A ferrite sintered magnet comprising an M type Sr ferrite having a hexagonal structure as a main phase, wherein the ferrite sintered magnet comprises La and Co, a content of B is 0.005 to 0.9% by mass in terms of B.sub.2O.sub.3, a content of Zn is 0.01 to 1.2% by mass in terms of ZnO, and the ferrite sintered magnet satisfies [La]/[Zn]≤0.79 and [Co]/[Zn]≤0.67 when an atomic concentration of La is represented by [La], an atomic concentration of Co is represented by [Co], and an atomic concentration of Zn is represented by [Zn].

In an embodiment a ceramic material includes ZnO as main constituent, Y as a first additive, second additives including at least one compound containing a metal element, wherein the metal element is selected from the group consisting of Bi, Cr, Co, Mn, Ni and Sb, Si.sup.4+ as a first dopant and second dopants having at least one compound containing a metal cation from Al.sup.3+, B.sup.3+, or Ba.sup.2+, wherein a corresponds to a molar proportion of Bi calculated as Bi.sub.2O.sub.3, b corresponds to a molar proportion of Y calculated as Y.sub.2O.sub.3, c corresponds to a molar proportion of Al calculated as Al.sub.2O.sub.3, d corresponds to a molar proportion of Ba calculated as BaO, e corresponds to a molar proportion of B calculated as B.sub.2O.sub.3, f corresponds to a molar proportion of Si calculated as SiO.sub.2, g corresponds to a molar proportion of Ni calculated as NiO, h corresponds to a molar proportion of Co calculated as Co.sub.3O.sub.4, i corresponds to a molar proportion of Cr calculated as Cr.sub.2O.sub.3, j corresponds to a molar proportion of Sb calculated as Sb.sub.2O.sub.3, and k corresponds to a molar proportion of Mn calculated as Mn.sub.3O.sub.4.

To provide a sintered body with improved impact resistance due to impact absorption through plastic deformation before brittle fracture for an impact exceeding the fracture resistance of the sintered body, and/or a method for producing the sintered body.

A sintered body including: zirconia containing a stabilizer; and a region in which an impact mark is formed when an impact force is applied.

In an aspect, a Co.sub.2Z ferrite has the formula: (Ba.sub.1-xSr.sub.x).sub.3Co.sub.2+yM.sub.yFe.sub.24-2y-zO.sub.41. M is at least one of Mo, Ir, or Ru. The variable x can be 0 to 0.8, or 0.1 to 0.8. The variable y can be 0 to 0.8, or 0.01 to 0.8. The variable z can be −2 to 2. The Co.sub.2Z ferrite can have an average grain size of 5 to 100 nanometers, or 30 to 80, or 10 to 40 nanometers as measured using at least one of transmission electron microscopy, field emission scanning electron microscopy, or x-ray diffraction.

There is provided at least any of a layered body which has a change in color tone and in which it is unnecessary to select a colorant and the content of the colorant in consideration of a difference in the sintering behavior between layers, a precursor thereof, or a method for producing these. Provided is a layered body which has a structure, in which two or more layers containing stabilizer-containing zirconia and a colorant are layered, and in which types and contents of the colorants contained in the layers are equal to each other, the layered body including at least: a first layer containing a colorant and zirconia which has a stabilizer content of higher than or equal to 3.3 mol %; and a second layer containing a colorant and zirconia which has a stabilizer content different from that of the zirconia contained in the first layer.

A ferrite sintered magnet comprises a plurality of main phase grains containing a ferrite having a hexagonal structure, wherein at least some of the main phase grains are core-shell structure grains each having a core and a shell covering the core; and wherein the minimum value of the content of La in the core is [La]c atom %; the minimum value of the content of Co in the core is [Co]c atom %; the maximum value of the content of La in the shell is [La]s atom %; the maximum value of the content of Co in the shell is [Co]s atom %; [La]c+[Co]c is 3.08 atom % or more and 4.44 atom % or less; and [La]s+[Co]s is 7.60 atom % or more and 9.89 atom % or less.

The present invention provides a ferrite sintered magnet comprising ferrite crystal grains having a hexagonal structure, wherein the ferrite sintered magnet comprises metallic elements at an atomic ratio represented by formula (1). In formula (1), R is at least one element selected from the group consisting of Bi and rare-earth elements, and R comprises at least La. In formula (1), w, x, z and m satisfy formulae (2) to (5). The above-mentioned ferrite sintered magnet further has a coefficient of variation of a size of the crystal grains in a section parallel to a c axis of less than 45%.
Ca.sub.1-w-xR.sub.wSr.sub.xFe.sub.zCo.sub.m  (1)
0.360≤w≤0.420  (2)
0.110≤x≤0.173  (3)
8.51≤z≤9.71  (4)
0.208≤m≤0.269  (5)

When the porous ceramic structure contains Co together with Fe or Mn, the Co content is higher than or equal to 0.1 mass % and lower than or equal to 3.0 mass % in terms of Co.sub.3O.sub.4, and when the porous ceramic structure contains Co without containing Fe and Mn, the Co content is higher than or equal to 0.2 mass % and lower than or equal to 6.0 mass % in terms of Co.sub.3O.sub.4. The ratio of the sum of the Fe content in terms of Fe.sub.2O.sub.3, the Mn content in terms of Mn.sub.2O.sub.3, and the Co content in terms of Co.sub.3O.sub.4 to the Ce content in terms of CeO.sub.2 is higher than or equal to 0.8 and lower than or equal to 9.5.

In an aspect, a ferrite composition comprises a Ru—Co.sub.2Z ferrite having the formula: (Ba.sub.3-xM.sub.x)Co.sub.2(M′Ru).sub.yFe.sub.24-2y-zO.sub.41, wherein M is at least one of Sr, Pb, or Ca; M′ is at least one of Co, Zn, Mg, or Cu; x is 1 to 3; y is greater than 0 to 2; and z is −4 to 4. In another aspect, an article comprises the ferrite composition. In yet another aspect, method of making the ferrite composition comprises mixing ferrite precursor compounds comprising Fe, Ba, Co, and Ru; and sintering the ferrite precursor compounds in an oxygen atmosphere to form the Ru—Co.sub.2Z ferrite.

A ferrite ceramic composition includes, as main components, from 27.0 mol % to 41.0 mol % of Fe in terms of Fe.sub.2O.sub.3, from 16.0 mol % to 24.0 mol % of Ni in terms of NiO, from 23.0 mol % to 37.0 mol % of Zn in terms of ZnO, from 5.0 mol % to 9.0 mol % of Cu in terms of CuO, and from 4.0 mol % to 14.0 mol % of Si in terms of SiO.sub.2, and as sub-components, relative to 100 parts by mass of the main components, from 0.3 parts by mass to 1.2 parts by mass of Bi in terms of Bi.sub.2O.sub.3, from 0.3 parts by mass to 1.2 parts by mass of Co in terms of Co.sub.3O.sub.4, from 0.01 parts by mass to 0.25 parts by mass of Mn in terms of Mn.sub.2O.sub.3, and from 0.003 parts by mass to 0.030 parts by mass of Cr in terms of Cr.sub.2O.sub.3.