Synthesis of Needle-like Metal Fine Particles by Hydroprocess and Size Control

金属颗粒的大小和形态决定了金属颗粒的用途和特性。因此，精确控制粉末的大小和形貌，以及易于生产的粉末生产工艺，将为未来的新性能提供先进的使用和改进。在本研究中，金属氨络合物和草酸盐热分解沉淀在溶液中的针状前驱体，可以制备出镍、铜、钴等金属颗粒。溶液中形成的形貌在热分解过程中保持不变。镍颗粒平均长度为100微米，宽度为10纳米，在较高的热分解温度下呈链状分布。虽然金属颗粒较小时容易相互聚集，但在制备前驱体的沉淀过程中，在溶液中加入聚合物分散剂可抑制团聚。…法制备了具有矩形六面体形状的单分散镍前驱体在不含氨的溶液中，氢氧化镍转化为草酸镍，并应用于铜粉的合成。通过控制溶液中的离子类型和离子过饱和度，对溶液中的沉淀反应和镍粉的合成进行控制，可以得到棒状和球状的铜粉。此外，还采用多元醇法合成了纳米铜粉。该方法由多元醇法两步还原路线组成。一种是由铜离子还原为铜离子，再由铜离子还原为金属铜。得到了粒径分布较窄、抗氧化性能较好的80 nm铜纳米粒子。这种两步还原的方法不仅强制切断了形核和形核生长之间的联系，而且还削弱了传统的可喷发形核。在这一过程中，PVP主要起到了防止铜粉团聚和防止铜粉氧化的作用

The usage and characteristics of metallic particles are determined by the size and morphology. Therefore, accurate control of size and morphology and easy process for powder production gives advanced usage and improvement of new properties in the future. In this investigation, metallic particles such as nickel, copper, cobalt can be fabricated from thermal decomposition of the needle-like precursors precipitated in the solution with metal ammine complexes and oxalate salts. The morphology formed in the solution was maintained in thermal decomposition. Nickel particles were 100 micrometer in average length and several 10 nanometer in width, which changed to chain-like shape in higher thermal decomposition temperature. Though metallic particles tended to aggregate each other as smaller, aggregation was inhibited by adding polymer dispersant in the solution in precipitation process for precursors fabrication. Monodispersed Ni precursors with rectangular parallelepiped in shape were obtain … More ed in the solution without ammonia thorough the transformation of nickel hydroxide to nickel oxalate.This process was applied to copper particle synthesis. Copper particles with rod type and sphere type can be obtained by controlling ion type and ion oversaturation to the precipitation reaction in the solution as well as the synthesis of nickel particles.In addition, copper particles in nano size were synthesized by means of polyol process. This method consists of two-step reduction route in polyol process. One is reduction from cupric ion to cuprous ion and following from cuprous to metallic copper. We obtained 80 nm copper nano-particles with narrow size distribution and with satisfied anti-oxidation property. This two-step reduction method compulsively not only disconnects nucleation and nucleation growth, but also weakens conventional eruptible nucleation. PVP preventing the copper particles from aggregation and preventing the copper particles form oxidation are two main roles in this process Less