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采用O/W/O多重乳液法, 以液体石蜡为内核, 氧化铝溶胶为外壳层组成的复合液滴作为前驱体, 制备毫米级氧化铝空心球, 研究了装置几何结构对前驱体的形成和固化过程对空心球结构的影响。结果表明, 内部油相通过直流通道直接注射到水相液滴内部时, 形成的复合液滴具有均一核壳结构, 壁厚和直径在30~80 μm和800~2200 μm可控。液滴置于水平方向旋转固化, 保持转速在20~60 r/min, 所得凝胶球可以保持完整的球形度和核壳结构。1200℃高温煅烧制备出的氧化铝空心微球维持高的球形度和空心结构, 表面粗糙度大约22 nm, 壁厚达到几十微米, 直径达到毫米级, 主要晶型为稳定的α-Al2O3。 相似文献
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《无机材料学报》2016,(3)
采用O/W/O多重乳液法,以液体石蜡为内核,氧化铝溶胶为外壳层组成的复合液滴作为前驱体,制备毫米级氧化铝空心球,研究了装置几何结构对前驱体的形成和固化过程对空心球结构的影响。结果表明,内部油相通过直流通道直接注射到水相液滴内部时,形成的复合液滴具有均一核壳结构,壁厚和直径在30~80mm和800~2200mm可控。液滴置于水平方向旋转固化,保持转速在20~60 r/min,所得凝胶球可以保持完整的球形度和核壳结构。1200℃高温煅烧制备出的氧化铝空心微球维持高的球形度和空心结构,表面粗糙度大约22 nm,壁厚达到几十微米,直径达到毫米级,主要晶型为稳定的a-Al_2O_3。 相似文献
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SiO2空心微球的制备与表征 总被引:2,自引:0,他引:2
以自制的微米级碳酸钙颗粒为模板,正硅酸乙酯为硅源,通过溶胶-凝胶方法合成出CaCO3/SiO2核壳结构;随后通过高温煅烧、酸浸和干燥处理,制备出圆形度高、分散性好、结构完整的微米级SiO2空心球。并利用SEM、XRD、FTIR、TG和压缩实验等方法对空心微球的形貌、结构和抗压强度进行了分析和测定。SiO2空心微球的粒径为2-5μm,壳层厚度为0.42-0.85μm,比表面积为554.01m^2/g,最可几孔径为1.7nm,抗压强度在20~30MPa之间。 相似文献
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本文基于喷雾干燥过程的基本理论,以煅烧高岭土为原料,采用喷雾干燥法制备高岭土生坯微球。探讨了浆料浓度、进口温度、喷雾压力等工艺因素对微球的粒径与形貌的影响。研究了喷雾干燥成型的机理。通过实验优化工艺参数,得到在喷雾压力1.2MPa时,保持进口温度140℃不变,对浓度为25%的高岭土浆料进行喷雾干燥造粒得到的微球球形度最好,粒径分布最均匀。对高岭土微球进行二次烧结可以制得高强度、高硬度、表面光滑的单分散陶瓷微球。本技术为微米级陶瓷微球的制备提供了新的方法。 相似文献
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正辛胺模板法制备Si/Al复合空心微球及其结构表征 总被引:1,自引:0,他引:1
以正辛胺为模板、正硅酸乙酯(TEOS)为硅源、异丙醇铝为铝源,在盐酸的催化作用下通过溶胶一凝胶方法制备出圆形度和分散性好、结构完整的Si/Al复合空心微球.分析了不同反应时间和反应温度下Si/Al复合空心微球的形貌、粒径、成分和结构.结果表明:Si/Al复合空心微球的平均粒径随反应温度和反应时间的增加而缓慢增大,但明显小于同样条件SiO2空心微球的粒径.Si/Al复合空心微球的平均粒径为8~16μm,壳层厚度为2.18~3.61μm.Si/Al复合空心微球中的铝主要以氧化物的形式存在;壳层表面具有微孔结构,比表面积为431~912 m2/g;可几孔径为1.2~2.0nm. 相似文献
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采用模板法制备了可控制球壳厚度的亚微米二氧化钛空心微球.首先利用钛酸四丁酯乙醇溶液和聚苯乙烯粒子制备了二氧化钛/聚苯乙烯复合粒子,在空气中经500℃煅烧除去苯乙烯模板后得到锐钛矿二氧化钛空心微球.透射电镜和扫描电镜观察表明,二氧化钛/聚苯乙烯复合粒子煅烧后体积发生了急剧的收缩,形成具有空心结构二氧化钛微球.电子衍射和X射线衍射分析可知空心微球的二氧化钛球壳为锐钛矿.实验发现当钛酸四丁酯与乙醇的体积比从120提高到110时,二氧化钛空心微球的球壳厚度从20~25 nm增加到45~50nm;以不同粒径的聚苯乙烯粒子作模板,可以得到不同内孔直径的二氧化钛空心微球,其内孔直径比聚苯乙烯模板直径小15%~20%. 相似文献
