| 2. | At the beginning of the reduction , the spherical ni powders precipitated at the tip of the precursor where specific surface energy is higher , then more and more ni powders appeared at the edges and the surface of the precursor ; finally the spherical ultrafine ni powders take the place of the whole precursor 在还原过程中,超细镍粉首先从冻干前驱体的尖端等比表面能较大的地方析出;随后前驱体的棱和表面逐渐析出大量的超细镍粉;最后镍粉颗粒替代整个前驱体,得到球状超细镍粉。 |