Abstract: This invention has an object to provide a spark plug exhibiting high withstand voltage characteristics and high strength at high temperature, formed by an alumina-based sintered body prepared with excellent processability and high productivity, and a method for manufacturing the spark plug. This invention relates to a spark plug 1 including an insulator 3, wherein the insulator 3 includes a dense alumina-based sintered body having an average crystal particle diameter of 1.50 ?m or more, and the alumina-based sintered body contains Si, a Group 2 element component containing Ba and a Group 2 element other than those, and a rare earth element component, such that a ratio of a content S of the Si component to a total content of the content S and a content A of the Group 2 element component is 0.60 or more, and a method for manufacturing the spark plug 1 prepared through a grinding-shaping process in which the insulator 3 is ground before burning to shape the same.

Abstract: There are provided a piezoelectric ceramic composition that includes a bismuth layer-structured compound, which contains Na, Bi, Co and Ln (lanthanoide), as a main component and a piezoelectric ceramic composition that includes a compound, which contains Na, Bi, Ti, Co and Ln (lanthanoide) and has a Na0.5Bi4.5Ti4O15 type crystal structure, as a main component, wherein the piezoelectric ceramic composition has an atomic ratio of 0<Ln/(Na+Bi+Ln)?0.04.

Abstract: An object of the invention is to provide a spark plug including an insulator which is difficult to cause breakdown and exhibits higher withstand voltage characteristics. This invention relates to a spark plug 1 including a center electrode 2, an insulator 3 and a grounding electrode 6, wherein the insulator is formed by an alumina-based sintered body which has a theoretical density ratio of 95.

Abstract: According to an aspect of the present invention, there is provided a sintered electroconductive oxide containing a perovskite phase of perovskite-type crystal structure represented by the composition formula: M1aM2bM3cAldCreOf where M1 is at least one of elements of group 3A other than La; M2 is at least one of elements of group 2A; M3 is at least one of elements of groups 4A, 5A, 6A, 7A and 8 other than Cr; and a, b, c, d, e and f satisfy the following conditional expressions: 0.600?a?1.000; 0?b?0.400; 0.150?c<0.600; 0.400?d?0.800; 0<e?0.050; 0<e/(c+e)?0.18; and 2.80?f?3.30. With the use of this conductive oxide sintered body, it becomes possible to carry out proper temperature measurements over the temperature range from a low temperature of ?40° C. to a high temperature of 900° C. or higher.

Abstract: A thermistor element includes a thermistor body and a reduction-resistant coating covering the thermistor body. The thermistor body contains a perovskite phase of perovskite-type crystal structure represented by the composition formula: ABO3 where A is at least one A-site element and B is at least one B-site element. The reduction-resistant coating is formed of a complex oxide containing one or more of the at least one A-site element and one or more of the at least one B-site element.

Abstract: There is provided a piezoelectric ceramic composition that contains Na, Bi, Ti and Co wherein the composition ratio of Na, Bi, Ti and Co in terms of oxides thereof is in the following composition range (1): aNa2O-bBi2O3-cTiO2-dCoO??(1) where a, b, c and d are mole fractions; 0.03?a?0.042; 0.330?b?0.370; 0.580?c?0.620; 0<d?0.017; and a+b+c+d=1.

Abstract: A piezoceramic material according to an embodiment of the present invention has a composition represented by Pbm{Zr1-x-y-zTixSny(Sb1-nNbn)z}O3 where 1.000?m?1.075, 0.470?x<0.490, 0.020?y?0.040, 0<n<1.000 and 0<z?0.025 and a crystallite size of 30 to 39 nm.

Abstract: Disclosed is a ceramic heater capable of preventing failures due to the thermal stress, such as cracks, and corrosion by a calcium component. The ceramic heater has a heating element including at least one substance selected from silicides, nitrides and carbides of molybdenum and silicides, nitrides and carbides of tungsten as a main component, and a base mainly containing silicon nitride in which the heating element is embedded, wherein the base includes: a rare earth element component in an amount from 4 to 25% by mass in terms of an oxide thereof; a silicide of chromium in an amount from 1 to 8% by mass in terms of chromium silicide; and an aluminum component in an amount from 0.02 to 1.0% by mass in terms of aluminum nitride.

Abstract: According to an aspect of the present invention, there is provided a sintered electroconductive oxide containing a perovskite phase of perovskite-type crystal structure represented by the composition formula: M1aM2bM3cAldCreOf where M1 is at least one of elements of group 3A other than La; M2 is at least one of elements of group 2A; M3 is at least one of elements of groups 4A, 5A, 6A, 7A and 8 other than Cr; and a, b, c, d, e and f satisfy the following conditional expressions: 0.600?a?1.000; 0?b?0.400; 0.150?c<0.600; 0.400?d?0.800; 0<e?0.050; 0<e/(c+e)?0.18; and 2.80?f?3.30. With the use of this conductive oxide sintered body, it becomes possible to carry out proper temperature measurements over the temperature range from a low temperature of ?40° C. to a high temperature of 900° C. or higher.

Abstract: A thermistor element includes a thermistor body and a reduction-resistant coating covering the thermistor body. The thermistor body contains a perovskite phase of perovskite-type crystal structure represented by the composition formula: ABO3 where A is at least one A-site element and B is at least one B-site element. The reduction-resistant coating is formed of a complex oxide containing one or more of the at least one A-site element and one or more of the at least one B-site element.

