XRD、TEM、SEM、TG-DSC等方法对产物进行了表征,并讨论了凝胶的陈化时间、煅烧温度和煅烧时间对纳米ZnTiO3的组成、粒径和形貌的影响,提出了纳米ZnTiO3可能的形成机理。结果表明,在700℃煅烧2h制备的纳米ZnTiO3平均粒径为35nm,粒径分布比较均匀,基本呈单分散;适当延长陈化时间会减少ZnO及TiO2杂质;随着煅烧时间的延长,ZnTiO3晶体粒径开始增大;煅烧温度过高会使六方相ZnTiO3分解为立方相的Zn2TiO4和金红石型TiO2。 相似文献
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通过购买市售的几种不同生产厂家的纳米二氧化硅,分别对其做扫描电镜(SEM)分析、红外光谱(IR)分析和X射线衍射(XRD)分析,以了解纳米二氧化硅的表面及内部微观结构信息。分别用化学沉淀法和溶胶—凝胶法制备粒径在70 nm左右的二氧化硅粉末,并对两种方法的优缺点和制得的产品质量进行比较。改变反应物浓度、乙醇水体积比和表面活性剂的种类等条件,比较制得的二氧化硅粉末质量,以确定最优的制备方法。 相似文献
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将溶胶-凝胶法与微乳液化学剪裁法相结合,以钛酸丁酯和氯化锌制备凝胶,在OP-10-SDS/正丁醇/环己烷/水复配微乳体系中进行化学剪裁制备前驱物,再经煅烧制备了组成单一的球状纳米ZnTiO3粉体,通过XRD、TEM、SEM、TG-DSC等方法对产物进行了表征,并讨论了凝胶的陈化时间、煅烧温度和煅烧时间对纳米ZnTiO3的组成、粒径和形貌的影响,提出了纳米ZnTiO3可能的形成机理。结果表明,在700℃煅烧2h制备的纳米ZnTiO3平均粒径为35nm,粒径分布比较均匀,基本呈单分散;适当延长陈化时间会减少ZnO及TiO2杂质;随着煅烧时间的延长,ZnTiO3晶体粒径开始增大;煅烧温度过高会使六方相ZnTiO3分解为立方相的Zn2TiO4和金红石型TiO2。 相似文献
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以无水醋酸铅和钛酸丁酯为原料,采用溶胶-凝胶法制备了钙钛矿型纳米钛酸铅(PbTiO3)粉体。利用X射线衍射(XRD)、粒度测试、扫描电镜(SEM)等分析测试手段,对制备的钛酸铅纳米粉体的结构、性质和形貌进行了表征,并讨论了影响溶胶-凝胶过程的诸因素。研究结果表明:无水乙醇、水解温度、丙三醇和热处理温度等因素均对溶胶-凝胶过程有明显的影响,其中反应温度对胶体形成时间的影响最明显。钙钛矿型钛酸铅晶体在450 ℃时形成,随着热处理温度的升高,粉体的物相组成也将发生变化。钛酸铅干凝胶在600 ℃热处理2 h后可以得到结晶程度很高、平均粒径为53.7 nm、颗粒大小分布均匀的纳米钛酸铅粉体。 相似文献
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以ZnSO4·7H2O和Na2CO3为原料,采用化学法合成了ZnO超微粉末。应用X射线粉末衍射法(XRD)测定了合成ZnO的几组晶面的衍射峰形,经数据处理得到ZnO超微粉末的平均晶粒度和晶格畸变率的定量分析结果。实验结果表明,化学法合成的ZnO超微粉末的晶粒度范围在20nm~35nm之间。 相似文献
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Synthesis and Characterization of Nanoscale Mullite Powder 总被引:1,自引:0,他引:1
ZHAOHuizhong HUShoutian WANGHouzhi ZHANGWenjie 《中国耐火材料》2003,12(4):20-24
Nanoscale mullite powder were synthesized via solgel-SCFD and middle temperature treatment by using AIP (aluminum-isopropoxde)and TEOS(tetraethyl orthosilicate) as starting materials.Both of the binary aerogel of alumina-silica and calcined nanoscale materials were investigated by using TG-DSC(thermogravimetry-differential scanning calorimeter),TEM(transmission electron microscope),XRD(X-Ray diffractometer)and specific surface area and porosimetry.TG-DSC indicated the removal of most of the volatiles,i.e.15.98% up to about 700℃,and in the DSC curve,existence of two exothermic peak at about 445℃ and 1015℃ may be due to the crystallization of Si-O-Al-O in diphasic gels and mullitization and a small endothermic peak at about 805℃ indicated the decomposition of structural water molecules.On the colligation of the results of TG-DSC,XRD and TEM,the beginning temperature of mullitization in Al2O3-SiO2 aerogel system can be confirmed at about 1015℃.XRD results also showed the formation of mullite at the range 1100-1200℃.TEM and surface area and porosimetry results showed that the nanosized mullite were calcinated at 1100 and 1200℃ exhibited size 30nm and 50nm,specific surface area 138.91m^2/g and 95.81m^2/g. 相似文献
