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1.
铝电解过程对电解铝液的净化作用探讨   总被引:2,自引:0,他引:2  
贺永东 《轻金属》2007,32(9):32-36
本文对比分析了采用长流程、短流程工艺熔铸铝合金过程中,氢和氧化铝夹杂的形成过程。分析了铝电解工艺过程对电解铝液的自净化作用。电解铝的工作介质为冰晶石熔体,对氧化铝有良好的溶解性能,通过溶解电解液-铝液界面上的氧化铝达到脱氢除杂的效果。电解铝液中存在的微量稀土具有固氢排杂的作用。现代大型铝电解槽电流强度达到350kA,存在于铝液中的不导电、不被铝液润湿的氧化铝夹杂,在强烈电磁场的耦合作用下聚集沉降在电解槽的边部、角部或铝液漩涡的交界处。  相似文献   

2.
纯铝与过滤材料和夹杂物之间的润湿性是影响铝的过滤性能的重要因素。在10-8bar真空条件下于1000~1300°C,研究液态铝与氧化铝、SiC和石墨之间的润湿角。为了描述铝的过滤和浇铸等在低温条件下铝与陶瓷的润湿行为,使用半经验模型进行研究。计算出的700°C的纯铝与氧化铝的润湿角为97°,与玻璃体石墨的为92°,与单晶和多晶石墨的为126°,与单晶的为SiC79°。结果表明:在浇铸温度下铝不能润湿氧化铝和石墨(或者Al4C3),但可以润湿SiC。因此,为了让铝能够浸润过滤材料,在铝过滤时需要施加一个压力差作为推动力。提高温度也可以改善铝与陶瓷间的润湿性。  相似文献   

3.
廖贤安  胡鹏飞 《轻金属》1989,(12):35-35,39
采用X射线透射摄影技术,测定了冰晶石-氯化铝熔体、铝和电极三相体素中铝与几种阴板材料的润湿角。铝在石墨和碳块上的润湿角为170~180°,铝在含TiB_2的涂层上的润湿角为51~79°.铝在热压TiB_2陶瓷块上的润湿角为0~46°.电极阴极极化与否和电解质的组成对润湿角无显著影响。  相似文献   

4.
用X射线座滴照像法测量了铝液-氟化物熔盐间的界面张力。采用曲线拟合液滴轮廓坐标的计算机程序处理座滴图像。用逐步回归分析方法获得了计算熔盐密度值的回归方程。讨论了熔盐中NaF/AlF_3分子比,Li_2CO_3和稀土氧化物含量对熔盐-铝液间界面张力的影响。测量了铝液在熔盐中对石墨、工业碳块以及TiB_2涂层的润湿角。  相似文献   

5.
戴斌煜 《铸造技术》2007,28(3):399-401
采用消失模铸造工艺制备Gr/Al复合材料,对该复合材料进行了磨损性能试验。通过对石墨颗粒进行活化或镀铜处理,并加入活性元素镁,改善了铝液与石墨之间的浸润性,提高了石墨收得率。结果表明,该工艺所制得的复合材料中石墨分布均匀、界面结合较紧密。最后对该复合材料的成形机理进行了探讨。  相似文献   

6.
铝液从熔化到浇注过程的质量变化及分析   总被引:3,自引:0,他引:3  
提出了从熔化后到浇注过程铝液的质量变化,阐述了不同铝液精炼工艺对铝液品质的影响,以及铝液精炼工艺与变质工艺的相互影响;采用密度测试法对从熔化到浇注过程的铝液精炼质量进行监控,对铝液精炼工艺的试验结果进行分析.  相似文献   

7.
铸造铝—石墨复合材料   总被引:1,自引:1,他引:0  
本文主要介绍作者提出的石墨不镀层加入铝液制造铝——石墨复合材料的新的旋涡法工艺,并对这种材料在挤压铸造与重力铸造条件下的机械、物理性能作了测定。指出铝——石墨复合材料具有优越的耐磨性、抗擦伤性和吸震性,适合于制造活塞等耐磨机件。  相似文献   

8.
采用座滴法研究石墨表面沉积钛薄膜对熔融铝与石墨在真空条件下润湿性的影响。结果表明,温度提高,加快了界面反应,石墨表面沉积的膜变厚,最终接触角变小,润湿效果变好。  相似文献   

