RESUMO
Sintering behavior of copper nanoparticles with a protective layer of gelatin synthesized by wet-chemical process with an average diameter of 45 nm has been observed using in-situ transmission electron microscopy (TEM). Copper nanoparticles were sublimated without sintering at about 925 degrees C at 2.0 x 10(-)(5) Pa, and carbonized gelatin remained and retained the shape of the initial layer of nanoparticles. Copper nanoparticles were sintered without sublimation at about 250 degrees C with between 1.0 x 10(-)(4) and 6.0 x 10(-)(4) Pa of oxygen gas flow. It was found that the surface of the sintered copper was covered by a gelatin layer.
RESUMO
Size-controlled oxidation-resistant copper fine particles were prepared from insoluble CuO micron-sized particles. The particle sizes were quite uniform and could be varied only by the concentration of the complex reagent from 45 to 175 nm. No template material was needed for size control. Gelatin was selected as the protective polymer. Addition of protease after formation of copper fine particles decomposed preferentially loop and tail parts of gelatin. The remaining nanoskin gelatin layer, covered on the particle surface, prevents oxidation of copper.
Assuntos
Biopolímeros/química , Cobre/química , Nanoestruturas , Microscopia Eletrônica de Transmissão , Oxirredução , Tamanho da PartículaRESUMO
Well size-controlled copper fine particles (diameter: 100-300 nm) were used as the inner electrode material of multilayered ceramic capacitors (MLCCs). The particles were dispersed in terpineol to form a printing paste with 50 wt% copper particles. The MLCC precursor modules prepared by the layer-by-layer printing of copper and BaTiO(3) particles were cosintered. Detailed observation of the particles, paste, and MLCCs before and after sintering was carried out by electron microscopy. The sintering temperature of Cu-MLCC was as low as 960 °C. The permittivity of these MLCCs was successfully measured with the copper inner layers.
