Black sintered body and method for producing the same
A sintered body includes a solid solution containing cobalt and iron, with the balance being zirconia. The total content of cobalt in terms of CoO and iron in terms of Fe 2 O 3 is more than 0.1 wt % and less than 3.0 wt %, and the proportion of cobalt regions larger than 5.5 μm 2 in an elemental map obtained using an electron probe microanalyzer is 25% or less.
1. A sintered body comprising a solid solution containing cobalt and iron, with the balance being zirconia, wherein a total content of cobalt in terms of CoO and iron in terms of Fe 2 O 3 is more than 0.1 wt % and less than 3.0 wt %, the content of chromium in terms of Cr 2 O 3 is less than 0.1 wt %, and a proportion of cobalt regions larger than 5.5 um 2 in an elemental map obtained using an electron probe microanalyzer is 25% or less.
2. The sintered body according to claim 1 , wherein a proportion of iron regions larger than 6.5 um 2 in the elemental map obtained using an electron probe microanalyzer is 30% or less.
3. The sintered body according to claim 1 , wherein a proportion of iron regions larger than 5.0 um 2 in the elemental map obtained using an electron probe microanalyzer is 50% or less.
4. The sintered body according to claim 1 , comprising aluminum oxide.
5. The sintered body according to claim 1 , wherein the zirconia contains at least one selected from the group consisting of yttria, calcia, magnesia, vanadia and titania.
6. The sintered body according to claim 1 , wherein the zirconia contains titania and yttria.
7. The sintered body according to claim 1 , wherein the zirconia contains titania in an amount of 1.0 mol % or more and 6.0 mol % or less and yttria in an amount of 2.0 mol % or more and 4.0 mol % or less.
8. The sintered body according to claim 1 , wherein the zirconia has a monoclinic fraction of 10% or less.
9. The sintered body according to claim 1 , wherein crystal particles of the zirconia have an average size of 3.0 μm or less.
10. A method for producing the sintered body according to claim 1 , comprising sintering, in a reducing atmosphere, a green body including a cobalt compound and an iron compound, with the balance being zirconia, wherein a total content of cobalt in terms of CoO and iron in terms of Fe 2 O 3 is more than 0.1 wt % and less than 3.0 wt %.
11. The production method according to claim 10 , wherein the reducing atmosphere is an atmosphere in which at least one of a reducing gas or a reducing heating material is used.
12. The production method according to claim 10 , wherein the sintering is pressure sintering.
13. The production method according to claim 10 , further comprising presintering the green body in a non-reducing atmosphere to obtain a presintered body.
14. The production method according to claim 10 , further comprising heat treating the sintered body in an oxidizing atmosphere at 650° C. or higher and 1100° C. or lower.