共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
碳酸钙/二氧化硅纳微复合粒子的高能球磨制备 总被引:1,自引:0,他引:1
采用高能球磨法制备了碳酸钙(纳米)/二氧化硅(微米)复合粒子.用X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、能谱分析仪(EDS)和傅里叶变换红外光谱仪(FT-IR)研究了球磨过程中复合粉体的相组成和微观组织;对碳酸钙/二氧化硅复合粒子的粒径、形态、结构进行了测定与表征.结果表明随着球磨时间的延长,复合粉体在强烈的冲击、挤压作用下逐渐细化和均匀化;球磨240 min可形成结合紧密的碳酸钙/二氧化硅复合粒子,并使之球形化;纳米碳酸钙均匀复合于二氧化硅的表面及其空隙,复合过程中没有产生新物质;强烈的机械力作用,使纳米碳酸钙表面晶体结构发生畸变,颗粒表面无定形化程度增加. 相似文献
3.
4.
5.
6.
<正>国内2000年前的球磨制备煤粉系统大多是由球磨机、低阻动态选粉机(细粉分离器和粗粉分离器)和电除尘器构成。近年来随着国家对环保越来越重视,该系统中所使用的电除尘器排放已经不能达标,且电除尘器的CO分析仪、防爆系统等的日常维护较为繁杂,费用也高。所以该系统中电除尘器的改造已成为必然的趋势。本文针对球磨制备煤粉系统的工艺流程结合电除尘器改袋除尘器的实例做具体介绍。1工艺流程介绍及电改袋前的准备 相似文献
7.
研究了一种适合430不锈钢发热器用BaO-Al2O3-SiO2-B2O3绝缘玻璃。结果表明:当BaO的质量分数在40%,SiO2在33%,Al2O3在10%,B2O3在5%,其它成分在6%时,可获得烧结温度在850~870℃,保温时间在10~15min,ρ(20℃)为3.2×1014Ω.cm,ρ(500℃)为1.07×108Ω.cm,耐压不低于2000V/80μm,膨胀系数在(8~8.5)×10-6/℃,抗热震性良好的430不锈钢用绝缘玻璃。研究了有机载体的成分与印刷厚度的关系。结果表明:采用合适的有机载体制备的绝缘介质浆料,印刷3次,烧结3次后,可获得80~90μm的印刷厚度。 相似文献
8.
利用软锰矿吸收硫酸镁热解尾气二氧化硫制得硫酸锰,再与碳酸氢铵室温下固相球磨反应,制备出前躯体碳酸锰,经热分解获得四氧化三锰。分别考察了物料比、球磨时间、球料比等因素对硫酸锰转化率的影响,采用XRD对产物进行了分析。结果表明,在n(碳酸氢铵)∶n(硫酸锰)=3.5∶1、球磨时间为40 min、球料质量比为5∶1时,硫酸锰的转化率可达99.8%,将固相产物在1 000 ℃热解1 h后所制备的四氧化三锰纯度为99.9%。该工艺操作简单,产品纯度高,成本低,为硫酸锰制备四氧化三锰提供了新的途径。 相似文献
9.
10.
11.
用高能球磨方法对BaO和TiO2混合粉末进行了机械力化学合成BaTiO3前驱体的试验研究,并借助于高分辨率透射电镜(HRTEM)进行了该前驱体的烧结性能研究。试验结果表明,随着球磨过程的进行,物料很快细化,随后发生晶体结构的变化。球磨30h后的X射线粉末衍射仪(XRD)图谱中发现了BaTiO3;球磨50h后,BaTiO3的特征峰相当明显。HRTEM测定结果证明,机械力化学活化的BaTiO3前驱体在1200℃下即可获得晶体发育完善、结构致密的烧结体。所得的烧结体的孔隙率达4.95%,平均孔径为50nm,体积密度达到其理论密度的95%左右,且具有较高的力学性能,抗折强度达500MPa以上。 相似文献
12.
13.
