Provided are a zirconia sintered body capable of being widely used as a dental material, in particular, a zirconia sintered body capable of being applied to both a dental material for a back tooth and a dental material for a front tooth and a simple and easy method for manufacturing the zirconia sintered body.

The method for manufacturing a zirconia sintered body includes a molding step of molding a powder composition that has an yttria content of more than 3% by mole and 5.2% by mole or less and that contains a first zirconia powder having an yttria content of 2% by mole or more and 4% by mole or less and a second zirconia powder having an yttria content of more than 4% by mole and 6% by mole or less to obtain a green body, and a sintering step of sintering the green body to obtain a sintered body.

A composite sintered body, wherein the composite sintered body consists of ceramic composite sintered body, the ceramic composite sintered body comprises aluminum oxide as a main phase, and silicon carbide as a sub-phase, in which the composite sintered body has mullite in crystal grains of the aluminum oxide.

A ceramic material including Co.sub.0.5Ti.sub.0.5TaO.sub.4. The ceramic material is prepared as follows: 1) weighting and mixing raw powders of Co.sub.2O.sub.3, TiO.sub.2 and Ta.sub.2O.sub.5 proportioned according to the chemical formula of Co.sub.0.5Ti.sub.0.5TaO.sub.4, to yield a mixture; 2) mixing the mixture obtained in 1), zirconia balls, and deionized water according to a mass ratio of 1:4-6:3-6, ball-milling for 6-8 h, drying at 80-120 C., sieving with a 60-200 mesh sieve, calcining in air atmosphere at 800-1100 C. for 3-5 h, to yield powders comprising a main crystalline phase of Co.sub.0.5Ti.sub.0.5TaO.sub.4; and 3) mixing the powders obtained in 2), zirconia balls, and deionized water according to a mass ratio of 1:3-5:2-4, ball-milling for 4-6 h, and drying at 80-100 C.; adding a 2-5 wt. % of polyvinyl alcohol solution to a resulting product, granulating, sintering resulting granules at 1000-1100 C. in air atmosphere for 4-6 h.

An oxide sintered body having metal elements composed of In, Ga, Zn and Sn and containing a hexagonal layered compound represented by InGaO.sub.3(ZnO).sub.m (m is an integer of 1 to 6). When ratios (atomic %) of contents of In, Zn and Sn to all metal elements excluding oxygen contained in the oxide sintered body are taken as [In], [Zn] and [Sn], respectively, the relations [Zn]40 atomic %, [In]15 atomic %, [Sn]4 atomic % are satisfied.

A sintered material includes cubic boron nitride grains and a binder, a grain size D50 of the cubic boron nitride grains when a cumulative value of the cubic boron nitride grains is 50% in an area-based grain size distribution being more than 0.5 m and less than or equal to 5 m, more than or equal to 70 volume % and less than or equal to 98 volume % of the cubic boron nitride grains being included in the sintered material, the binder being composed of A.sub.1-xCr.sub.xN, where 0x1, and a remainder, the remainder being composed of at least one of a first element and a compound including the first element and a second element, the first element being one or more elements selected from a group consisting of W, Co, Ni, Mo, Al, and Cr, the second element being one or more elements selected from a group consisting of nitrogen, carbon, oxygen, and boron.

An oxide sintered body is provided which does not splash from the target surface even at the time of high power film formation, has a high film formation rate, and is used in a sputtering target capable of providing a high-refractive-index film. An oxide sintered body is used which contains zinc, niobium, aluminum and oxygen as constituent elements and in which
Nb/(Zn+Nb+Al)=0.076 to 0.289 and
Al/(Zn+Nb+Al)=0.006 to 0.031, where Zn, Nb and Al denote contents of zinc, niobium and aluminum, respectively.

A piezoelectric material includes: an oxide containing Na, Ba, Nb, Ti, and Mn, in which the oxide has a perovskite-type structure, a total amount of metal elements other than Na, Ba, Nb, Ti, and Mn contained in the piezoelectric material is 0.5 mol % or less with respect to a total amount of Na, Ba, Nb, Ti, and Mn, a molar ratio x of Ti to a total molar amount of Nb and Ti is 0.05x0.12, a molar ratio y of Na to Nb is 0.93y0.98, a molar ratio z of Ba to Ti is 1.09z1.60, a molar ratio m of Mn to the total molar amount of Nb and Ti is 0.0006m0.0030, and 1.07yz1.50 is satisfied.

Provided is a lead-free piezoelectric material reduced in dielectric loss tangent, and achieving both a large piezoelectric constant and a large mechanical quality factor. A piezoelectric material according to at least one embodiment of the present disclosure is a piezoelectric material including a main component formed of a perovskite-type metal oxide represented by the general formula (1): Na.sub.x+s(1y)(Bi.sub.wBa.sub.1sw).sub.1yNb.sub.yTi.sub.1yO.sub.3 (where 0.84x0.92, 0.84y0.92, 0.002(w+s)(1y)0.035, and 0.9w/s1.1), and a Mn component, wherein the content of the Mn is 0.01 mol % or more and 1.00 mol % or less with respect to the perovskite-type metal oxide.

The sputtering target 100 used in forming a positive electrode layer of a lithium-ion rechargeable battery is made of a sintered body including first particles 110 and second particles 120, the first particles 110 each containing lithium phosphorus oxide (e.g., Li.sub.3PO.sub.4) as an inorganic solid electrolyte, the second particles 120 each containing lithium transition metal oxide (e.g., LiNiO.sub.2) as a positive electrode active material.

Provided are a dielectric, a capacitor and a semiconductor device that include the dielectric, and a method of preparing the dielectric, the dielectric including: a composition represented by Formula 1; and an oxide including a perovskite type crystal structure having a polar space group or a non-polar space group other than a Pbnm space group:

<Formula 1>

A.sub.xB.sub.yO.sub.3- wherein, in Formula 1, A is a monovalent, divalent, or trivalent cation, B is a trivalent, tetravalent, or pentavalent cation, and 0.5x1.5, 0.5y1.5, and 00.5.