Ngk Spark Plug Company, Limited

Minato Ando

Masaaki Ito

Fumio Mizuno

Takashi Kato

Takashi Katoh

Kohji Okada

Jun-ichi Tokumoto

Tsunetoshi Okura

Junichi Tokumoto

Yasuyuki Mizushima

Akemi Kurokawa

Yukito Nakayama

Hideyasu Aoki

An internal liquid for a reference electrode containing lithium chloride (LiCl) and ammonium nitrate (NH.sub.4 NO.sub.3) in a dissolved state at a ratio [NH.sub.4 NO.sub.3 ]/[LiCl].gtoreq. 4. Internal liquid also contains AgCl to saturation for use with an Ag--AgCl internal electrode, and is in a gellated state or impregnated in a highly water-absorbent synthetic resin. It is used in conjunction with a comparison electrode or an internal reference electrode for an ion-selective electrode. Drying up of the internal liquid in the gellated state is minimized so that the function of the internal liquid as a liquid bridge may be displayed for a prolonged period of time. If the ionic concentration of the liquid under examination is changed, liquid potential difference remains substantially unchanged to provide a stable reference electrical potential.

Reference electrode

A concentration measuring method and an apparatus measures the concentration of an objective solvent in a mixed solution by flowing a mixed solution through a tube, transmitting light through the mixed solution as it flows through the tubing and measuring the quantity of light transmitted through the fluid. The concentration of the objective solvent in the mixed solution is measured on the basis of either the quantity of light transmitted, the diameter of a light beam received, or a point of convergence of the light transmitted through the mixed solution. These factors being dependent on the concentration of the objective solvent in the mixed solution.

Method and apparatus for concentration measurement by the quantity,

A method of producing a gelled green compact for a thin sintered body is disclosed. The method comprises by steps (a) adding an acid to a solution of metal alkoxide to produce a sol which has the pH controlled within the range from approximately 2 to approximately 3; (b) adding an acid to the sol to lower the pH of the same; (c) adding an alkali to the sol to increase the pH of the same and control the pH within a range from approximately 1.5 to approximately 3; (d) drying the sol; and (e) molding the sol into a gelled green compact. The gelled green compact has a satisfied plasticity.

Method of producing gelled green compact for thin sintered body

A sintered alumina-based ceramic body exhibiting excellent electrical characteristics, in particular, excellent dielectric power factor and a temperature coefficient of a resonant frequency, which consists essentially of 0.01 to 7 parts by weight of Ta.sub.2 O.sub.5 admixed with 100 parts by weight of an expanded Al.sub.2 O.sub.3 --SnO.sub.2 --TiO.sub.2 ternary base composition (by molar fraction) of:

Alumina-based ceramic composition

A metallizing composition consists of 100 parts by weight of tungsten as a main component, from 2 to 12 parts by weight of Al.sub.2 O.sub.3, from 0.1 to 0.8 parts by weight of Ta.sub.2 O.sub.5, from 0.3 to 1.5 parts by weight of SiO.sub.2, and from 0.1 to 0.5 parts by weight in total of CaO and MgO as an additive.

Metallizing composition on alumina porcelain

A dielectric alumina ceramic body having a constant dielectric loss tangent tan .delta. is obtained by sintering a composition consisting essentially of:

Alumina ceramic body

A low-temperature sinterable ceramic composition comprising 1 to 20% by weight of Al.sub.2 O.sub.3, 15 to 50% by weight of SiO.sub.2, 0 to 5% by weight of MgO, 3 to 18% by weight of CaO, 0 to 5% by weight of TiO.sub.2, 1 to 8% by weight of B.sub.2 O.sub.3, 0 to 2% by weight of Li.sub.2 O, 20 to 80% by weight of at least one of zircon, mullite and spinnel, and 1 to 12% by weight of a fluoride selected from CaF.sub.2, MgF.sub.2, LiF, AlF.sub.3, MnF.sub.2, BaF.sub.2 and SrF.sub.2.

Low-temperature sinterable ceramic composition

A sintered alumina porcelain composition is described consisting of a ternary composition consisting of from 96 to 99 mol % of Al.sub.2 O.sub.3 and the remainder consisting of CaO and TiO.sub.2 present in a CaO/TiO.sub.2 molar ratio of from 0.8/1 to 1.1/1 and SiO.sub.2, wherein based on 100 parts by weight of the ternary Al.sub.2 O.sub.3 --CaO--TiO.sub.2 composition, SiO.sub.2 is present in an amount within the range defined by the area within the straight lines connecting points A-B-C-D-E-F-A in the composition diagram set forth in the attached drawing for describing the relationship between the SiO.sub.2 content and the Al.sub.2 O.sub.3 molar ratio, provided that point A is excluded from the range of the SiO.sub.2 content, with said points having the following locations:

Alumina porcelain compositions

An alumina ceramic composition to provide a low dielectric loss in the high frequency region upon sintering, which consists essentially of: 100 parts by weight of a base composition containing therein Al.sub.2 O.sub.3, CaO and TiO.sub.2 within their respective compositional range; and 0.03 to 3 parts by weight of La.sub.2 O.sub.3. The base composition is within a range A-B-C-D-E-A in the ternary diagram (Figure) in molar fraction:

Alumina ceramic composition

Disclosed are dielectric porcelain materials having compositions falling in the quadrilateral area defined by connecting points A, B, C and D in the ternary diagram of components Al.sub.2 O.sub.3, CaTiO.sub.3 and SrTiO.sub.3 in the drawing. The points A, B, C and D are represented in mol % as follows:

Dielectric porcelain material

An alumina porcelain composition is described, consisting of a main component made of from 96 to 99.5 mol % Al.sub.2 O.sub.3 and from 4 to 0.5 mol % of CaTiO.sub.3, and MgO as an auxiliary component, said MgO being present in an amount of not more than 1 part by weight per 100 parts by weight of the main component.

Alumina porcelain composition

An alumina porcelain composition is described, consisting essentially of from 99.4 to 99.9% by weight Al.sub.2 O.sub.3 and a remainder consisting of SiO.sub.2, CaO, and MgO within a compositional range defined by the straight lines connecting the following points A, B, and C in the weight basis ternary composition diagram set forth in the attached drawing:

A high-alumina ceramic composition is described, having a low dielectric loss in the extremely high frequency range, said composition consisting essentially of Al.sub.2 O.sub.3, SiO.sub.2, and MgO, with the Al.sub.2 O.sub.3 content being in the range of from 99.7 to 99.9% and the SiO.sub.2 /MgO weight ratio being in the range of from 1.0/1 to 0.2/1.

High-alumina ceramic composition

An aluminum porcelain composition, is described, of the ternary Al.sub.2 O.sub.3 --CaO--TiO.sub.2 system, having a compositional range defined by points A, B, C, and D in the composition diagram set forth in the drawing, wherein the points A, B, C, and D represent the following molar fractions of Al.sub.2 O.sub.3, CaO, and TiO.sub.2 :

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Aichi, Japan

Minato Ando