亜鉛滓を用いたZn-Mn-Al-O系スピネル固溶体の作製とNTC特性

概要

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Oxide spinels containing Zn, Mn and Al were synthesized from powder mixtures of Al (OH)_3 and IZC (Itomuka zinc calcine), the latter of which is derived from the waste of dead batteries and consists of ZnO and MnO. Heating of the powders with different Al_2O_3/ (ZnO + MnO) molar ratio (A/I value) ranging from 0.44 to 0.88 resulted in the formation of a single phase of spinel solid solution above 1000℃. The lattice parameter of the spinel s.s. with different cation ratios decreased almost linearly with increasing Al_2O_3 content. The chemical formulae of the solid solutions were estimated to be Zn (II) _<0.74>Mn (II) _<0.26>Mn (III) _<0.60>Al (III)_<1.40>O_4 and Zn (II) _<0.50>Mn (II)_<0.50>Mn (III) _<0.09>Al (III)_<1.91>O_4 for the samples with A/I= 0.44 and A/I= 0.88, respectively. Sintering of spinel powders calcined at 1100℃ was enhanced at 1450℃ to produce densified spinel ceramics with 90-93% of theoretical density. The addition of 4 mass%B_2O_3 or 4 mass%Bi_2O_3 to synthesized powders caused the sintering temperature at which highly densified bodies were obtainable to be substantially lowered down to 1200℃, without any appreciable effect on the electrical properties of the sintered samples. The spinel s.s. ceramics having a composition of A/I= 0.66 showed a negative linear temperature dependence of electrical resistivity with a thermistor constant (B) of 3240-3390 K.
社団法人日本セラミックス協会の論文
2002-07-01