低温焼成・無収縮Ni-Cu-Znフエライト材料 Non-Shrinkage Ni-Cu-Zn Ferrites sintered at low temperature
We have developed a Non-Shrinkage Ferrites "NSF" having near-net-shape by adding metallic Fe and sintered at high temperature (about 1200°C). In this work, we report low temperature (under the melting point of Ag, 960°C) sintered NSF. The control of the degree of NSF shrinkage is possible through utilizing both the expansion caused by the oxidation of metallic Fe and the complex chemical reaction allowed with NiO, ZnO, and CuO during sintering up to 920°C. In the case of low temperature sintering, high density NSF cannot be realized because non-uniform grain caused by the extreme oxidation of metallic Fe remains. It is found that addition of low-melting point oxides to the NSF permits effectively the NSF's microstructure to make uniform and compact. XRD and VSM show these NSF have the complete spinel crystal structure of ferrite. As a result, the shrinkage of low temperature sintered NSF is extremely small (-0.4%) and their magnetic characteristics are actually identical with those of conventional low temperature sintered ferrites.
粉体および粉末冶金 46(1), 98-102, 1999-01-15
Japan Society of Powder and Powder Metallurgy