Abstract: Objects of the present invention are to provide a piezoelectric ceramic composition which contains substantially no lead, which exhibits excellent piezoelectric characteristics, and which has high heat durability; and to provide a piezoelectric element including the composition. The piezoelectric ceramic composition contains M1 (a divalent metallic element, or a metallic element combination formally equivalent to a divalent metallic element); M2 (a tetravalent metallic element, or a metallic element combination formally equivalent to a tetravalent metallic element); and M3 (a metallic element of a sintering aid component), wherein, when these metallic elements constitute the formula [(½)aK2O-(½)bNa2O-cM1O-(½)dNb2O5-eM2O2], a, b, c, d, and e in the formula satisfy the following relations: 0<a<0.5, 0<b<0.5, 0<c<0.11, 0.4<d<0.56, 0<e<0.12, 0.4<a+b+c?0.

Abstract: A dielectric material containing at least one of Ca and Sr, Ti, Al, at least one of Nb and Ta, and O, wherein these elements fulfill the following four requirements when represented by a compositional formula, aM1O-bTiO2-(½)cAl2O3-(½)dM22O5 wherein M1 represents the at least one of Ca and Sr; M2 represents the at least one of Nb and Ta; and a, b, c and d represent each a molar ratio, provided that a+b+c+d=1: 0.436<a?0.500; 0.124<b?0.325; 0.054<c?0.150; and 0.170<d<0.346.

Abstract: A ceramic sintered body comprising from 90 to 99.8% by volume of cordierite and from 0.2 to 10% by volume of mullite based on 100% by weight of a total sum of the contents of the cordierite and the mullite, and having a density of 2.48 g/cm3 or more.

Abstract: A dielectric material containing at least one of Ca and Sr, Ti, Al, at least one of Nb and Ta, and O, wherein these elements fulfill the following four requirements when represented by a compositional formula, aMlO-bTiO2-(½)cAl2O3-(½)dM22O5 wherein M1 represents the at least one of Ca and Sr; M2 represents the at least one of Nb and Ta; and a, b, c and d represent each a molar ratio, provided that a+b+c+d=1: 0.436<a?0.500; 0.124<b?0.325; 0.054<c?0.150; and 0.170<d<0.346.

Abstract: A temperature sensor including a thermosensitive element and a ceramic body having a hollow section which surrounds the thermosensitive element airtightly. The thermosensitive element is formed on a heat-sensing surface side of the ceramic body having the hollow section. The hollow section is formed at a position which is shifted to the heat-sensing surface side with respect to the center of the temperature sensor. The ceramic body includes a heat-sensing surface side ceramic layer (1) having the thermosensitive element (4) disposed thereon, a spacer ceramic layer (3) having an aperture, and a substrate ceramic layer (2) serving as a substrate.

Abstract: A sintered alumina ceramic obtained by preparing a raw material powder mixture containing alumina and a Group 3A metal oxide or a Group 3A metal compound which provides a Group 3A metal oxide on heating, and firing said raw material powder mixture. The sintered ceramic contains alumina particles having an average particle diameter of 4.0 &mgr;m or smaller. In the sintered ceramic, the total content of alkali metal elements, alkaline earth metal elements, Si, and Ti as converted to oxides accounts for 0.1 mol or less with respect to 100 mols of alumina, the total peak intensity for the principal peaks for ReAlO3 and Re3Al5O12 (Re: Group 3A metal) amounts to from 1 to 75% of the intensity of the principal peak of alumina as measured by X-ray diffraction, and the relative density is 99.0% or higher with respect to the theoretical density.

Abstract: A ceramic sintered body comprising from 90 to 99.8% by volume of cordierite and from 0.2 to 10% by volume of mullite based on 100% by weight of a total sum of the contents of the cordierite and the mullite, and having a density of 2.48 g/cm3 or more.

Abstract: A sintered alumina ceramic obtained by preparing a raw material powder mixture containing alumina and a Group 3A metal oxide or a Group 3A metal compound which provides a Group 3A metal oxide on heating, and firing said raw material powder mixture. The sintered ceramic contains alumina particles having an average particle diameter of 4.0 &mgr;m or smaller. In the sintered ceramic, the total content of alkali metal elements, alkaline earth metal elements, Si, and Ti as converted to oxides accounts for 0.1 mol or less with respect to 100 mols of alumina, the total peak intensity for the principal peaks for ReAlO3 and Re3Al5O12 (Re: Group 3A metal) amounts to from 1 to 75% of the intensity of the principal peak of alumina as measured by X-ray diffraction, and the relative density is 99.0% or higher with respect to the theoretical density.

Abstract: A temperature sensor including a thermosensitive element and a ceramic body having a hollow section which surrounds the thermosensitive element airtightly. The thermosensitive element is formed on a heat-sensing surface side of the ceramic body having the hollow section. The hollow section is formed at a position which is shifted to the heat-sensing surface side with respect to the center of the temperature sensor. The ceramic body includes a heat-sensing surface side ceramic layer (1) having the thermosensitive element (4) disposed thereon, a spacer ceramic layer (3) having an aperture, and a substrate ceramic layer (2) serving as a substrate.