The present invention provides a high thermal conductive silicon nitride sintered body having a thermal conductivity of 50 W/m.Math.K or more and a three-point bending strength of 600 MPa or more, wherein when an arbitrary cross section of the silicon nitride sintered body is subjected to XRD analysis and highest peak intensities detected at diffraction angles of 29.3±0.2°, 29.7±0.2°, 27.0±0.2°, and 36.1±0.2° are expressed as I.sub.29.3°, I.sub.29.7°, I.sub.27.0°, and I.sub.36.1°, a peak ratio (I.sub.29.3°)/(I.sub.27.0°+I.sub.36.1°) satisfies a range of 0.01 to 0.08, and a peak ratio (I.sub.29.7°)/(I.sub.27.0°+I.sub.36.1°) satisfies a range of 0.02 to 0.16. Due to above configuration, there can be provided a silicon nitride sintered body having a high thermal conductivity of 50 W/m.Math.K or more, and excellence in insulating properties and strength.

A ceramic tool material, in particular with piezoelectric effect and a preparation method thereof, and a cutting tool. The ceramic tool material includes the following raw materials by weight: 30-70 parts of matrix material, 30-70 parts of piezoelectric material, 5-10 parts of binder, and 10-20 parts of reinforcing phase and can be made into cutting tools. The cutting tool has a piezoelectric effect and excellent mechanical properties and can convert the cutting force signal into the charge signal during machining. By collecting charge signals, a cutting force can be measured and ceramic cutting tool condition can be monitored. Cutting force measurement function and high mechanical properties are integrated. A ceramic tool material with piezoelectric effect can measure the cutting force on the premise by meeting the cutting performance requirements.

A pore-free ceramic is provided that has a high modulus of elasticity and a low coefficient of thermal expansion. A process for producing a corresponding ceramic is also provided. The pore free ceramic is a dimensionally stable substrate material in applications subjected to temperature gradients including semiconductor manufacture.

Provided is a piezoelectric ceramics having a gradual change in piezoelectric constant depending on an ambient temperature. Specifically, provided is a single-piece piezoelectric ceramics including as a main component a perovskite-type metal oxide represented by a compositional formula of ABO.sub.3, wherein an A site element in the compositional formula contains Ba and M.sub.1, the M.sub.1 being formed of at least one kind selected from the group consisting of Ca and Bi, wherein a B site element in the compositional formula contains T1 and M.sub.2, the M.sub.2 being formed of at least one kind selected from the group consisting of Zr, Sn, and Hf, wherein concentrations of the M.sub.1 and the M.sub.2 change in at least one direction of the piezoelectric ceramics, and wherein increase and decrease directions of concentration changes of the M.sub.1 and the M.sub.2 are directions opposite to each other.

A method of manufacturing a dielectric for a capacitor and a dielectric for a capacitor manufactured thereby are provided. A dielectric for a capacitor is prepared by calcining a precursor mixture containing lead, lanthanum, zirconium, and titanium to produce calcined powder, adding additives including sodium, potassium, and the like to the powder, and sintering the mixture at a low temperature, whereby the dielectric has a high density and a large dielectric constant.

The present disclosure relates to a method for the preparation of a precursor solution for a ceramic of the BZT-aBXT type wherein X is selected from Ca, Sn, Mn and Nb and a is a molar fraction selected in the range between 0.10 and 0.90 comprising the steps of: a) dissolving at least one barium precursor compound and at least one precursor compound selected from the group consisting of a calcium precursor compound, a tin precursor compound, a manganese precursor compound and a niobium precursor compound in a linear or branched anhydrous alkyl alcohol containing from 2 to 6 carbon atoms and, after dissolution, dehydrating by stripping, to obtain a first solution; b) dissolving at least one zirconium precursor compound and at least one titanium precursor compound in a linear or branched anhydrous alkyl alcohol containing from 2 to 6 carbon atoms in the presence of an anhydrous chelating agent to obtain a second solution; c) joining said first and second solutions in an anhydrous environment and dehydrating by stripping to obtain said precursor solution. It also relates to a precursor solution, to a method for the preparation of a film of a piezoelectric material, to a piezoelectric material and to an electronic device comprising this piezoelectric material.

A dielectric ceramic composition contains dielectric particles containing a main component represented by a composition formula (Ba.sub.1-x-ySr.sub.xCa.sub.y).sub.m(Ti.sub.1-zZr.sub.z)O.sub.3 and grain boundaries present between the dielectric particles. The values of m, x, y, and z in the composition formula are all molar ratios. In the composition formula, 0.9≤m≤1.4, 0≤x<1.0, 0<y≤1.0, 0.9≤(x+y)≤1.0, and 0.9≤z≤1.0 are satisfied. The dielectric particles contain specific structural particles having a predetermined intragranular structure, and each of the specific structural particles intragranularly includes a first region and a second region having different Ca concentrations from each other. C2/C1 is less than 0.8 in which C1 is an average value of the Ca concentration in the first region and C2 is an average value of the Ca concentration in the second region.

A piezoelectric material including a perovskite-type metal oxide represented by the following general formula (1); Bi; and Mn, wherein the content of Bi is 0.1-0.5 mol % with respect to 1 mol of the metal oxide, the content of Mn is 0.3-1.5 mol % with respect to 1 mol of the metal oxide, and the piezoelectric material satisfies (L.sub.4−L.sub.5)/L.sub.5≧0.05 and (L.sub.8−L.sub.9)/L.sub.9≧0.05 when the lengths of twelve Bi—O bonds with Bi that is located at a 12-fold site with respect to O in a perovskite-type unit cell as a starting point are taken to be L.sub.1 to L.sub.12 in length order:

(Ba.sub.1-xM1.sub.x)(Ti.sub.1-yM2.sub.y)O.sub.3  (1)

wherein 0≦x≦0.2, 0≦y≦0.1, and M1 and M2 are mutually different metal elements which have a total valence of +6 and are selected from other elements than Ba, Ti, Bi and Mn.

A dielectric composition is provided. The dielectric composition includes: a main component made of: a first complex oxide expressed by a chemical formula {K(Ba.sub.1-xSr.sub.x).sub.2Nb.sub.5O.sub.15}; and a second complex oxide expressed by a chemical formula that differs the chemical formula of the first complex oxide. The second complex oxide is a complex oxide expressed by one of chemical formulae: {(Ca.sub.1-ySr.sub.y)(Zr.sub.1-zTi.sub.z)O.sub.3}; {Ba(Ti.sub.1-uZr.sub.u)O.sub.3}; {(Ca.sub.1-vSr.sub.v)TiSiO.sub.5}; and {(Ba.sub.1-wRe.sub.2w/3)Nb.sub.2O.sub.6}, x satisfies 0.35≦x≦0.75, and a satisfies 0.25≦a≦0.75 when a molar ratio between the first and second complex oxides is defined by a:b in an order and a+b=1.00.

Disclosed herein are methods for preparing a titanate compound powder comprising titanate compound particles having a controlled particle size and/or particle size distribution. The methods include mixing at least one first inorganic compound chosen from sources of a first metal or metal oxide, at least one second inorganic compound chosen from sources of titania, and at least one binder to form a mixture; calcining the mixture to form a polycrystalline material comprising a plurality of titanate compound grains and a plurality of micro-cracks; and breaking the polycrystalline material along at least a portion of the microcracks. Also disclosed are titanate compound powders having a controlled particle size distribution, ceramic batch compositions comprising the powders, and ceramic articles prepared from the batch compositions.