Cobalt-Free NTC Ceramic and Method for Producing a Cobalt-Free NTC Ceramic
AssigneeEpcos AG
InventorAdalbert Feltz
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Abstract
The invention relates to a cobalt-free NTC ceramic having the composition Nia′Cub′Coc′MndO4 where 0.09<a′<0.6, 0.02<b′<0.65, 0.12<c′<0.58 and 1.6<d′<2.1. The invention further relates to a method for producing a cobalt-free NTC ceramic, the composition of which is derived from a cobalt-containing NTC ceramic of general formula NiaCubCocMndO4 where 0.09<a<0.6, 0.02<b<0.65, 0.12<c<0.58 and 1.6<d<2.1, wherein Co is replaced by Zn.
Claims20
A cobalt-free ceramic with a negative temperature coefficient of electrical resistance (NTC ceramic), having the general formula Nia′Cub′Znc′Mnd′O4 with 0.09<a′<0.6, 0.02<b′<0.65, 0.12<c′<0.58 and 1.6<d′<2.1.
A method for producing a cobalt-free NTC ceramic, the composition of which is derived from a cobalt-containing NTC ceramic having the general formula NiaCubCocMndO4 with 0.09<a<0.6, 0.02<b<0.65, 0.12<c<0.58 and 1.6<d<2.1, Co being replaced by Zn, comprising the method steps:
- A) formal decomposition of NiaCubCocMndO4 into spinel components, which respectively contain at least one oxide of Ni, Cu, Co or Mn,
- B) formal replacement at least of the cobalt-containing spinel components by cobalt-free spinel components,
- C) formal composition of the at least partially replaced spinel components to form an intermediate stage having the composition NiαCuβZnγMn67O4 with 0.09<α<0.6, 0.02<β<0.65, 0.12<γ<0.58 and 1.6<δ<2.1,
- D) adaptation of α, β, γ and δ in order to obtain a composition Nia′Cub′Znc′Mnd′O4 with 0.09<a′<0.6, 0.02<b′<0.65, 0.12<c′<0.58 and 1.6<d′<2.1, wherein the adaptation is carried out while assimilating the electrical properties of the cobalt-free NTC ceramic to the electrical properties of the cobalt-containing NTC ceramic,
- E) production of a ceramic having the composition Nia′Cub′Znc′Mnd′O4 from starting substances.
Dependencies are inferred from the claim text.