【作者】 陈洁；

【导师】 李廷举；

【作者基本信息】 大连理工大学 ， 材料加工工程， 2011， 硕士

【摘要】 随着人类社会的发展,铜的应用开发前景日益广阔。在传统的铜及铜合金材料体系的基础上,高性能铜材的开发研究已成为了现今铜材研究的主要方向。高纯铜(纯度在5N-7N)以其优异的导电、导热性、良好的延展性而广泛应用于半导体键合丝、高保真音响线缆、溅射靶材等制造领域。传统高纯铜的制备方法主要有电解法、区域熔炼、离子交换及真空精炼等,其中应用最为广泛的是电解法。然而电解法能耗较高、生产工艺复杂、质量不稳定。区域熔炼需要反复区熔,能耗高且难以去除固液平衡分配系数相差较小的杂质元素。阴离子交换法工艺复杂,质量不稳定且不利于环保。最新的国内外研究发现,高真空电子束可有效去除P、Ag、As、Se、Te等饱和蒸汽压高于铜的杂质元素,结合定向凝固技术可有效去除剩下的绝大部分杂质,从而获得高纯铜材。该技术工艺简单,不涉及多种复杂的化学反应,生产效率较高且利于环保。本论文以制备大尺寸高纯铜铸锭为目的,采用真空感应熔炼及电子束精炼结合定向凝固技术对4N电解铜进行除杂净化。成功制备F 67mm,长度大于90mm,纯度达到5N高纯铜铸锭。研究发现：真空熔炼可以有效去除铜中饱和蒸气压高的杂质；拉速为1mm/min的定向凝固过程中,由于铜基体对一些杂质元素具有较强的吸附作用,ko=0.72～1.3的杂质元素没有出现明显的偏聚效应。在真空度为30-90Pa、感应熔炼温度为1573K时保持精炼时间30min后总杂质含量由11ppmw降低至5.06ppmw,主要气体O,H元素的含量降低69.47%,H含量低于1ppmw。电子束池熔精炼能够有效去除大部分饱和蒸气压较高的杂质元素,其中Na, Mg, Al, P, Zn, Ga, Pd, Ag, In, W, U的去除率都达到60%以上。真空感应熔炼一次定向凝固铸锭经过两次池熔精炼后,铜中主要杂质元素总量由11ppmw降低至3.1ppmw,二次电子束池熔的除气及除杂效果没有一次池熔明显。电子束滴熔直接定向凝固实验中,杂质元素含量较原材料降低了28.2%。滴熔时纯铜液滴由于局部过热,反应速率较快,纯化材料和坩埚之间的反应及元素扩散成为了本实验的限制性因素。通过对比电子束池熔及滴熔精炼工艺,总结得到合理的提纯工艺路线是：真空感应熔炼定向凝固-电子束滴熔直接定向凝固。更多还原

【Abstract】 With social development, application of copper has broad prospects. High-purity copper (5N-7N purity) because of its excellent thermal conductivity, low impurity content, good ductility can be widely used in semiconductor, bonding wire, sputtering targets and other industry fields.Traditional methods to produce high purity copper conclude electrolysis, zone melting, ion exchange and vacuum refining. And electrolysis is the most widely used method but with some defects, such as high energy consumption, complex process and instable quality. Zone melting need repeated heating and it is difficult to remove the element which the value of ko is near 1. Anion exchange is complex, quality inconsistent and not environmentally friendly. The latest study have found that P, Ag, As, Se, Te which vapor pressure is higher than that of copper’s can be effectively removed by electron beam(EB) melting and most other impurities can be removed by directional solidification technique.In this paper, all the efforts are devoted to producing large-sized high purity copper.4N purity cathode copper was used as the start material, and F 67mm, lengths greater than 90mm, 5N high purity copper ingots have been prepared by vacuum melting and directional solidification.Impurities with high vapor pressure can be effectively removed by vacuum melting. Because of the strong affinity of Cu for some of the impurities, the segregation effect does occur when the ko value is in the range from 0.72 to 1.3. Vacuum 30～90Pa, induction melting temperature of 1573K, after 30min refining, the content of impurities decreased from 11ppmw to 5.06ppmw, and the main gas elements(O, H) decreased 69.47%, the content of hydrogen is lower than 1 ppmw.Impurities can be removed effective by EB pool melting, and the removal efficiency of Na, Mg, Al, P, Zn, Ga, Pd, Ag,In, W, U is up to 60% separately. The content of main impurities decreased from 1 lppmw to 3.1ppmw after vacuum induction melting directional solidification and two times of EB pool refining; the removal effeciency of gas and other impurities in the secondary EB pool melting was not significant.In the EB drip melting and directional solidification experiment, the content of impurities was 28.2% lower than that of the raw materials. EB drip melting experiments show that reaction between crucible and molten copper was the limiting factor. Using more high purity graphite crucible will be able to minimize melt contamination. Comparing the results of EB pool melting with EB drip melting, a reasonable purification process is the vacuum induction melting and directional solidification-electron beam drip melting and directional solidification.更多还原