共查询到20条相似文献,搜索用时 78 毫秒
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机械力化学法制备单相莫来石的机理研究 总被引:3,自引:0,他引:3
以高岭土和氢氧化铝为原料,采用机械力化学法制备出了单相莫来石。用热重-差示扫描分析研究了混合粉体经高能球磨后的结构变化,并讨论了单相莫来石的形成机理。结果表明:高能球磨破坏了混合物的晶体结构;随着粉磨的进行,混合物的比表面积会增加,无序程度也会增加,键能会减小,从而导致了内部贮能的增加,反应活化能的减小,并可得到均匀混合物。粉磨30h混合物制成的烧结体的热膨胀系数要比未粉磨的低约20%。 相似文献
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以MnO2、Fe2O3和ZnO为原料,采用机械力化学法制备锰锌铁氧体粉体.研究结果表明:颗粒粒径减小主要发生在初期,随着粉磨时间的增加,细颗粒会凝聚成团聚体,破碎与凝聚过程最后达到动态平衡;高能球磨可使原料比表面积变大,无序程度增加,键能减小,从而导致内部贮能的增加,并可得到均匀混合物,能更大程度地促进化学反应.高能球磨40h的物料,在相对较低的温度下(1200℃)煅烧即可生成单相锰锌铁氧体.对于未粉磨的样品,温度必须要达到1400℃. 相似文献
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机械力化学法制备纳米晶体的研究进展 总被引:1,自引:0,他引:1
介绍了机械力化学的概念、作用机理及其表征技术。阐述了机械力化学制备纳米粉体的机理和优越性,并主要以BaTiO3纳米晶为例研究其合成方法及反应机制。还对其未来发展进行了展望。 相似文献
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本文在实验室自制的振动磨机中,对不添加硬脂酸和添加硬脂酸两种情况下的石英砂物料进行粉磨研究,结果发现,当添加硬脂酸时,不仅可以阻止颗粒的聚集,增加颗粒的分散性,提高粉碎的效率,而且能降低粉体的表面能,使粉体从极性状态朝非极性状态改变,从而得到疏水亲油的功能性粉体。木文还在此基础上提出一种深度加工无机填料的新方法。 相似文献
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机械力化学制备陶瓷材料的研究进展 总被引:7,自引:0,他引:7
在球磨过程中机械力化学使颗粒和晶粒细化产生裂纹,比表面积增大,晶格缺陷增多,晶格发生畸变和非晶化,乃至诱发低温化学反应,可制备出高活性陶瓷粉体和性能优异的陶瓷基材料。介绍了机械力化学在陶瓷材料研究中的最新研究进展。同时,还讨论了不同球磨工艺条件对材料制备过程的影响;并对其未来发展进行了展望。 相似文献
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采用溶胶-凝胶法制得溶胶后,600℃下煅烧制得了TiO2粉体。通过偶联剂的媒介,将功能高分子聚乙烯亚胺(PEI)接枝到钛胶表面,制备二氧化钛分子印迹的前躯体。并用透射显微镜(TEM)对样品粒径进行表征。结果表明:所制备的颗粒平均粒径为30~60nm。通过实验发现反应以乙腈为溶剂,按PEI/TiO2质量比15∶1为最佳条件。最后通过红外分析,对制备的前躯体进行表征,发现聚乙烯亚胺已接枝到钛胶表面。 相似文献
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This paper presents the results obtained with heterogeneous catalytic ozonation in which model and natural waters are ozonated in the presence of supported titanium dioxide (TiC2) as a solid catalyst. The conditions in preparing the supported catalyst are experimentally optimized. The efficiencies of three catalyst supports (attapulgyte, alumina and silica gel) for organic matter oxidation have been compared. The TiC2 supported in alumina calcined at 500[ddot]C compacted to granular form with a particle diameter about 2-4 mm is demonstrated to be the best catalyst on the removal total organic carbon (TOC) by ozone. 相似文献
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PET聚酯缩聚用改性二氧化钛催化剂的制备研究 总被引:3,自引:3,他引:0
设计并制备了一种表面硅烷偶联剂KH560改性的二氧化钛,并用红外、透射电镜、XRD粉末衍射和N2吸附比表面积对其进行表征。该催化剂是由许多很小的无定形二氧化钛粒子组成的团聚体,其表面富含大量的羟基。该催化剂较Sb2O23的催化活性高许多,而且所得产品的色相较未改性的二氧化钛有明显的改善。 相似文献
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The development of green technologies for the manufacture of various materials is considered as one of the approaches to address some of the environmental issues of commercializing new materials. A mechanochemical (MC) method is developed to synthesize crystalline porous material‐5 (CPM‐5). The effect of different mechanical parameters, including oscillation frequency and time and the number of metal balls used for milling is studied. Results revealed that CPM‐5 crystals are successfully formed under optimized conditions. It was noted that the thermal treatment of the samples after grinding is very crucial for the formation of CPM‐5 under the studied conditions. Moreover, washing of samples with a 1:1 solution of dimethylformamide (DMF):H2O remarkably enhanced the surface area of the final product. 相似文献
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To improve the safety of HMX, HMX/TATB composite particles were prepared using a mechanochemical approach. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR) and X‐ray diffraction (XRD) were employed to characterize the HMX particles before and after being coated. The results showed that the HMX particles were coated by submicrometer‐sized TATB particles. The crystal form of HMX maintained unchanged during the whole preparing process. The decomposition characteristics of HMX/TATB composite were investigated by DSC, showing that the decomposition peak temperature increased by 5.141 °C, while the phase transition temperature decreased by 4.064 °C. Compared with the uncoated HMX particles, the impact and friction sensitivities were decreased by 56.1 and 70 %. Moreover, the grinding mechanism was investigated and discussed. 相似文献
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María P. Ormad Natividad Miguel Munia Lanao Rosa Mosteo José L. Ovelleiro 《臭氧:科学与工程》2010,32(1):25-32
The aim of this research work is to study the influence of hydrogen peroxide and titanium dioxide in the ozone-based treatment to degrade 44 organic pesticides present in natural water, which are systematically detected in the Ebro River Basin (Spain). The studied pesticides are: alachlor, aldrin, ametryn, atrazine, chlorfenvinfos, chlorpyrifos, pp'-DDD, op'-DDE, op'-DDT. pp'-DDT, desethylatrazine, 3,4-dichloroaniline, 4,4'-dichlorobenzophenone, dicofol, dieldrin, dimethoate, diuron, α-endosulphan, endosulphan-sulphate, endrin, α-HCH, β-HCH, γ-HCH, δ-HCH, heptachlor, heptachlor epoxide A, heptachlor epoxide B, hexachlorobenzene, isodrin, 4-isopropylaniline, isoproturon, metholachlor, methoxychlor, molinate, parathion methyl, parathion ethyl, prometon, prometryn, propazine, simazine, terbuthylazine, terbutryn, tetradifon and trifluralin. The ozonation using 3 mg O3 L?1 produces a pesticides removal close to 23%, whereas the application of O3/H2O2 and O3/TiO2 treatments achieves average degradation yields lower than the ozonation. However, the application of O3/H2O2 /TiO2 process improves considerably the pesticides degradation and an average degradation yield of 36% is obtained. 相似文献