9.
镁对铝与粉煤灰润湿性的影响   总被引:2,自引:0,他引:2  
用改进的座滴法测量了铝合金在粉煤灰上的润湿角.在铝中添加Mg能减小铝对粉煤灰的润湿角,由于Mg能在液滴表面挥发,破坏铝滴表面新产生的氧化铝,从而改善润湿性.粉煤灰中的SiO2、Fe2O3与铝发生反应,促进铝合金与基片的润湿,但铝滴表面Mg的挥发变慢,导致其破坏铝滴表面氧化铝的能力逐渐变弱,表层氧化铝的生长速度变快,同时SiO2、Fe2O3与铝反应减弱,反应性润湿影响变小,非反应性润湿在润湿过程中所起作用变大.  相似文献   

10.
ZnO-Al_2O_3-B_2O_3-SiO_2系微晶玻璃与可伐合金的润湿性能   总被引:1,自引:1,他引:0  
研制了一种新型的与可伐熔封的ZnO-Al_2O_3-B_2O_3-SiO_2系微晶玻璃,研究了不同工艺条件下微晶玻璃与可伐合金间的润湿角大小,结果表明,熔封气氛和熔封温度对润湿性能影响很大,熔封时间影响最小.采用最佳的工艺条件,其润湿性能与现有的其它玻璃润湿性能相似.同时发现玻璃与可伐合金间的润湿角保持在10°~30°之间能得到质量良好的熔封产品.在基本不改变传统工艺制度的条件下,可完成锌铝硼硅系微晶玻璃与可伐合金的熔封,即利用排蜡过程同时完成微晶玻璃的形核,熔封后在稍低温度保温或减慢冷却速度可以完成微晶玻璃的结晶过程.锌铝硼硅系微晶玻璃与预氧化可伐合金的封接依靠玻璃中的SiO_2与FeO或Fe_3O4发生界面反应形成牢固的结合.  相似文献   

11.
The intrinsic contact angle between liquid metal and a solid substrate is important for interpreting the contact interaction between them. However, the apparent contact angle revealed in a wetting test does not always coincide with the intrinsic angle. In this study, the intrinsic contact angle of liquid silver on monocrystalline and polycrytalline graphite substrates was investigated by means of a sessile drop method under a 10%H2−Ar atmosphere at 1273 K. The intrinsic contact angles were estimated to be 124° for the monocrystalline (C surface) and 127° for the polycrystalline.  相似文献   

12.
Abstract

The effects of Al and silicon additions to Cu based brazing alloy and the surface free silicon on siliconised graphite substrate on the wetting behaviour of the siliconised graphite by Cu–Al–Si–Ti alloys were investigated using the sessile drop technique at 1100°C. The contact angles were measured and the interfacial reactions were analysed. It was shown that surface free Si on siliconised graphite had a great positive effect on the contact angle. Furthermore, interfacial reactions could be controlled by adjusting the contents of Si and Al in brazing alloys.  相似文献   

13.
The present investigation aimed to evaluate the influence of zinc bath metallurgy on the hotdip galvanizing of a high-manganese-alloyed steel (commercial grade X-IP 1000). Wetting force and contact angle measurements were carried out by the Wilhelmy plate methodology to assess zinc bath compositions. The Wilhelmy plate methodology was particularly suitable for both quantifying liquid zinc wetting and producing coated samples to be characterized. The aluminium content of the zinc bath varied between 0.05 and 1.10 wt % and manganese as well as silicon was additionally added to the bath composition. Best wetting occurred with aluminium contents which are typical for industrial galvanizing baths (0.12-0.22 wt %). But zinc wetting and wetting reactivity decreased with increasing aluminium content > 0.30 wt %. Hence, aluminothermic MnO reduction seems to be ineffective in the present case. Wetting results might be further improved by adding manganese or silicon to the zinc bath due to an improved wetting reaction. However, the formation of additional phases in the coating has to be considered with regard to technical use.  相似文献   

