Modeling a linear electric molten zone in a silicon ribbon

The linear electric molten zone produced by passing an electric current in a silicon ribbon may be used to create a floating molten zone specially suited for a recrystallization process. A one‐dimensional heat transfer numerical model of a linear electric molten zone is developed. Simulation results show the electric current concentration mechanism, and describe the effect of parameters such as the auxiliary radiative input power, or the ribbon thermal conditioning and geometry on the temperature profile and the molten zone width. It is shown that producing a linear molten zone electrically, is about half as energy intensive as if this were done solely by radiative heating. Copyright © 2009 John Wiley & Sons, Ltd.     

铝硅酸钙熔体中氧原子的配位性质及动力学

采用分子动力学模拟研究了xAl2O3(1-x)(CaO·SiO2)系熔体中氧原子的配位及其动力学性质.实验发现:以Al为中心的次近邻的配位数总和大约为8,说明存在大量的三配位氧(triclusteroxygen,Ot).在对平衡构像的分析过程中发现主要存在2种形式的三配位氧:Ot(Al,Al,Si)和Ot(Al,Al,Al),但没有发现Ot(AL, Si,Si)和Ot(Si,Si,Si).另外,对存在的三配位氧的进一步分析表明这2种三配位氧还存在共棱和不共棱的精细结构.共棱现象只发生在AlO4四面体之间;而SiO4四面体之间,或者SiO4四面体和AlO4四面体之间不存在共棱现象.在此基础上,还对氧的均方位移及速度自相关函数等动力学性质进行了分析,发现三配位氧的增加明显降低氧原子的活动能力.     

Corrosion Resistance of High-Alumina Graphite Based Refractories to the Smelting Reduction Melts

1 Introduction The corrosion resistance of the refractories is one of the imperative problems for the development of smel- ting reduction with iron bath[1 ~4]. The Al2O3-C based refractories have been widely and successfully used in the metallurgy industr…     

高聚物熔体挤出不稳定流动的研究进展

对近年来国内外关于熔体挤出不稳定流动现象的研究进展进行了介绍。阐述了关于形成鲨鱼皮和压力振荡及其他挤出不稳定流动的相关机理，并总结了抑制挤出不稳定现象所采取的措施。     

熔体搅拌Al－12．0％Si合金的组织细化

通过研究不同熔体交变搅拌工艺对Ａｌ－１２．０％Ｓｉ合金微观组织的影响发现，从高于熔点某温度开始对熔体的持续搅拌，不仅可以球化、细化合金的初生相，细化晶粒，而且可以有效地细化共晶硅。这归因于熔体搅拌引起的熔体结构及特性的变化。     

HR-2不锈钢表面渗Al涂层的制备

为避免制备温度过高引起基体性能退化,采用了室温熔盐电镀与热处理复合技术在HR-2不锈钢卜进行了渗Al涂层制备研究,并对涂层的形貌、结构和成分进行了表征.结果表明,利用该技术制备渗Al涂层是可行的;经500℃和700℃两种温度下热处理,成功制得成分渐变,冶金结合且无缝隙和裂纹的10-15 μm厚渗Al涂层.经700℃下2 h热处理后,渗Al涂层与基体无明显界面,依次由(Fe,Cr,Mn,Ni)2Al5,(Fe,Cr,Mn,Ni)Al和(Fe,Cr,Mn,Ni)3Al3层组成;与700℃热处理后不同,经500℃下10 h热处理后,渗Al涂层与基体间界面明显,由内外两层组成.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

一个值得电解铝厂重视和采用的冰晶石替代方法

本文从冰晶石-氧化铝熔盐电解法(即霍尔-埃鲁法)的理论基础入手,简要分析了工业铝电解质的组成及过量电解质的产生原因,建议国内铝厂重视过量电解质的循环利用,逐步减少并替代冰晶石的使用,参与全球范围的过量电解质交易,有效盘活资源,降低新电解槽启动成本和生产成本。     

高铬铁基熔体中磷和铬的热力学性质的研究

通过Fe－Cr－C系中碳的溶解平衡实验和铝、磷在BaO－BaCl2渣和Fe－Cr－C—P系间的分配平衡实验，心别测定11723K时三元系中碳的溶解度和个街时铬、磷在渣余间的浓度关系根据实验结果，应用热力学理论求得了和，并提出厂适用于高铬含碳铁基熔体中格和磷的活度系数计算式     

单组分聚氨酯胶粘剂发展简介

单组分聚氨酯胶粘剂因无计量失误之虞、使用简便,发展很快。简要介绍了其分类、性能及用途。其中以湿固化型为主流,反应性热熔型和射线固化型发展最快。