温度对分步还原法制备纳米银-铜包覆粉的影响

Effect of Temperature on the Preparation of Nano Silver Coated Copper Powder by Step-by-step Reduction Method

在硫酸铜和硝酸银溶液体系中,以葡萄糖、甲醛为还原剂,PVP为分散剂,采用分步化学还原法制备纳米银-铜包覆粉,重点研究了反应温度对制备过程及产品形貌的影响。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)及X射线衍射仪(XRD)对银-铜包覆粉的形貌、结构及相组成进行分析表征。结果表明,随着反应温度的升高,产物中银含量和产品粒度逐渐增大,而铜含量和颗粒团聚现象逐渐减少。当反应温度在70℃以下时,制备出的银-铜包覆粉为类球形;而当反应温度增至80℃时,所得到的是一种树枝状颗粒。当反应温度为70℃时,得到的是分散均匀、粒度为100 nm左右的银-铜包覆粉。反应温度的升高有助于体系中Cu纳米颗粒的形成,反应温度小于50℃时产物中夹杂有大量的Cu2O,反应温度大于60℃时可制备出银包覆层厚度为2~3 nm的纳米银-铜包覆粉。

In the copper sulfate and silver nitrate solution system,glucose,formaldehyde was used as the reducing agent and PVP was used as the dispersing agent.The nano-silver-coppercoated powder was prepared by step chemical reduction method.The effect of reaction temperature on the preparation process and product appearance was investigated.The appearance,structure and phase composition of silver coated copper powder were characterized by Scanning Electron Microscopy(SEM),Transmission Electron Microscopy(TEM)and X-Ray Diffraction(XRD).The results show that with the increase ofthe reaction temperature,the silver content and particle size of the product gradually increase,while the copper content and particle agglomeration gradually decrease.When the reaction temperature is below 70℃,the prepared silver coated copper powder is spherical-like;and when the reaction temperature increases to 80℃,a dendritic particle is obtained.When the reaction temperature is 70℃,a silver copper coated powder with uniform dispersion and particle size of about 100 nm is obtained.The increase of reaction temperature contributes to the formation of Cu nanoparticles in the system.The products contain a large amount of Cu 2 O at a low temperature(<50℃),and the silver-copper coated powder is prepared at a higher temperature(>60℃),and its thickness is about 2~3 nm.