Ling Bing Kong Tian Shu Zhang Jan Ma Freddy Yin Chiang Boey 《Journal of the American Ceramic Society》2007,90(12):4055-4058
High-energy ball milling was applied to a commercial mullite powder, which had a particle size ranging from 2 to 10 μm, and was considerably refined to be <1 μm after milling for 10 h. Anisotropic grain growth of mullite was observed in the milled mullite powder, starting at relatively low temperatures (1200°C). The anisotropic grain growth was possibly attributed to the special anisotropic structure of mullite and refined mullite powder as a result of the high-energy ball milling, although other factors, such as lattice defects, localized stress of the milled powder, and impurities or contaminations caused by the high-energy milling also could be factors. This anisotropic grain growth of mullite might be useful in the fabrication of reinforced ceramics based on mullite and other materials. 相似文献
14.
高能球磨活化硬化水泥浆体的研究 总被引:2,自引:0,他引:2
研究了硬化水泥浆体的高能球磨机械力化学活化,借助于XRD、SEM和DTA等,测定了硬化水泥浆体的结构和力学性能随球磨时间的变化。试验结果表明,在球磨过程中.强烈的机械力作用首先使水泥石中的各水化物发生脱水作用。DTA测定结果证明,脱水程度随球磨时间的而增大,球磨至60min时,Ca(OH)2已完全脱水;同时,脱水温度随球磨时间而降低。进一步球磨使水化物的晶体结构发生严重的畸变和破坏,最终成为无定形态物质。球磨80min后粉体净浆的3d和28d抗压强度分别达28,33MPa和38.85MPa,说明硬化水泥浆体经高能球磨机械力活化后可重新作为胶凝材料使用。 相似文献
15.
Mg–SiC nanocomposite powders, with SiC particles of 50 nm size, were synthesized by mechanical alloying starting from a mixture of 80 vol.% pure Mg and 20 vol.% SiC powders. The effect of milling time on the microstructure properties of nanocomposite powders during mechanical alloying was investigated. The structural evolution during milling was monitored using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray mapping and X-ray diffraction methods. Using the Williamson-Hall equation, crystallite size and lattice strain of nanocomposite powders were estimated with broadening of XRD peaks. XRD results showed that the crystallite size of magnesium reached 49.52, 15.76 and 12.73 nm, respectively after 5, 15 and 25 h milling, also a uniform distribution of the SiC reinforcement in the Mg matrix was successfully obtained after milling the powders for 25 h. 相似文献
16.
Electrochemically active Sn-Si-C composite was synthesized by high energy ball milling(HEBM) in Ar atmosphere.The so-obtained composite was characterized by X-ray diffraction and field emission scanning electron microscopy.Lithium insertion/extraction characteristics of the composites were examined by constant current charge-discharge and cyclic voltammetry methods.The results show that there is no new alloy generated by HEBM.The composite synthesized by two-step HEBM resulted in initial lithium insertion s... 相似文献
17.
以Ti(SO4)2水溶液为前驱物,尿素为沉淀剂,采用水热沉淀法制备TiO2纳米粉体.利用XRD、TEM、DTA等分析测试手段对所得TiO2粉体的晶相组成、晶体形貌等性质进行了研究,讨论了晶粒尺寸与前驱物摩尔比、反应温度、保温时间之间的关系.结果表明,前驱物摩尔比为1∶2~1∶4,在140~200℃保温2~6h的水热条件下,可制得粒径为十几纳米的锐钛矿型TiO2晶体.实验得出,随着前驱物摩尔比减少、反应温度升高、保温时间延长,晶体粒径增大. 相似文献
18.
19.
Florin Vasiliu L. Diamandescu D. Macovei C. M. Teodorescu D. Tarabasanu-Mihaila A. M. Vlaicu V. Parvulescu 《Topics in Catalysis》2009,52(6-7):544-556
TiO2 nanopowders, doped with Fe3+ and Eu3+ were obtained by high-energy ball milling and their physical properties were investigated as a function of the doping content and ball milling time. A noticeable red shift and high photoactivity in the degradation and catalytic oxidation reactions of styrene and phenol were found for all doped specimens. 相似文献
20.