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

金属颗粒的用途和特性是由其大小和形态决定的。因此，精确的粒度和形貌控制以及粉末生产的简单工艺为未来的新性能提供了先进的使用和改进。在本研究中，金属胺配合物和草酸盐通过热分解沉淀在溶液中的针状前体可以制备出镍、铜、钴等金属颗粒。溶液中形成的形态在热分解中保持不变。镍颗粒的平均长度为100微米，宽度为10纳米，在较高的热分解温度下呈链状。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以抑制金属颗粒的聚集，但金属颗粒的聚集倾向较小。通过氢氧化镍向草酸镍的转化，在无氨的溶液中得到了具有矩形平行六面体形状的单分散镍前驱体。将该工艺应用于铜颗粒的合成。通过控制溶液中离子类型和离子过饱和对沉淀反应的影响以及镍颗粒的合成，可以得到棒状和球形的铜颗粒。此外，采用多元醇法制备了纳米级铜颗粒。该方法由多元醇工艺中的两步还原路线组成。一是从铜离子还原为亚铜离子，再从亚铜还原为金属铜。得到了尺寸分布窄、抗氧化性能良好的80 nm铜纳米颗粒。这种两步还原法不仅强制断开成核和成核生长，而且削弱了常规的可喷发成核。PVP防止铜颗粒聚集和防止铜颗粒氧化是这一过程的两个主要作用

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