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以分散聚合法制得的单分散阳离子聚苯乙烯(PS)微球为模板,钛酸丁酯为前驱体,采用溶胶-凝胶法在模板表面包覆TiO2壳层,并在不同煅烧温度下制备了晶相结构不同的微米级中空TiO2微球。采用TEM、SEM、FT-IR、XRD、UV-Vis DRS对样品的微观结构、相态组成及光催化性能进行了表征。结果表明TiO2中空微球平均粒径达到1.23μm,壳层厚度约为30nm;随着煅烧温度增加,锐钛矿晶粒尺寸会增加,并在700℃时出现混晶结构;在500℃煅烧得到的TiO2中空微球对甲基橙(MO)降解表现出比P25更好的光催化性能及光催化稳定性。 相似文献
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为了使铝工业废水达标排放,回收废水中的铝,以NaOH为沉淀剂,通过控制不同pH值,采用化学分步沉淀法对铝工业废水进行处理,同时对所产生的沉淀物Al(OH)3经过干燥、焙烧进行资源化研究,采用粒径测定仪和红外光谱对所得产物进行了分析检测.研究表明:废水处理后得到的Al(OH)3凝胶在干燥15~25 h、焙烧温度1150℃、焙烧7 h的条件下,可得氧化铝粉末,该粉末产品经粒径检测、红外谱图分析,证明所得氧化铝为α-Al2O3,且粒径在227~309 nm范围内.铝工业废水经过分步沉淀处理后,达到国家废水排放标准,废水中的铝以α-Al2O3的形式回收. 相似文献
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以分散聚合法制备的聚苯乙烯(PS)微球作为模板,通过均相沉淀法制备前驱体PS-Gd(OH)CO_3复合微球,高温煅烧后得到Gd_2O_3空心微球,将其与丁基橡胶复合制备低频高阻尼Gd_2O_3/丁基橡胶复合材料。采用FTIR、SEM、TEM分析、TG分析仪、XRD分析和XPS对Gd_2O_3空心微球的形貌与结构组成进行表征。将Gd_2O_3空心微球与粉体分别作为填料加入丁基橡胶中制备Gd_2O_3/丁基橡胶复合材料。结果表明:Gd_2O_3空心微球由立方萤石结构的颗粒组成,外空心直径为0.9μm,壳层厚度约为100nm;添加空心微球的复合材料阻尼性能较好;与纯丁基橡胶相比,Gd_2O_3/丁基橡胶复合材料的低频阻尼性能明显提高。 相似文献
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Reactive infiltration of a NiO-base blended powder with molten aluminium was attempted at 1673 K in order to obtain Al2O3
matrix composites containing a dispersion of Al3Ni, AlNi and/or AlNi3. The NiO powder was barely infiltrated by the molten
aluminium after a 3600 s holding time at 1673 K. A continuous layer of Al2O3 was observed to exist at the infiltration front,
which prevented any further infiltration. TiB2 particles were added to the NiO powder in order to absorb the heat of reaction
between NiO and aluminium. When the TiB2 particle content in the [NiO+TiB2] powder blend was greater than 20 vol%, spontaneous
infiltration occurred completely. Thus, it was shown that the addition of the TiB2 particles assisted in the spontaneous infiltration.
The specimens produced by the in situ reaction consisted of Al2O3, TiB2 and Al3Ni. Al3Ni was mainly located between the TiB2
and Al2O3. The effect of the TiB2 addition on the infiltration kinetics was to decrease the maximum attainable temperature
caused by the exothermic reaction. This in turn prevented the formation of a continuous Al2O3 film at the infiltration front.
