An oxide ceramic expressed by the general formula Sr.sub.2-xBa.sub.xCo.sub.2-yMg.sub.yFe.sub.12-zAl.sub.zO.sub.22, where 0.7x1.3, 0<y0.8, and 0.8z1.2.

The invention relates to a method for producing a ceramic proppant, including a step for preparing an original charge material, involving the grinding of source materials, particularly magnesium-containing materials, and auxiliary materials, thus producing a charge material, granulating the charge material so as to produce granules of a proppant precursor, and firing the granules of proppant precursor, thus producing proppant granules, wherein the method includes a step for pre-firing the magnesium-containing material in a reducing atmosphere. The invention also relates to a ceramic proppant produced via the indicated method.

Embodiments of the present disclosure are drawn to a wave-absorbing material that includes a main composition, an auxiliary composition, and a sintering additive. The main composition includes at least one of Fe.sub.2O.sub.3, MnO, ZnO, and MgO. The auxiliary composition includes at least one of CeO.sub.2 and P.sub.2O.sub.5. The molar ratio of CeO.sub.2 to P.sub.2O.sub.5 ranges from about 1:1 to about 2:1. A method for preparing the wave-absorbing material is also provided.

The invention relates to a method for producing a ceramic proppant, including a step for preparing an original charge material, involving the grinding of source materials, particularly magnesium-containing materials, and auxiliary materials, thus producing a charge material, granulating the charge material so as to produce granules of a proppant precursor, and firing the granules of proppant precursor, thus producing proppant granules, wherein the method includes a step for pre-firing the magnesium-containing material in a reducing atmosphere. The invention also relates to a ceramic proppant produced via the indicated method.

A functional patch for a pad is beneficial to a human body and solves the problems entailed in various sanitary pads having a multi-layer configuration such as a sanitary napkin, a diaper for an infant or an adult, a sanitary sheet, a mask, etc. The functional patch is inserted into and attached to the pad formed in a multi-layer. Thus, functionality of a sanitary pad may be improved.

An oxide ceramic expressed by the general formula Sr.sub.2-xBa.sub.xCo.sub.2-yMg.sub.yFe.sub.12-zAl.sub.zO.sub.22, where 0.7x1.3, 0<y0.8, and 0.8z1.2.

The present invention relates to a ferrite particle, containing a crystal phase component containing a perovskite crystal represented by the compositional formula: RZrO.sub.3 (provided that R represents an alkaline earth metal element), and having an apparent density in a range represented by the following formula:
1.90Y2.45
provided that Y in the formula is the apparent density (g/cm.sup.3) of the ferrite particle.

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 m or more and 3.5 m or less, and having a standard deviation Rz of the surface roughness Rz falling in a range represented by the following formula 0.15RzRz0.60Rz. 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.

The present invention relates to a ferrite particle containing a crystal phase component containing a perovskite-type crystal represented by a composition formula of RZrO3 (wherein R is an alkaline earth metal element), and a Mg content of 0.45 mass % or less. The present invention also relates to a carrier core material for an electrophotographic developer, containing the ferrite particle; a carrier for an electrophotographic developer, containing the ferrite particle and a resin coating layer provided on a surface of the ferrite particle; and an electrophotographic developer containing the carrier for an electrophotographic developer and a toner.