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 electrochemical cell has an anode, a cathode, and a solid electrolyte layer. The cathode contains a perovskite oxide expressed by the general formula ABO.sub.3 and including at least one of Sr and La at the A site as a main component. The solid electrolyte layer is disposed between the anode and the cathode. The cathode includes a solid electrolyte layer-side region within 3 m from a surface of the solid electrolyte layer side. The solid electrolyte layer-side region includes a main phase which is configured by the perovskite oxide and a second phase which is configured by CO.sub.3O.sub.4 and (Co, Fe).sub.3O.sub.4. An occupied surface area ratio of the second phase in a cross section of the solid electrolyte layer-side region is less than or equal to 10.5%.

A solid electrolyte capable of securing grain boundary resistance even when firing is performed at a relatively low temperature and a battery using the solid electrolyte are provided. The solid electrolyte includes a first electrolyte which contains a lithium composite metal compound, and a second electrolyte which contains Li and at least two kinds of metal elements selected from group 5 elements in period 5 or higher or group 15 elements in period 5 or higher.

A garnet-type ion-conducting oxide configured to inhibit lithium carbonate formation on the surface of crystal particles thereof, and a method for producing an oxide electrolyte sintered body using the garnet-type ion-conducting oxide. The garnet-type ion-conducting oxide represented by a general formula (Li.sub.x-3y-z, E.sub.y, H.sub.z)L.sub.?M.sub.62 O.sub.?(where E is at least one kind of element selected from the group consisting of Al, Ga, Fe and Si; L is at least one kind of element selected from an alkaline-earth metal and a lanthanoid element: M is at least one kind of element selected from a transition element which be six-coordinated with oxygen and typical elements in groups 12 to 15 of the periodic table; 3?x?3y?z?; 0?y?0.22; C?z?2.8; 2.5???3.5; 1.5???2.5; and 11???13), wherein a half-width of a diffraction peak which has a highest intensity and which is observed at a diffraction angle (2?) in a range of from 29? to 32? as a result of X-ray diffraction measurement using CuK? radiation, is 0.164? or less.

A cBN sintered material cutting tool is provided. The cBN cutting tool includes a cutting tool body, which is a sintered material including cBN grains and a binder phase, wherein the sintered material comprises: the cubic boron nitride grains in a range of 40 volume % or more and less than 60 volume %; and Al in a range from a lower limit of 2 mass % to an upper limit Y, satisfying a relationship, Y=0.1X+10, Y and X being an Al content in mass % and a content of the cubic boron nitride grains in volume %, respectively, the binder phase comprises: at least a Ti compound; Al.sub.2O.sub.3; and inevitable impurities, the Al.sub.2O.sub.3 includes fine Al.sub.2O.sub.3 grains with a diameter of 10 nm to 100 nm dispersedly formed in the binder phase, and there are 30 or more of the fine Al.sub.2O.sub.3 grains generated in an area of 1 m1 m in a cross section of the binder phase.

A sputtering target including an oxide that includes an indium element (In), a tin element (Sn), a zinc element (Zn) and an aluminum element (Al), and including a homologous structure compound represented by InAlO.sub.3(ZnO).sub.m (m is 0.1 to 10), wherein the atomic ratio of the indium element, the tin element, the zinc element and the aluminum element satisfies specific requirements.

A method capable of obtaining pure single phase hexagonal diamond in an industrially usable size (bulk) is provided. Highly oriented and highly crystallized graphite having a mosaic spread of 5 or less is used as a starting material, and is subjected to a temperature ranging from 1000 to 1500 C. at a pressure ranging from 20 to 25 GPa. The size of the bulk sintered body of pure single-phase hexagonal diamond obtained by this method depends on the size of the starting graphite. However, as long as the pressure and temperature can be entirely provided (i.e., as long as the adequate high pressure and temperature are applied to the sample chamber of high pressure apparatus), any desired size can be obtained.

Disclosed is a (K,Na)NbO.sub.3 (abbreviated by KNN)-based single crystal ceramic. The KNN-based single crystal ceramic according to the present disclosure is formulated by (K.sub.0.5x/2Na.sub.0.5x/2y.sub.y/2M.sub.x+y/2)Nb.sub.1x/3+yO.sub.3, wherein M indicates a metal having a different valence from Na, and indicates a metal vacancy. The above formulated KNN-based single crystal ceramic allows compensating for the volatilization of Na in a growing grain due to the addition of M.sup.2+ ions, and substituting M.sup.2+ ions for Na.sup.+ ions to form metal vacancies, thereby making possible the single crystal growth.

A polycrystalline diamond comprising diamond particles, wherein: the content of the diamond particles is more than 99% by volume based on the total volume of the polycrystalline diamond: the median diameter d50 of the diamond particles is 10 nm or more and 200 nm or less; and the dislocation density of the diamond particles is 0.1?10.sup.15 m.sup.?2 or more and less than 2.0?10.sup.15 m.sup.?2.

A sputtering target having a composition of LiCoO.sub.2, wherein a resistivity of the target is 100 cm or less, and a relative density is 80% or higher. The sputtering target of the present invention is effective for use in forming a positive electrode thin film in all-solid-state thin-film lithium ion secondary batteries equipped in vehicles, information and communication electronics, household appliances, and the like.