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微斜长石粉体水热合成六方钾霞石及其表征(英文) 总被引:3,自引:0,他引:3
在KOH溶液浓度为6~10mol/L,水热反应温度为240~280℃,反应时间为2~8h的条件下,研究了以微斜长石粉体为原料水热合成六方钾霞石的可行性。X射线衍射分析结果表明:合成产物为纯相的六方钾霞石,没有非晶态物质和其它KAlSiO4的多型。Fourier变换红外光谱、29Si和27Al MAS核磁共振分析表明合成的六方钾霞石晶体结构中Si和Al是完全有序的。扫描电子显微镜研究结果表明:合成产物的形态为六方板状,晶粒尺寸约为800~1000nm。与其它合成六方钾霞石的方法相比,本方法原料来源广泛,成本低廉,合成条件温和,工业应用前景广泛。 相似文献
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Synthesis and Characterization of a High-Purity AlN Powder 总被引:1,自引:0,他引:1
IRVIN C. HUSEBY 《Journal of the American Ceramic Society》1983,66(3):217-220
High-purity AIN powder was synthesized by preparing high-purity (NH4 )3 AIF6 , decomposing the (NH4 )3 AIF6 to AIF3 , and reacting the AIF, at 800° to 1000°C with high-purity NH3 . AIN powders could be synthesized with a cation purity of 99.99% and an oxygen content <0.2 wt%. The specific surface area depended on the process conditions and varied from 0.2 to 2.6 m2 /g. The thermodynamics of the process are evaluated and the influence of various process parameters on the resulting powder characteristics are described. 相似文献
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High titanium-loading hexagonal mesostructured silica thin films (Ti-HMSTF) have been successfully synthesized by carefully controlling two factors. One is the hydrolysis and condensation reaction of titanium alkoxide and the other is the aging condition of as-made Ti/Si mixed thin films. The former was controlled by adding acetylacetone (AcAc) as a Ti chelating agent. Regarding the latter, aging under a hydrothermal water vapor ambient environment was found to be effective in synthesizing Ti-HMSTFs with well-defined mesostructures. The maximum molar ratio of Ti/Si in the Ti-HMSTF materials attained a value of 0.3 (referred to as Ti-HMSTF-0.3) for the as-made films. These materials were subjected to a specific hydrothermal aging process, which was prepared from a precursor solution containing AcAc with the molar ratio AcAc/Ti=1. Small angle X-ray diffractometry (SA-XRD) and transmission electron microscopy (TEM) demonstrated that Ti-HMSTF-0.3 had a highly ordered 2-dimensional hexagonal mesostructure. This 2D hexagonal mesostructure was thermally stable even after the removal of the triblock copolymer template by calcination at 450°C for 4 h. Moreover, small amounts of TiO2 anatase nanocrystals with a size of about 3 nm were formed in the calcined Ti-HMSTF-0.3. O(1s) X-ray photoelectron spectroscopy (XPS) analysis indicated that the incorporation of titanium into the HMSTF was through the Si–O–Ti bonds. The Ti(2p) XPS showed that the binding energy of the titanium in HMSTF decreased with increasing Ti loading. 相似文献