共查询到20条相似文献,搜索用时 156 毫秒
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综述了目前制备高纯Al2O3超细粉体的三大类方法,对其中应用和研究最多的液相化学合成法的各种方法作了较详细的介绍,分析了各种方法的优缺点。简述了高纯Al2O3超细粉体的特性及应用。 相似文献
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表面包覆改性技术在陶瓷技术中的应用 总被引:19,自引:1,他引:18
包覆改性技术对于解决超细粉特别纳米尺寸粉体的团聚问题,改善粉体表面性能有着重要作用,本文阐述包覆改性技术在制备新型陶瓷中的运用,介绍了基本表面包覆改性技术,同时介绍当前在制备新型陶瓷中人们运用表面包覆改性技术的进展情况。 相似文献
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表面活性剂在陶瓷超细粉体制备中的应用 总被引:13,自引:0,他引:13
表面活性剂是一类加入少量就能使物质性质发生很大变化的精细化工产品。陶瓷超细粉体的制备可分为长大法和细碎法,本文主要概述了表面活性剂在细碎法中作助磨剂,对长大法中颗粒团聚的改善等的机理和应用。 相似文献
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在NdFeB磁粉表面包覆金属层是改变其性质的有效手段,但目前常用的化学沉积法、电化学沉积法与化学气相沉积法等都无法实现磁粉表面完整、牢固的包覆.探索新的NdFeB磁粉表面金属完整包覆技术具有重要的理论意义及应用价值.根据NdFeB片状磁粉在磁场下的磁化特征,设计了磁力搅拌流化床电解槽,利用电沉积实现磁粉表面的纳米金属层包覆.测量了磁粉包覆前后的磁性能和电极电位,测定了包覆不同厚度Cu对磁粉制成粘结磁体抗压强度的影响.结果表明,利用磁力搅拌流化床电沉积法可以实现NdFeB磁粉的完全包覆,包覆层厚度可以控制在纳米尺度.磁粉包覆后的磁性能和电极电位发生了明显改变,包覆铜样品的粘结磁体抗压强度明显提高. 相似文献
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Tungsten carbide powders sputter-deposited with stainless steel were characterized in order to evaluate the surface properties in air and aqueous environments. The scanning electron microscopy with energy dispersive spectroscopy showed that a very high uniformity of the coating distribution on the WC particles was attained by the sputtering technique, enabling a complete surface coverage for low coating contents (? 1 wt.%).The DTA-TG thermal analysis in air atmosphere revealed that the coating layers increase the oxidation resistance of WC powders, in spite of the coating porosity.The electrophoretic measurements performed in aqueous solution, for different pH at a constant ionic strength (1 mM KCl), showed that the surface charge until pH ? 8 is essentially determined by the stainless steel coating, while for higher pH it becomes closer to that of the WC particles. The coating adhesion measured by a scratch test was found to decrease in the basic pH region. These results were discussed in terms of the effect of the short-range repulsion forces between the coating layer and the particle surface in aqueous suspensions. 相似文献
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Mitra Akhtari Zavareh Ahmed Aly Diaa Mohammed Sarhan Ramin Karimzadeh Ramesh Singh A./l.Kuldip Singh 《Ceramics International》2018,44(6):5967-5975
Corrosion is the deterioration of materials by chemical interaction with their environment. In the oil and gas industry, corrosion of the pipelines and other equipment is one of the leading causes of failure and the corrosion-related costs are very high. Hence, corrosion protection is an essential requirement. In this study, the objective is to analysis of the corrosion protection behavior of spray Alumina-Titania (Al2O3-TiO2) oxide ceramic coating on carbon steel pipes C45 using two different thermal spray coatings processes. These two different thermal spraying coating, High velocity oxy-fuel (HVOF) and plasma thermal spraying techniques can be used instead of extensive treatment by expensive chemical formation of coatings on pipelines and equipment to improve or restore a component's surface properties or dimensions and to protect them from corrosion. Molten or semi-molten ceramic composite powders are sprayed on the surface in order to produce a dense coating layer. FESEM of coated samples showed that a high temperature of plasma coating method end in melting the ceramic powders and creation of completely melted regions on the coated samples’ surface compared to HVOF coating techniques. Corrosion testing of coated samples in seawater (3.5% NaCl) was conducted within 30 days. Electrochemical impedance spectroscopy (EIS) as well as potentiodynamic polarization outcomes represented that the corrosion resistivity of plasma coating technique for this type of ceramic composite is better than HVOF coating technique. However, both types of coating techniques are protecting the substrate against seawater. 相似文献
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讨论了纳米TiO2的微观结构及其性能,对不同制备纳米TiO2的工艺路线进行了阐述和比较。同时对纳米 TiO2的表面处理技术和效果作了介绍。 相似文献