Study on preparation process of ultrafine copper powders for MLCC electrode

The ultrafine copper powders were prepared by NaOH precipitation-glucose pre-reduction and hydrate hydrazine reduction process with CuSO4 as material. The ultrafine copper powders are spherical, uniform and well-dispersed, which can be used for MLCC electrode. The effects of glucose pre-reduction, hydrate hydrazine reduction process and additive agents of PVP and NH4Cl on copper powders have been studied. The results show that glucose pre-reduction and adding hydrate hydrazine in twice can make copper particles grow uniformly. PVP is beneficial to the uniformity and sphericity of copper powder particles, the molar ratio n(Cu):n(NH4Cl) has remarkable influence on the particle size and shape. With the increasing of NH4Cl, the copper particles become smaller, and when the molar ratio of n(Cu):n(NH4Cl) is 1:1, shape of copper particles from spheroid turns into polyhedron.