The development of a simple method that perfectly controls the oxidation and aggregation of metallic particles has been performed. In the present work, metallic nickel (Ni) particles were used as a control, and silica-coating of them was performed to control oxidation and aggregation of them. Metallic Ni particles with a particle size of 924.1 ± 315.7 nm were synthesized in water and exposed to air. Nickel(II) acetate tetrahydrate, hydrazine, and poly(sodium 4-styrenesulfonate) were used as the Ni source, reducing reagent, and stabilizer, respectively. Silica-coating of the metallic Ni particles was performed by adding tetraethylorthosilicate/(3-aminopropyl)triethoxysilane/ethanol solution to the metallic Ni particle colloid solution (Ni/SiO₂). The uncoated metallic Ni particles and metallic Ni in the Ni/SiO₂ particles began to be oxidized while annealing in air to form NiO at 400 and 500 °C, respectively; the oxidation of metallic Ni particles was controlled by the silica coating. The Ni/SiO₂ particles prepared and annealed at 100–300 °C showed soft magnetic behavior, and the saturation magnetization of g-Ni was almost comparable to that of bulk metallic Ni. In addition, the Ni/SiO₂ particles annealed even at 500 °C still had soft magnetic behavior, which also supported that the oxidation of metallic Ni particles was successfully controlled by the silica coating.

已经开发出一种可以完美控制金属颗粒氧化和聚集的简单方法。在目前的工作中，金属镍 (Ni) 颗粒用作对照，并对它们进行二氧化硅涂层以控制它们的氧化和聚集。粒径为 924.1 ± 315.7 nm 的金属镍颗粒在水中合成并暴露于空气中。四水醋酸镍 (II)、肼和聚（4-苯乙烯磺酸钠）分别用作 Ni 源、还原剂和稳定剂。通过向金属Ni颗粒胶体溶液(Ni/SiO ₂ )中加入原硅酸四乙酯/(3-氨基丙基)三乙氧基硅烷/乙醇溶液来进行金属Ni颗粒的二氧化硅包覆。Ni/SiO 中未包覆的金属 Ni 颗粒和金属 Ni_2个颗粒在空气中退火时开始被氧化，分别在400和500℃下形成NiO；金属镍颗粒的氧化由二氧化硅涂层控制。制备并在 100-300 °C 下退火的 Ni/SiO ₂颗粒表现出软磁行为，g-Ni 的饱和磁化强度几乎与块状金属 Ni 的饱和磁化强度相当。此外，即使在 500 °C 下退火的 Ni/SiO ₂颗粒仍具有软磁行为，这也证明了二氧化硅涂层成功地控制了金属 Ni 颗粒的氧化。