真空蒸发法制备超细铜粉新工艺的实验研究

发布时间：2018-02-04 17:21

本文关键词： 超细铜粉真空蒸发冷凝制备　出处：《昆明理工大学》2011年硕士论文　论文类型：学位论文

【摘要】：超细铜粉由于具有一系列与常规材料不同的物理、化学特性,被广泛用于粉末冶金、催化、医药等领域,随着社会经济的发展和科学技术的进步,对超细铜粉的数量和质量的要求越来越高。本研究在分析各种超细铜粉的制备方法及工艺、铜粉制备设备的研究基础上,提出了真空蒸发冷凝制备超细铜粉的新思路。通过激光粒度分析仪(LS)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、辉光放电质谱仪(GDMS)、差示扫描量热分析仪(DSC)等手段对超细铜粉粒度、形貌、物相、纯度、熔点进行表征,所获得超细球形铜粉平均粒径小于2μm,超细片状铜粉平均粒径为10-30μm、厚1～2μm,粒径分布较窄且均匀可控,分散性好,纯度高。本研究自行设计了两类新型冷凝器来收集超细铜粉,一类是三层石墨冷凝器,另一类是水冷钢板。论文考察了两类冷凝器的主要影响因素,探讨了真空蒸发冷凝制备超细铜粉的机理,系统研究了工艺参数对金属铜的蒸发速率、超细铜粉的形貌、平均粒度、粒度分布、产率等的影响规律,得到如下结论： 1.金属铜的蒸发速率和超细铜粉产率随蒸发温度(T)的升高、真空度(P)的增大、铜金属熔体蒸发面积(S)的增大、坩埚内铜液面高度(H)的增大而增大。 2.通过单因素条件试验,分别得到了两类冷凝器下的优化工艺条件。研究发现蒸发温度、真空度、保温时间对超细铜粉的形貌、平均粒度和粒度分布有相似的影响,且为主要影响因素。随蒸发温度升高、真空度降低、保温时间增大,超细铜粉的平均粒度增大,粒度分布变宽。对于三层石墨冷凝器,最佳工艺条件为：蒸发温度为1673K,压力为10Pa,保温时间为70min,最佳冷凝区域为第二层；对于水冷钢板,最佳工艺条件为：蒸发温度为1673K,压力为10Pa,保温时间为70min,冷却水流量为160L/h,冷凝高度为7cm。 3.在不同的工艺条件下所制备的超细铜粉的形貌差别很大。小颗粒铜粉一般呈现球形或类球形；大颗粒铜粉往往呈现表面平整的片状。通过调节真空蒸发冷凝制备超细铜粉工艺参数可以控制超细铜粉的平均粒度、粒度分布和形貌。
[Abstract]:Ultrafine copper powder has been widely used in powder metallurgy, catalysis, medicine and other fields because of a series of physical and chemical properties different from conventional materials. With the development of social economy and science and technology, the ultrafine copper powder has been widely used in the fields of powder metallurgy, catalysis, medicine and so on. The requirement of quantity and quality of ultrafine copper powder is higher and higher. This research is based on the analysis of the preparation method and technology of various ultrafine copper powder and the research of copper powder preparation equipment. A new idea of preparing ultrafine copper powder by vacuum evaporation condensation was put forward. By means of laser particle size analyzer, scanning electron microscope (SEM), and transmission electron microscope (TEM), the X-ray diffractometer (XRD) was used. The particle size, morphology, phase, purity and melting point of ultrafine copper powder were characterized by GDMS and DSC. The average particle size of ultrafine spherical copper powder is less than 2 渭 m, the average particle size of ultrafine flake copper powder is 10-30 渭 m, the thickness of copper powder is 1 ~ 2 渭 m, the particle size distribution is narrow, uniform and controllable, the dispersion is good, and the purity is high. In this study, two new types of condensers were designed to collect ultrafine copper powder, one is three-layer graphite condenser and the other is water-cooled steel plate. The mechanism of preparing ultrafine copper powder by vacuum evaporation condensation was discussed. The influence of process parameters on the evaporation rate, morphology, average particle size, particle size distribution and yield of metal copper powder were systematically studied. The following conclusions have been drawn: 1. The evaporation rate of copper and the yield of ultrafine copper powder increase with the increase of evaporation temperature (T), the vacuum degree (P), and the evaporation area (S) of copper melt. The increase of copper surface height in crucible increases. 2. Two kinds of condensers were optimized by single factor experiments. The morphology of ultrafine copper powder was investigated by evaporation temperature, vacuum and holding time. With the increase of evaporation temperature, the vacuum degree decreases, the holding time increases, and the average particle size of ultrafine copper powder increases. For the three-layer graphite condenser, the optimum process conditions are as follows: evaporation temperature is 1673K, pressure is 10Pa, holding time is 70min, and the best condensing area is the second layer. For water-cooled steel plate, the optimum technological conditions are as follows: evaporation temperature is 1673K, pressure is 10Pa, holding time is 70min, cooling water flow rate is 160L / h, condensation height is 7cm. 3. The morphology of ultrafine copper powder prepared under different technological conditions is very different. The average particle size, particle size distribution and morphology of ultrafine copper powder can be controlled by adjusting the technological parameters of vacuum evaporation condensation to prepare ultrafine copper powder.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TF123.23

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