This resulted in the production of pathways for the infiltration of the molten aluminium and made possible the complete infiltration.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
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Alpha-Fe2O3 hollow micospheres have been successfully synthesized by solvothermal method at 200 degrees C. The synthesized products are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and the nitrogen adsorption-desorption isotherm technique. The alpha-Fe2O3 hollow microspheres have an average diameter of 2-3 microm, the shell consists of numerous aligned nanorods with length of about 200-400 nm. The effects of solvent and reaction time have been studied. The Ostwald ripening mechanism is proposed to account for the formation of alpha-Fe2O3 hollow microspheres. Because of the porous hollow microstructure and large specific surface area, the microspheres were found to be effective sorbents for the removal of Cr(VI) ions from wastewater. 相似文献
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Using a domestic microwave oven, pellets of a silica–aluminium powder were ignitedand a self-propagating high-temperature synthesis (SHS) reaction occurred to produce Si+AlN+Al2O3 as the resultant phases. Silicon AlN and Al2O3 were subsequently nitrated to synthesize sialon phases under a nitrogen atmosphere without cooling. Thus both the SHS process and the nitration were finished within one-step process, which could save processing time and energy. © 1998 Kluwer Academic Publishers 相似文献
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Anodization is an effective surface treatment for improving the corrosion resistance of aluminium-matrix composites. For SiC particle-filled aluminium, anodization was performed successfully in an acid electrolyte, as usual. However, for AlN particle-filled aluminium, anodization needed to be performed in an akaline (0.7 N NaOH) electrolyte instead of an acid electrolyte, because NaOH reduced the reaction between AlN and water, whereas an acid enhanced this reaction. The concentration of NaOH in the electrolyte was critical; too high a concentration of NaOH caused the dissolution of the anodizing product (Al2O3) by the NaOH, whereas too low a concentration of NaOH did not provide sufficient ions for the electrochemical process. The corrosion properties and anodization characteristic of pure aluminium, Al/AlN and Al/SiC were compared. Without anodization, pure aluminium had better corrosion resistance than the composites and Al/SiC had better corrosion resistance than Al/AlN. After anodization, the corrosion resistance of Al/AlN was better than Al/SiC and both composites were better than pure aluminium without anodization, but still not as good as the anodized pure aluminium. 相似文献
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Weiquan Cai Shuanggui Chen Jiaguo Yu Yuzhen Hu Chengxiong Dang Shuhua Ma 《Materials Chemistry and Physics》2013
Three-dimensional hierarchical boehmite hollow microspheres with a very high yield at low cost were successfully synthesized via a one-pot template-free solvothermal route using aluminum chloride hexahydrate as precursor in a mixed ethanol–water solution with assistance of trisodium citrate. The as-synthesized products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption/desorption techniques. The results show that Cl− and addition amount of trisodium citrate have significant effect on the morphologies of the resultant products, and 6–8 mmol of trisodium citrate is optimal for the synthesis of boehmite hollow microspheres assembled from randomly interconnecting and aligned nanorods with solvothermal time no less than 15 h. A synergistic mediation mechanism of citrate ions and Cl− to form boehmite hollow spheres via self-assembly morphology evolution was proposed based on the experimental results. Interestingly, the typical boehmite hollow microspheres with a surface area of 102 m2 g−1, pore volume of 0.37 cm3 g−1, and the average pore size of 14.6 nm show superb adsorption properties for Congo red with maximum capacity of 114.7 mg g−1 which is higher than that of a commercial boehmite. This simple synthetic route is a very promising way for the design and synthesis of new functional hierarchical nanostructured materials with desired adsorptive properties. 相似文献
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We fabricated an orderly inclined Al2O3 column array using a hollow microsphere template. The microstructure and optical properties were investigated with scanning electron micrography and a UV/VIS spectrometer, respectively. Microsphere shell templates were formed using atomic layer deposition to prevent the melting of polystyrene microspheres during the following high-temperature deposition process. An inclined Al2O3 column array with a 30° tilt angle was grown by oblique deposition on a substrate with a 75.5° tilt angle with respect to the substrate normal. Birefringence and photonic crystalline behavior can be observed in the orderly inclined column array. The difference in the refractive indices between the p and s polarizations of the orderly inclined Al2O3 column array was about 0.1. The photonic properties of the crystal were enhanced compared to those of substrates without patterns. 相似文献
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Yang X Song X Wei Y Wei W Hou L Fan X 《Journal of nanoscience and nanotechnology》2011,11(5):4056-4060
In this work, cage-like ZrO2 and hollow ZrO2 microspheres with high surface area and strong adsorption capability were successfully synthesized by microwave- ethanol-thermal method using yeasts as bio-template. XRD, SEM, EDS and BET were used to characterize the products. The results show that these micropheres have a size of about 2-3 microm and are composed by ZrO2 particles of 30-40 nm. The maximum specific surface area of them can reach to 384.780 m2/g and there are presences of the inhomogeneous mesopores. Moreover, the template can be removed and tetragonal phase ZrO2 can be obtained without using calcinations, which greatly simplifies the experimental procedure. We also studied the adsorption capability of cage-like ZrO2 and hollow ZrO2 microspheres to methyl orange, the highest adsorption percent was up to 99.5%. The adsorption isotherm conforms to Freundlich equation. 相似文献