The present invention relates to a ferrite particle containing a crystal phase component containing a perovskite crystal represented by a compositional formula: RZrO.sub.3 (provided that R represents an alkaline earth metal element), having a surface roughness Rz of 0.8 .Math.m or more and 3.5 .Math.m or less, and having a standard deviation Rzσ of the surface roughness Rz falling in a range represented by the following formula 0.15 × Rz ≤ Rzσ ≤ 0.60 × Rz. The ferrite particle can be used as an electrophotographic developer carrier core material. In addition, an electrophotographic developer carrier and an electrophotographic developer can be obtained.

An air-permeable member of the present disclosure includes a porous ceramic having a columnar or plate shape. A root mean square slope RΔq in a roughness curve of an outer peripheral surface of the porous ceramic is greater than a root mean square slope RΔq in a roughness curve of a main surface of the porous ceramic.

A dielectric ceramic composition contains dielectric particles containing a main component represented by a composition formula (Ba.sub.1-x-ySr.sub.xCa.sub.y).sub.m(Ti.sub.1-zZr.sub.z)O.sub.3 and grain boundaries present between the dielectric particles. The values of m, x, y, and z in the composition formula are all molar ratios. In the composition formula, 0.9≤m≤1.4, 0≤x<1.0, 0<y≤1.0, 0.9≤(x+y)≤1.0, and 0.9≤z≤1.0 are satisfied. The dielectric particles contain specific structural particles having a predetermined intragranular structure, and each of the specific structural particles intragranularly includes a first region and a second region having different Ca concentrations from each other. C2/C1 is less than 0.8 in which C1 is an average value of the Ca concentration in the first region and C2 is an average value of the Ca concentration in the second region.

Provided is an inorganic structure including a plurality of inorganic particles; and a binding part that covers a surface of each of the inorganic particles and binds the inorganic particles together, wherein the binding part contains: an amorphous compound containing silicon, oxygen, and one or more metallic elements; and fine particles having an average particle size of 100 nm or less. Also provided is a method for producing an inorganic structure including: a step for obtaining a mixture by mixing a plurality of inorganic particles, a plurality of amorphous silicon dioxide particles, and an aqueous solution containing a metallic element; and a step for pressurizing and heating the mixture under conditions of a pressure of 10 to 600 MPa and a temperature of 50 to 300° C.

A ceramic core includes sintered ceramic powder and a hole opening on a surface of the ceramic core and having an opening portion with a maximum size of 100 μm or less. A manufacturing method for a ceramic core includes: preparing an injection molding composition by mixing ceramic powder and a binder; manufacturing a ceramic compact by performing the injection molding of the injection molding composition; and manufacturing a ceramic core by sintering the ceramic compact, wherein cumulative percentage of coarse powder with a particle diameter of more than 50 μm included in the ceramic powder is 30% or less on an integrated volume particle size distribution curve of the ceramic powder.

Provided is a zirconia sintered body having both high translucency and high strength. The zirconia sintered body includes crystal grains that include a cubic domain and a tetragonal domain, wherein a stabilizer and lanthanum is dissolved as a solid solution therein. The sintered body can be obtained by a manufacturing method including: a mixing step of obtaining a mixed powder by mixing a zirconia source, a stabilizer source, and a lanthanum source; a molding step of obtaining a green body by molding the obtained mixed powder; a sintering step of obtaining a sintered body by sintering the obtained green body at a sintering temperature of 1650° C. or higher; and a temperature lowering step of lowering the temperature from the sintering temperature to 1000° C. at a temperature lowering rate exceeding 1° C./min.

A problem to be solved is to provide a method for processing zirconia without producing a monoclinic crystal. The solution is a method for processing zirconia, including the step of irradiating the zirconia with a laser with a pulse duration of 10.sup.−12 seconds to 10.sup.−15 seconds at an intensity of 10.sup.13 to 10.sup.15 W/cm.sup.2.

Disclosed is a method of manufacturing a porous ceramic body, which includes: (S1) mixing silica powders having a particle size of 0.045˜0.5 mm, zircon flour and wax, thus preparing a ceramic mixture; (S2) placing the ceramic mixture into a mold, thus producing a green body; and (S3) sintering the green body at high temperature, thus obtaining a porous ceramic body, wherein the silica having a particle size of 0.1˜0.5 mm is contained in an amount of 50˜80 wt % based on the total weight of the porous ceramic body; and also which produces a bulk porous ceramic body having good strength and leaching properties with excellent dimensional stability and shape stability.

A low-temperature, high stability co-fired microwave dielectric composite of ceramic and glass, including 85-99 wt % microwave dielectric ceramic of formula [1-y-z[(1−x)Mg.sub.2SiO.sub.4−xCa.sub.2SiO.sub.4]−yCaTiO.sub.3−zCaZrO.sub.3, wherein 0.2≦x≦0.7,0.05≦y≦0.3 and 0.02≦z≦0.15], and 1 to 15 wt % with Li.sub.2O—BaO—SrO—CaO—B.sub.2O.sub.3—SiO.sub.2 glass respectively made at a low sintering temperature of ceramic for co-firing with Ag or Cu electrode, employing eutectic phase of ceramic oxides to reduce its melting temperature, a low melting-point glass material with high chemical stability as a sintering aid added to oxides and raw material powders of Li.sub.2O, BaO, SrO, CaO, B.sub.2O.sub.3 and SiO.sub.2, obtained by combining and melting the ingredients in the temperature range between 1000 to 1300° C., quenching and crashing, and then adding it to the main ceramic oxides to form the final composition. This ceramic/glass composite material may be co-fired with an Ag and Cu electrode at 900° C.-970° C. for 0.5-4 hours in a protective atmosphere. After sintering, this dielectric material possesses efficacious microwave dielectric properties, dielectric constant between middle-K to low-K at 8.sup.−15, high quality factors, low dielectric loss, low temperature-capacitance coefficient and superior chemical stability suitable for manufacture of multilayer ceramic devices.

Embodiments of the present disclosure relate to articles, coated articles and methods of coating such articles with a rare earth metal containing oxide coating. The coating can contain at least a first metal (e.g., a rare earth metal, tantalum, zirconium, etc.) and a second metal that have been co-deposited onto a surface of the article. The coating can include a homogenous mixture of the first metal and the second metal and does not contain mechanical segregation between layers in the coating.