The present invention relates to a ceramic comprising (or consisting essentially of) a solid solution containing Bi, K, Ti and Fe (and optionally Pb) which exhibits piezoelectric behaviour.

A process for producing an ordered martensitic iron nitride powder that is suitable for use as a permanent magnetic material is provided. The process includes fabricating an iron alloy powder having a desired composition and uniformity; nitriding the iron alloy powder by contacting the material with a nitrogen source in a fluidized bed reactor to produce a nitride iron powder; transforming the nitride iron powder to a disordered martensitic phase; annealing the disordered martensitic phase to an ordered martensitic phase; and separating the ordered martensitic phase from the iron nitride powder to yield an ordered martensitic iron nitride powder.

The piezoelectric material of the present invention includes a main component composed of a perovskite-type metal oxide represented by Formula (1), at least one of Mn and Ni, and Mg. The content of 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 Mn is 0 mol or more and 0.005 mol or less based on 1 mol of the perovskite-type metal oxide, provided that the content of Mn and the content of Ni are not simultaneously 0 mol. The content of Mg is 0.001 mol or more and 0.020 mol or less based on 1 mol of the perovskite-type metal oxide. Formula (1): (Na.sub.xBa.sub.1-y)(Nb.sub.yTi.sub.1-y)O.sub.3 (where x is 0.83 or more and 0.95 or less, y is 0.85 or more and 0.95 or less, and x/y is 0.95 or more and 1.05 or less).

A sintered compact magnesium oxide target for sputtering has a purity of 99.99 wt % or higher excluding C, a density of 3.57 g/cm.sup.3 or higher, and a whiteness of 60% or less. To uniformly deposit a magnesium oxide film, a magnesium oxide target having a higher purity and a higher density is demanded. An object is to provide a target capable of realizing the above and a method for producing such a target. While a magnesium oxide sintered compact sputtering target is produced by hot-pressing a raw material powder, there is a problem in that color shading occurs in roughly 60 (within a circle having a diameter of 60 mm) at the center part of the target. Conventionally, no particularly attention was given to this problem. However, in recent years, it has become necessary to investigate and resolve this problem in order to improve the deposition quality.

A sintered compact magnesium oxide target for sputtering has a purity of 99.99 wt % or higher excluding C, a density of 3.57 g/cm.sup.3 or higher, and a whiteness of 60% or less. To uniformly deposit a magnesium oxide film, a magnesium oxide target having a higher purity and a higher density is demanded. An object is to provide a target capable of realizing the above and a method for producing such a target. While a magnesium oxide sintered compact sputtering target is produced by hot-pressing a raw material powder, there is a problem in that color shading occurs in roughly 60 (within a circle having a diameter of 60 mm) at the center part of the target. Conventionally, no particularly attention was given to this problem. However, in recent years, it has become necessary to investigate and resolve this problem in order to improve the deposition quality.

A multilayer ceramic capacitor that includes a laminated body having a plurality of ceramic layers including crystal grains that have a perovskite structure, and a plurality of internal electrode layers; and external electrodes on first and second end surfaces of the laminated body and electrically connected to respective sets of the plurality of internal electrodes. In the ceramic layers, when the content of Ti is 100 parts by mol, the ceramic layers contain Ca at 0.10 to 15.00 parts by mol; Mg at 0.0010 to 0.0097 parts by mol; R at 0.50 to 4.00 parts by mol; M at 0.10 to 2.00 parts by mol; and Si at 0.50 to 2.00 parts by mol, and core parts of the crystal grains contain Ca.

An yttrium oxyfluoride is represented by YOF and is stabilized by a fluoride represented by CaF.sub.2. Preferably, the number of moles of Ca with respect to 100 mol of yttrium is from 8 to 40 mol. A powder material is made of a first powder mixture including a calcium fluoride powder represented by CaF.sub.2 and an yttrium oxyfluoride powder represented by YOF, or a second powder mixture including a calcium fluoride powder represented by CaF.sub.2, an yttrium fluoride powder represented by YF.sub.3, and an yttrium oxide powder represented by Y.sub.2O.sub.3. A production method involves firing a molded product of the first or second powder mixture under predetermined conditions.

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, 0.80?x?0.94 and 0.83?y?0.94), 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.

The present invention relates to a ceramic comprising (or consisting essentially of) a solid solution containing Bi, K, Ti and Fe (and optionally Pb) which exhibits piezoelectric behavior.

A sintered compact magnesium oxide target for sputtering having a purity of 99.99 wt % or higher excluding C, a density of 3.57 g/cm.sup.3 or higher, and a whiteness of 60% or less. In order to uniformly deposit a magnesium oxide film, a magnesium oxide target having a higher purity and a higher density is being demanded. An object of this invention is to provide a target capable of realizing the above, and a method for producing such a target. While a magnesium oxide sintered compact sputtering target is produced by hot-pressing a raw material powder, there is a problem in that color shading occurs in roughly 60 (within a circle having a diameter of 60 mm) at the center part of the target. Conventionally, no particularly attention was given to this problem. However, in recent years, it has become necessary to investigate and resolve this problem in order to improve the deposition quality.