14.
The wetting behavior of molten pure Mg droplets on pure Ti substrate, a crucial phenomenon in the design of Mg matrix composites reinforced with Ti particles, was investigated by the sessile drop method. The contact angle was measured in high-purity argon (99.999%) at 1073 K. In particular, the effects of two important parameters on the contact angle were evaluated: Mg evaporation during the wetting test; and surface oxide film of the substrate. The calculation method to estimate the modified contact angle involved taking the morphological changes of the droplet outline due to the evaporation into consideration. By changing the thickness of the surface oxide films on the Ti substrate, it was possible to examine the wettability and the chemical reactions at the interface between the solidified Mg drop and the substrate were investigated by scanning electron microscopy–energy dispersive X-ray spectrometry analysis. At the initial wetting stage, a large contact angle with 95–110° was obtained, which depended on the reduction of TiO2 surface films by Mg droplets. When the molten Mg contacts an area of pure Ti after reduction, the contact angle suddenly decreased. The equilibrium value at the stable state strongly depended on the surface roughness of the Ti plate.  相似文献   

15.
Wetting of Au and Ag particles on monocrystalline graphite substrates   总被引:1,自引:0,他引:1  
1. Introduction Carbon is widely used in areas such as the proc- essing of graphite-metal compacts, brazing of graph- itic materials and carbon nanotubes [1]. The most common carbon material is graphite. Recently, monocrystalline graphite is used as substrates for the fabrication and observation of metallic nanoparticles [2-4]. With decreasing particle size, the effects of the surface and substrate on the physical and chemical stabilities of the particles cannot be ignored due to the large sur…  相似文献   

16.
作为渗透检测中的润湿现象有三种方式:即粘湿、浸湿和铺展。若渗透液在固体受检试件表面上的接触角θ≤180°,则可发生粘湿;若接触角θ≤90°,则可发生浸湿;若接触角θ≈0°,则可发生铺展。凡能铺展者,必要浸湿,更能沾湿。渗透检测要求铺展。接触角臼的大小是由在气、液、固三种界面张力的大小所决定的。从接触角口数值大小可看出液体对固体润湿的程度。这些讨论有助于对渗透检测中实际问题的认识。  相似文献   

17.
The role played by interfacial reactions on pressure infiltration of ceramic preforms by liquid metals is still controversial. Experimental results for pressure infiltration of packed SiC particulates by pure silver with dissolved oxygen in a concentration near saturation are presented. In this system, SiC reacts with the large amount of oxygen which dissolves liquid silver. The results show that the threshold pressure for initiation of infiltration is higher than in SiC/aluminum, and, thus, do not reproduce the large drop in the threshold pressure found when packed alumina particles are infiltrated with silver instead of aluminum. On the other hand, the rate at which the infiltrated height increases as a function of the pressure drop in the liquid metal, is similar to that observed in alumina/silver. These results can be understood in terms of low wetting at the silver/SiC interface, which can be a consequence of a higher contact angle and a reduction in the contact area promoted by the gas evolved in the oxidation of SiC (mainly CO2 as indicated by mass spectrometry). This indicates that reactivity at the interface should not always be associated with an improvement in the wetting performance.  相似文献   

18.
本文使用静滴法研究了不同Mg含量(3.2, 4.5, 6.5, 8.5, 10, 13, 17 wt.% Mg)的Al-Mg合金在M40石墨纤维网上的润湿行为,重点讨论了Mg元素含量对润湿性及铺展速率的影响。 随着Al-Mg合金中的Mg含量从3.2 wt.%增加至17 wt.%,初始润湿角从115o降低到88.5o,而最终润湿角则由 96.7o降低到71o。由于M40石墨纤维的表面组织性质与普通石墨有较大的区别,因此与高密度碳平板相比,Al-Mg合金在石墨纤维网上的初始润湿角更小。而润湿角随Mg含量的增加而减小主要是源于Mg含量的增加可以显著降低Al-Mg合金的表面张力。基于Dezellus方程,进一步计算了Al-Mg合金在石墨纤维网上的铺展速率,计算结果与实验结果基本吻合。基于Miedema模型计算得到的铺展速率系数k也与实验结果基本吻合,此结果证明了Miedema模型在铺展速率计算方面应用的合理性。计算与实验结果均表明Mg元素含量的增加虽然可以显著降低润湿角,但对铺展速率影响不大。  相似文献   

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