Ngk Spark Plug Company, Limited

Ngk Spark Co., Ltd.

Ngk Spark Plub Co., Ltd.

Masaya Ito

Noboru Ishida

Katsura Matsubara

Masato Taniguchi

Takaya Yoshikawa

Hiroki Watanabe

Mitsuyoshi Kawamura

Seiji Mori

Katsumi Miyama

Tomoo Tanaka

Yoshihiro Yamamoto

Katsuhisa Yabuta

Kouji Funaki

Makoto Sugimoto

Kuniharu Tanaka

Hisaharu Nishio

Nobuyuki Hotta

Takio Kojima

Kenji Nunome

Shunichi Takagi

Hiroki Nakajima

Hiroyuki Tanabe

Hirohito Ito

Shigeaki Akao

Osamu Suzuki

Toru Shimamori

Hisaharu Nishino

Masato Taniguti

Haruo Yamamori

A ceramic heater in which a damage in a joining portion between a heating portion and a lead portion is suppressed and the reliability is excellent is provided. In a ceramic heater () including: a rod-shaped support () which is made from an insulative ceramic; and a resistor member () including a heating portion () embedded in a tip end part of the support (), and a pair of lead portions () which extend from the heating portion () toward a rear end side of the support (), the heating portion () and the lead portions () are made from the same conductive ceramic.

Ceramic heater, method of producing the same, and glow plug using a ceramic heater

The present invention relates to a ceramic heater which is capable of preventing an electric conduction defect of a heat-generating resistor from being caused by a supplied current, thus being excellent in voltage endurance, and a glow plug containing the ceramic heater. The ceramic heatercontained in the glow plughas an insulative ceramic base materialand the heat-generating resistorembedded in the insulative ceramic base material. The heat-generating resistorhas, as main components, an electrically conductive compound, silicon nitride and a grain boundary amorphous glass phase. The amount of the rare earth element contained in the heat-generating resistor is less than 2% by volume in terms of its oxide and, further, a molar ratio R=(A/A+B) of the mol number A of the amount of the rare earth element in terms of its oxide to a total of the mol number A and a mol number B, which is the amount of excess oxygen in terms of silicon dioxide, is 0.3 or less. By achieving such a constitution, the heat-generating resistor is capable of preventing electric conduction defects and of being excellent in voltage endurance.

Ceramic heater and glow plug having the same

A silicon nitride sintered material containing a silicon nitride component and silicon carbide having an average particle size of 1 &#x3bc;m or less in an amount of at least 1 mass % and less than 4 mass %, based on 100 mass % of the silicon nitride component. The carbide is dispersed in the silicon nitride component, and the silicon nitride sintered material has a thermal expansion coefficient of at least 3.7 ppm/&#xb0; C. between room temperature and 1,000&#xb0; C. The silicon nitride component contains a rare earth element in an amount of 15-25 mass % as reduced to a certain oxide thereof and Cr in an amount of 5-10 mass % as reduced to a certain oxide thereof, and a crystalline phase is present in intergrain regions of the sintered material.

Silicon nitride sintered material and production process thereof

A silicon nitride sintered material containing silicon nitride, a Group 4 through 6 element, a rare earth element, and silicon carbide, characterized in that the amount of the rare earth element as reduced to a certain oxide thereof is 5.7-10.3 mol %; the ratio by mol of subtraction remainder oxygen amount calculated in relation to the oxygen contained in the sintered material, the remainder oxygen amount being expressed in terms of silicon dioxide, to the amount of oxygen contained in the sintered material is at least 0.50 and less than 0.70; a four-component crystalline phase of rare earth element-silicon-oxygen-nitrogen is not present; and the thermal expansion coefficient is at least 3.7 ppm/&deg; C. between room temperature and 1,000&deg; C.

A silicon nitride&mdash;tungsten carbide composite sintered and process for preparing the same which contains silicon nitride and tungsten carbide, and is characterized in that the total in amounts of an entirety of rare earth elements as reduced to certain corresponding oxides thereof, the elements being contained in the sintered material, and excess oxygen as reduced to silicon dioxide is 6-20 mass %; the ratio, on a mol basis, of (the amounts of rare earth elements as reduced to the certain corresponding oxides thereof)/(the amounts of the rare earth elements as reduced to the corresponding oxides thereof&plus;the amount of excess oxygen as reduced to silicon dioxide) is 0.3-0.7; a crystalline phase is present in an intergrain region of the sintered material; and an effective firing temperature range within which a flexural strength of at least 800 MPa is obtained encompasses at least 100 degrees. Also disclosed is a glow plug having a ceramic heater comprising the silicon nitride&mdash;tungsten carbide composite sintered material.

Silicon nitride-tungsten carbide composite sintered material, process for preparing the same and glow plug

A silicon nitride-tungsten carbide composite sintered material which contains silicon nitride and tungsten carbide, and characterized in that in an arbitrary cross-section of the sintered material, the ratio of the area of a tungsten carbide portion to that of the entirety of the cross-section is 20-35%, and a tungsten carbide aggregation portion having a longitudinal length of at least 5 &mgr;m is present in the arbitrary cross-section. The production process includes firing raw material powder containing tungsten carbide powder and two silicon nitride powders having different particle sizes.

