A cubic boron nitride sintered material includes: more than 80 volume % and less than 100 volume % of cubic boron nitride grains; and more than 0 volume % and less than 20 volume % of a binder phase. The binder phase includes: at least one selected from a group consisting of a simple substance, an alloy, and an intermetallic compound selected from a group consisting of a group 4 element, a group 5 element, a group 6 element in a periodic table, aluminum, silicon, cobalt, and nickel. A dislocation density of the cubic boron nitride grains is more than or equal to 1×10.sup.15/m.sup.2 and less than or equal to 1×10.sup.17/m.sup.2.

A lead-free lithium doped potassium sodium niobate piezoelectric ceramic material in powdered form and having a single crystalline phase and uses thereof are described. Methods of making the said piezoelectric ceramic material are also described.

A ceramic composite sintered body, including: a metal oxide as a main phase, and silicon carbide as a sub-phase, in which crystal grains of the silicon carbide are dispersed in crystal grains of the metal oxide and at crystal grain boundaries of the metal oxide, and an average crystal grain size of the silicon carbide dispersed at the crystal grain boundaries of the metal oxide is 0.30 μm or less.

Provided is at least one of a zirconia sintered body and a method for producing the same. The zirconia sintered body can be used in a wide range of applications compared with ceramic joined bodies of the related art that include transparent zirconia. A zirconia sintered body includes a transparent zirconia portion and an opaque zirconia portion, wherein the zirconia sintered body has a biaxial flexural strength of greater than or equal to 300 MPa.

A sputtering target containing silicon nitride (Si.sub.3N.sub.4) with reduced specific resistance of is provided. A sputtering target including Si.sub.3N.sub.4, SiC, MgO and TiCN, wherein a specific resistance of the sputtering target is 10 mΩ.Math.cm or less.

An electro-conductive B.sub.4C—TiB.sub.2 has a microstructure in which large B.sub.4C grains are coated by small TiB.sub.2 grains. The composite ceramic includes 10˜30% by volume of TiB.sub.2. A method for preparing the electro-conductive B.sub.4C—TiB.sub.2 composite ceramic includes: (1) weighing B.sub.4C, TiC, and amorphous B powder; (2) mixing evenly and drying thoroughly the powders; and (3) loading the mixed powder into a graphite mold; and placing the graphite mold in a spark plasma sintering furnace for sintering under vacuum, where the sintering is performed at 2000° C. and 50 MPa for 5˜20 min.

A cBN sintered compact comprising a cubic boron nitride and a ceramic binder phase, wherein a cubic C-containing Ta compound in an amount of 1.0 to 15.0 vol % is dispersed in the ceramic binder phase and has a mean particle diameter of 50 to 500 nm.

Provided is a method for producing a calcium carbonate sintered body whereby a good sintered body can be obtained without having to use any sintering aid. A method for producing a calcium carbonate sintered body includes the steps of: compacting calcium carbonate to make a green body; heating the green body under a condition of a temperature of 500° C. or lower to remove an organic component contained in the green body; and sintering the green body under conditions of a carbon dioxide atmosphere and a temperature of 450° C. or higher to obtain a calcium carbonate sintered body.

A ferrite sintered magnet has a ferrite phase having a magnetoplumbite-type crystal structure, and contains at least a metal element A, a metal element R, Fe, Co, Zn, and B. The element A is at least one kind of element selected from the group consisting of Sr, Ba, Ca, and Pb, and essentially includes Ca. The element R is at least one kind of element selected from the group consisting of Bi and rare-earth elements including Y, and essentially includes La. Atomic ratios of the metal elements satisfy the following expressions.

A.sub.1-rR.sub.rFe.sub.xCo.sub.yZn.sub.z  (1)

0.40≤r≤0.70  (2)

8.20≤x≤9.34  (3)

0.05<y≤0.50  (4)

0<z≤0.20  (5)

The content of Si is 0 to 0.60% by mass in terms of SiO.sub.2, and the content of B is 0.01 to 0.70% by mass in terms of B.sub.2O.sub.3.

A cubic boron nitride sintered material includes: more than or equal to 80 volume % and less than or equal to 96 volume % of cubic boron nitride grains; and a binder, wherein the binder includes tungsten carbide, cobalt, and an aluminum compound, and Ha/Hb≥0.40 is satisfied, where Hb represents a hardness of the cubic boron nitride sintered material and Ha represents a hardness of the cubic boron nitride sintered material after performing acid treatment onto the cubic boron nitride sintered material to substantially remove the binder in the cubic boron nitride sintered material.