共查询到19条相似文献,搜索用时 203 毫秒
1.
固相法合成纳米氧化镁 总被引:36,自引:0,他引:36
以草酸和醋酸镁为原料 ,用室温固相化学反应合成出前驱配合物 ,前驱配合物在 60 0℃热分解 3h ,得到产物纳米MgO。用X射线粉末衍射、透射电镜对得到的产物进行表征。结果表明 ,固相法得到的纳米氧化镁为立方晶系结构 ,产物平均粒径为 15nm。作者以硝酸镁、碳酸钠为原料 ,用直接沉淀法合成得到纳米MgO ,平均粒径为 3 0nm。比较两种方法所得纳米氧化镁 ,固相法得到产物平均粒径比液相法小 相似文献
2.
3.
4.
纳米二硫化钼性能优越,用途广泛.介绍了纳米二硫化钼的3种合成方法:固相法、液相法、气相法.液相法中详细介绍了液相沉淀法、水热法和热溶剂法.另外介绍了纳米二硫化钼的应用研究现状,主要包括在润滑剂中和在复合材料中的应用研究.最后对纳米二硫化钼的合成及应用研究存在的问题及发展前景提出了看法. 相似文献
5.
纳米氧化镁粉体表面改性技术的研究进展 总被引:1,自引:0,他引:1
简述了纳米氧化镁表面改性的原因,并对纳米氧化镁的表面改性方法(物理改性和化学改性法):即表面包覆改性法、表面化学改性法、机械力化学改性法、沉淀反应改性法、外膜层改性(胶囊)法、和高能表面改性法进行了概述.着重介绍了表面活性剂、偶联剂在纳米氧化镁表面改性方面的应用,并对纳米氧化镁改性方面的研究提出了建议. 相似文献
6.
7.
8.
9.
10.
11.
介绍了近几年国内外以软化学方法制备纳米铁氧体的研究进展,分析了液相沉淀法、溶胶-凝胶法、低热固相法、微乳液法、流变相法等的特点,并对软化学法在纳米铁氧体制备中的应用进行了展望。 相似文献
12.
液相沉淀法是一种合成纳米粉体最为普遍的方法。介绍了液相沉淀法的三种方法:直接沉淀法、共沉淀法和均匀沉淀法。对液相沉淀法合成纳米粉体的沉淀反应过程、洗涤过程、干燥过程以及煅烧过程等环节的控制方法及原理作了详述。 相似文献
13.
Grain growth phenomenon of alumina in the presence of various quantities of liquid phase and magnesia was investigated at 1600°C, and the data were regressed by a statistical approach. The statistical result indicated that liquid phase, compared with magnesia, was a major factor in determining the grain growth mechanism of alumina. The alumina phase developed into faceted grains when the liquid phase was so abundant as to penetrate all the grain boundaries and junctions of alumina, whether with the doping of magnesia or not. This observation implied that magnesia, when co-existing with a large quantity of liquid phase, did not effectively reduce the degree of anisotropy in interfacial energy of alumina. Nevertheless, when its concentration was high enough to result in the precipitation of MgAl2O4, it avoided the evolution of elongated alumina grains by pinning the fast moving boundaries. 相似文献
14.
15.
纳米二氧化钛制备方法的研究进展 总被引:5,自引:0,他引:5
纳米二氧化钛作为一种重要的纳米材料,在陶瓷材料、催化剂载体等领域有着广泛的应用。简单介绍了纳米二氧化钛特性,综述了纳米二氧化钛的制备方法的特点和研究进展,包括气相反应法、液相反应法、固相反应法3大类,着重论述了目前应用比较广泛的液相法(又可以细分为水解法、沉淀法、溶胶-凝胶法等方法)。并在此基础上分析了目前纳米二氧化钛制备方法在中国的发展现状、特点及不足。同时指出今后纳米二氧化钛制备方法发展的方向是提高对粒度控制能力及做好对团聚体的分散及控制。另外,纯度控制,化学成分,微观结构的均匀性控制,稳定性控制也是急需解决的问题。 相似文献
16.
简单介绍了纳米氧化镁的国内外研究现状,制备纳米氧化镁的方法,粗略提了一下表面改性,较详细地介绍了影响纳米氧化镁粒径的因素,最后展望了一下今后有关纳米氧化镁的国内主要研究内容和主攻方向. 相似文献
17.
《Ceramics International》2022,48(1):427-435
The microporous refractory with low thermal conductivity shows a promising application prospect as tundish lining. In this study, the interactions between microporous magnesia aggregates and oxide inclusions in steel were explored. The experimental results and thermodynamic calculation show that the interaction process of microporous magnesia aggregates and oxide inclusions at high temperature can be divided into dissolution, reaction and post-reaction. The microporous magnesia aggregates can absorb the inclusions in steel by reaction and liquid phase penetration. The microporous magnesia aggregates have a strong adsorption for Al2O3 and TiO2. Moreover, the microporous magnesia aggregates mainly absorb SiO2 by penetration, but excessive SiO2 will lead to the serious corrosion of microporous magnesia aggregates. 相似文献
18.
采用液相沉淀法制备了纳米氧化锌,分别用X射线衍射分析(XRD)、紫外可见吸收光谱(UV-Vis)、红外光谱等物理手段对纳米氧化锌进行了表征,并运用抑菌圈法对所制备的纳米氧化锌进行了定性的抗菌性研究。结果表明,制备的纳米氧化锌颗粒大小均匀,分散性较好,对金黄色葡萄球菌和大肠杆菌有良好的抑制效果。 相似文献
19.
The solid solubility of magnesia in magnesium aluminate spinel and magnesium aluminate spinel in magnesia does not change with temperature thus not creating bonds or precipitation over periclase grains in a single stage sintering process. In comparison, the precipitated spinels in magnesia-chromia refractories form complex spinel due to inversion in the position of bivalent and trivalent cations within the structure, making them more stable at high temperature than either normal or inverse spinel. Additives form low-temperature compounds that diffuse into the spinel structure and create defects that change the properties of spinel solid solution. In the present study, magnesia and alumina powders along with tetravalent oxide additives were analyzed for their role in reactive densification of spinel in a single stage firing process in order to achieve a better binding system for magnesia-based refractories. These tetravalent oxides on reaction with magnesia form spinel solid solution with MgAl2O4 as they have similar crystal structure. The spinel solid solution formed using oxide additives is expected to have higher solubility in magnesia than magnesium aluminate spinel, resulting in improvement of the bonding during sintering through increased in solid solubility at elevated temperatures followed by precipitation of secondary spinel phases, similar to the complex spinel in magnesia-chrome refractories. The formation of spinel during firing remains as a second phase that retards the grain growth of periclase. The changes in unit cell dimensions with temperature and amount of additive were analyzed using Reitveld method and correlated with the densification behaviour at different temperatures. 相似文献