Silicon nitride&mdash;tungsten carbide composite sintered material, production process therefor, and glow plug comprising the same

An insulator for spark plug comprises an alumina-based sintered body comprising: Al O as a main component; and at least one component (hereinafter referred to as &ldquo;&bgr; component&rdquo;) selected from the group consisting of Ca component, Sr component and Ba component, wherein the alumina-based sintered body comprises particles comprising a compound comprising the &bgr; component and Al component, the compound having a molar ratio of the Al component to the &bgr; component of 4.5 to 6.7 as calculated in terms of oxides thereof, and has a relative density of 90% or more.

Alumina-based sintered body insulator for spark plugs

A connection device for a ceramic gas sensor element includes a sensor assembly and a ring member. The sensor assembly has a ceramic element with a thickness t, an electrical connection portion formed on a side of the ceramic element, and at least one electrical lead in contact with the electrical connection portion, wherein the sensor assembly defines an outer dimension at a position corresponding to the electrical connection portion. The ring member is disposed around the sensor assembly to hold the at least one electrical lead in contact with the electrical connection portion such that the ring member has an inner dimension at a position corresponding to the connection portion that is smaller than the outer dimension of the sensor element. The ring member defines an axial length L that contacts the sensor assembly such that the thickness t and the axial length L satisfy the relation 0.23&lE;L/t&lE;13.

Connection device for ceramic gas sensor element

This discloses an electronic component of a miniature size to be used as e.g. automobile engine peripheral components, such as an exhaust gas oxygen sensor, a heat sensor, and a heater. More specifically, the invention provides an electronic component integral with a heat resistant terminal that is pressure-fitting or shrink-fitted on a ceramic element of the electronic component. This electronic components shows great mechanical and electrical performance, withstanding the high temperature environment over 400 and up to 800.degree. C. to which the ceramic element of the component required expose. The terminal incorporated in this high temperature electronic component comprises a plurality of metal wire leads that electrically connect to a surface of a bar-like ceramic element, at least two ceramic insulators that surround the leads, and a thermal resistant metal ring that shrink-fits or pressure-fits around the ceramic insulators so that the metal leads press in a radial direction holding the element firmly. The thermal resistant metal ring to be used for this shrink fit or pressure fit is preferably made of an alloy, such as Incoloy 909, Inconel 650, and Waspaloy, and the like, thereby preventing the metal leads from coming off at high temperature. The terminal integrated with the ceramic element by the shrink fitting method according to the invention, minimizes the number of parts, attaining a miniaturization of such high temperature electronic component at a low cost.

Electronic component having terminal connecting leads with a high

A ceramic-metal composite assembly includes an intermediate member made of a material having a thermal expansion efficiency between those of the materials forming a ceramic member and a metallic shaft member. The intermediate member is metallurgically joined to the ceramic member whilst being mechanically joined to the metallic member to constitute a single unit.

Ceramic-metal composite assembly

An Al metal joined body is formed by joining Al metal members of Al or Al alloy or by joining such Al metal member and a member of a dissimilar material. The joined body comprises a first joined member, a second joined member and a brazed joining layer interposed between the two members. The brazed joining layer has a thickness from about 50 .mu.m to about 500 .mu.m and comprises from 0.05% to 14% by weight of Si, from 0.05% to 11% by weight of Cu, from 0.05% to 13% by weight of Zn, from 0.05% to 4% by weight of Mg, and at least 56.5% by weight of Al.

Al metal joined body

A ceramic-metal composite assembly includes an intermediate member made of a material having a thermal expansion efficiency between those of the materials forming a ceramic member and a metallic shaft member. The intermediate member is metallurgically joined to the ceramic member while being mechanically joined to the metallic member to constitute a single unit.

A ultrasonic tool horn for use in ultrasonic machining, welding, etc. has a horn main body made of a heat-treatable aluminum alloy. The aluminum alloy is heat treated so as to be as hard as 100 or more on the Vickers hardness scale. In one embodiment, a thin intermediate layer of a non-heat-treatable aluminum alloy is provided between the horn main body and a ceramic tool attached to a slender end portion of the horn main body.

Ultrasonic tool horn

A ceramic-metal composite assembly includes a ceramic member having a stab shaft and a metallic member having a recess. The ceramic member and the metallic member are joined together by press fit, i.e., by fitting the stab shaft into the recess. The stab shaft and the recess after extraction of the stab shaft from the recess has a set relationship of 50 .mu.m.ltoreq.X-Y.ltoreq.150 .mu.m where X is an outer diameter of the stab shaft and Y is an inner diameter of the recess whilst a surface roughness Rz of the recess in the circumferential direction thereof after extraction of the stab shaft from the recess is 1.5 .mu.m or less.

A ceramic-steel joined body includes a ceramic body of silicon nitride, zirconia, silicon carbide, boron nitride, and alumina. The joined body also includes a steel body which has its surface carburized so that the hardness of the surface is greater than the hardness of the inside of the steel body. The ceramic body and the steel body are thermally joined using a brazing material of Ag--Cu--Ti, Ag--Cu--In--Ti, Ag--Ti, Cu--Ti, Ag--Cu--Ni--Ti, Ag--Cu or Ag--Cu--In.

Growing community of inventors

Aichi, Japan

Masaya Ito