Disclosed herein are compounds, methods, and tools which comprise tungsten borides and mixed transition metal borides.

One aspect of the heat insulator of the present invention includes a porous sintered body having a porosity of 70 vol % or more and less than 91 vol %, and pores having a pore size of 0.8 μm or more and less than 10 μm occupy 10 vol % or more and 70 vol % or less of the total pore volume, while pores having a pore size of 0.01 μm or more and less than 0.8 μm occupy 5 vol % or more and 30 vol % or less of the total pore volume. The porous sintered body is formed from an MgAl.sub.2O.sub.4 (spinel) raw material and fibers formed of an inorganic material, the heat conductivity of the heat insulator at 1000° C. or more and 1500° C. or less is 0.40 W/(m.Math.K) or less, and the weight ratio of Si relative to Mg in the porous sintered body is 0.15 or less.

A method for producing a multilayer ceramic capacitor that includes preparing a dielectric ceramic material by mixing a perovskite compound, a Re compound, a Mn compound, a Mg compound, and a Si compound. The perovskite compound contains Ba and Ti and has 1.2×10.sup.15 or more and 4.5×10.sup.15 or less Ba vacancies per gram. Re in the Re compound is at least one element selected from Y, Gd, Tb, Dy, Ho, Er, and Yb. Green sheets containing the dielectric ceramic material are then formed. Inner electrode patterns are then formed on some of the green sheets. An unsintered capacitor body is then formed by stacking the green sheets, some of which have the inner electrode patterns formed thereon. Sintering of the unsintered capacitor body is then conducted.

The present invention provides a piezoelectric material not containing lead and potassium, having a high relative density, a high Curie temperature, and a high mechanical quality factor, and exhibiting good piezoelectricity. The piezoelectric material contains 0.04 percent by mole or more and 2.00 percent by mole or less of Cu relative to 1 mol of metal oxide represented by General formula (1) below.
((Na.sub.1-zLi.sub.z).sub.xBa.sub.1-y)(Nb.sub.yTi.sub.1-y)O.sub.3 (in Formula, 0.70≦x≦0.99, 0.75≦y≦0.99, and 0<z<0.15, and x<y)  General formula (1)

The aim of the present invention lies in providing a dielectric composition which has a relatively high dielectric constant of 800 or greater, and which has relatively low dielectric loss of 4% or less when a DC bias of at least 8 V/ym is applied, and also in providing a dielectric element employing said dielectric composition, an electronic component, and a laminated electronic component. A dielectric composition having a main component represented by (Bi.sub.aNa.sub.bSr.sub.cBa.sub.d) (α.sub.xTi.sub.1-x) O.sub.3, characterized in that a is at least one selected from Zr and Sn; and a, b, c, d and x satisfy the following: 0.140≦a≦0.390, 0.140≦b≦0.390, 0.200≦c≦0.700, 0.020≦d≦0.240, 0.020≦x≦0.240 and 0.950<a+b+c+d≦1.050.

An electrocaloric effect element includes a laminate including an electrode layer mainly including Pt and a ceramic layer that are stacked, in which the ceramic layer has a perovskite structure and mainly includes a ceramic including Pb, Sc, and Ta, where a content ratio of Sc is y, a content ratio of Ta is 1−y, and a range of the y is about 0.450≤y≤about 0.495.

A semiconductor ceramic composition represented by formula (1),

(Ba.sub.vBi.sub.xA.sub.yRE.sub.w).sub.m(Ti.sub.uTM.sub.z)O.sub.3  (1),

wherein, A represents at least one element selected from Na and K, RE represents at least one element selected from Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er;

0.750y≦x≦1.50y  (2),

0.007≦y≦0.125  (3),

0≦(w+z)≦0.010  (4),

v+x+y+w=1  (5),

u+z=1  (6),

0.950≦m≦1.050  (7),

0.001 to 0.055 mol of Ca is contained, and 0.0005 to 0.005 mol of at least one selected from Mg, Al, Fe, Co, Cu and Zn is contained.

The disclosed materials, methods, and apparatus, provide novel ultra-high temperature materials (UHTM) in fibrous forms/structures; such “fibrous materials” can take various forms, such as individual filaments, short-shaped fiber, tows, ropes, wools, textiles, lattices, nano/microstructures, mesostructured materials, and sponge-like materials. At least four important classes of UHTM materials are disclosed in this invention: (1) carbon, doped-carbon and carbon alloy materials, (2) materials within the boron-carbon-nitride-X system, (3) materials within the silicon-carbon-nitride-X system, and (4) highly-refractory materials within the tantalum-hafnium-carbon-nitride-X and tantalum-hafnium-carbon-boron-nitride-X system. All of these material classes offer compounds/mixtures that melt or sublime at temperatures above 1800° C.—and in some cases are among the highest melting point materials known (exceeding 3000° C.). In many embodiments, the synthesis/fabrication is from gaseous, solid, semi-solid, liquid, critical, and supercritical precursor mixtures using one or more low molar mass precursor(s), in combination with one or more high molar mass precursor(s). Methods for controlling the growth, composition, and structures of UHTM materials through control of the thermal diffusion region are disclosed.

A composition for forming a PZT-based piezoelectric film formed of Mn-doped composite metal oxides is provided, the composition including: PZT-based precursors containing metal atoms configuring the composite metal oxides; a diol; and polyvinylpyrrolidone, in which when a metal atom ratio in the composition is shown as Pb:Mn:Zr:Ti, the PZT-based precursors are contained so that a metal atom ratio of Pb is satisfied to be from 1.00 to 1.20, a metal atom ratio of Mn is satisfied to be equal to or greater than 0.002 and less than 0.05, a metal atom ratio of Zr is satisfied to be from 0.40 to 0.55, a metal atom ratio of Ti is satisfied to be from 0.45 to 0.60, and the total of Zr and Ti in a metal atom ratio is 1.

A piezoelectric composition including copper and a complex oxide having a perovskite structure represented by a general formula ABO.sub.3, in which an A site element in the ABO.sub.3 is potassium or potassium and sodium, a B site element in the ABO.sub.3 is niobium or niobium and tantalum, the copper is included in n mol % in terms of a copper element with respect to 1 mol of the complex oxide, and n satisfies 0.100≤n≤1.000.