The object of the present invention is to provide a dielectric ceramic composition having even improved insulation specific resistance and highly accelerated lifetime. A dielectric ceramic composition comprising a dielectric particle having a core-shell structure including a main component expressed by a general formula ABO.sub.3 (A is Ba and the like; and B is Ti and the like) and a rare earth element component R, in which a shell part of the core-shell structure has an average rare earth element concentration C of 0.3 atom % or more, and a rare earth element concentration gradient S is 0.010 atom %/nmS0.009 atom %/nm or a rare earth element concentration variation satisfies /C0.15 (a is a standard deviation of a rare earth element concentration and C is an average rare earth element concentration).

A carbon foam comprising linear portions and node portions joining the linear portions, wherein the linear portions have a diameter of 0.1 m or more and 10.0 m or less, and the carbon foam has a surface with an area of 100 cm.sup.2 or more.

A dielectric porcelain composition having a main component of a lead-free perovskite type compound at least containing Ba, Ca, Ti, and Sb, and having a Curie temperature Tc of 140 C. or higher.

A dielectric composition with high voltage resistance and favorable reliability, and an electronic component using the composition, the composition containing a tungsten bronze type composite oxide represented by chemical formula (Sr.sub.1.00(s+t)Ba.sub.sCa.sub.t).sub.6.00xR.sub.x(Ti.sub.1.00(a+d)Zr.sub.aSi.sub.d).sub.x2.00(Nb.sub.1.00bTa.sub.b).sub.8.00xO.sub.30.00, wherein R is at least one element selected from Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and s, t, x, a, b, and d satisfy 0s1.00, 0t1.00, 0s+t1.00, 0x3.00, 0.01a0.98, 0b1.00, 0.02d0.15, and 0.03a+d1.00. At least one element selected from Mn, Mg, Co, V, W, Mo, Li, B, and Al are contained as a sub component in 0.10 mol or more and 20.00 mol or less with respect to 100 mol of the main component.

The present invention provides a piezoelectric material not containing lead and potassium, showing satisfactory insulation and piezoelectricity, and having a high Curie temperature. The invention relates to a piezoelectric material includes a main component containing a perovskite-type metal oxide represented by Formula (1): (Na.sub.xBa.sub.1-y)(Nb.sub.yTi.sub.1-y)O.sub.3 (wherein, 0.80x0.94 and 0.83y0.94), and an additive component containing at least one element selected from Mn and Ni, wherein the content of the Ni is 0 mol or more and 0.05 mol or less based on 1 mol of the perovskite-type metal oxide, and the content of the Mn is 0 mol or more and 0.005 mol or less based on 1 mol of the perovskite-type metal oxide.

Disclosed are a manganese zinc ferrite, a preparation method therefor and the use thereof. The manganese zinc ferrite comprises main components and auxiliary components, wherein the main components comprise iron oxide, zinc oxide and manganese monoxide; and according to the total amount of 100 mol % of the main components, the content of ferric oxide is 52.75-53.15 mol %, the content of zinc oxide is 9.1-10.7 mol %, and the balance being manganese monoxide.

A ceramic electronic device includes a multilayer structure having a parallelepiped shape in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately stacked in a vertical direction, the plurality of internal electrode layers being alternately exposed to two end faces of the parallelepiped shape. A side margin section is a section covering edges of the plurality of internal electrode layers in an extension direction toward two side faces of the parallelepiped shape. The side margin section has a structure in which a plurality of dielectric layers, each containing a ceramic as a main component, and a plurality of conductive layers, each containing a metal as a main component, are alternately stacked in the vertical direction. The plurality of conductive layers are respectively spaced and separated from the plurality of internal electrode layers.

A ferrite sintered body contains Fe, Mn, Zn, Cu, and Ni. Supposing that Fe, Mn, Zn, Cu, and Ni are converted into Fe.sub.2O.sub.3, Mn.sub.2O.sub.3, ZnO, CuO, and NiO, respectively, and the sum of the contents of Fe.sub.2O.sub.3, Mn.sub.2O.sub.3, ZnO, CuO, and NiO is 100 mol %, the sum of the contents of Fe.sub.2O.sub.3 and Mn.sub.2O.sub.3 is 48.47 mol % to 49.93 mol %, the content of Mn.sub.2O.sub.3 is 0.07 mol % to 0.37 mol %, the content of ZnO is 28.95 mol % to 33.50 mol %, and the content of CuO is 2.98 mol % to 6.05 mol %. Furthermore, 102 ppm to 4,010 ppm Zr in terms of ZrO.sub.2 and 10 ppm to 220 ppm Al in terms of Al.sub.2O.sub.3 are contained per 100 parts by weight of the sum of the amounts of contained Fe.sub.2O.sub.3, Mn.sub.2O.sub.3, ZnO, CuO, and NiO.

A multiphase ferrite composition includes a primary phase consisting of a MnZn ferrite matrix; and 0.01 to 10 weight percent microscaled inclusion particles comprising an orthoferrite RFeO3 wherein R is a rare earth ion, yttrium iron garnet (YIG), or a combination thereof, wherein the microscaled inclusion particles have an average particle size (D50) of 0.1 micron to 5 microns, and wherein the D50 of the microscaled inclusion particles is smaller than the average particle size (D50) of the MnZn ferrite particles; and optionally 0.01 to 5 weight percent additive; wherein weight percent is based on the total weight of the multiphase ferrite composition. A method of manufacturing the multiphase ferrite composition is also disclosed.

The present invention provides a sintering control method of ceramic manufacturing. The method includes the following steps: S1: preparing a pore-forming agent containing a porogen; S2: mixing the pore-forming agent with a ceramic slurry and forming a greenpart; S3: sintering the greenpart at a first temperature in an oxygen-free environment to form a semi-finished object; and S4: sintering the semi-finished object at a second temperature in an oxygen-containing environment to form a ceramic article. Wherein, the first temperature is higher than the second temperature. While the porogen is a carbon-based material, the second temperature is from 300 C. to 600 C., and the porosity of the ceramic article may reach 30% to 70%. By this method, the property of the ceramic article (including mechanical strength, porosity, pore shape and size) can be designed according to requirement and controlled for quality assurance.