Ngk Insulators, Inc.

Nkg Insulators, Ltd.

Mitsubishi Motors Corporation

Minoru Matsui

Nobuo Tsuno

Tomonori Takahashi

Takao Soma

Keiji Matsuhiro

Isao Oda

Yuichiro Imanishi

Hiroshi Oikawa

Tadao Ozawa

Naohisa Nakashima

The disclosure relates to a novel arrangement of a combustion chamber for diesel engines, which is defined by an inner wall including a fuel-impinging area formed of a metallic material, and a remaining area which at least partly is formed of a ceramic material or a like heat-resisting material. The arrangement serves to achieve an effective exhaust gas clarification, including the minimization of NOx emission, and to realize increased power output and reduced fuel consumption of the engine.

Combustion chamber for diesel engines

A high density silicon nitride sintered body having a substantially crystallized intergranular phase and an improved mechanical strength at high temperature is produced by firing a molded body of a blend comprising Si.sub.3 N.sub.4, a sintering aid and a crystallization controlling agent selected from at least one compound of Cr, Mn, Co, Ni, Nb and Mo with a specified blending ratio.

Silicon nitride sintered body and a method of producing the same

A silicon carbide sintered member is coated at its surface with zirconia, whereby the heat insulating properties are considerably improved.

Silicon carbide sintered members

A silicon nitride sintered member comprises a silicon nitride sintered body and a zirconia layer coated onto the surface of the silicon nitride sintered body. The zirconia layer is preferably coated onto the surface of the silicon nitride sintered body through plasma spraying. The zirconia-coated silicon nitride sintered member has both high strength at high temperatures and excellent heat insulating property.

Process of preparing zirconia-coated silicon nitride sintered member

Silicon nitride sintered bodies are disclosed herein which each contain an intergranular phase. The intergranular phase contained in the sintered body is crystallized into diopside structure type crystals and apatite structure type crystals. The silicon nitride sintered bodies have excellent density and mechanical strength as well as extremely excellent static fatigue characteristics, and therefore are applicable as various mechanical structural parts such as engine parts, gas turbine parts, etc.

Silicon nitride sintered bodies

Metallizing pastes are disclosed, which contain, as inorganic materials, 15 to 50% by weight of a component to form a glass phase and 50 to 85% by weight of a metallic molybdenum powder. The glass phase essentially consists of 5 to 25% by weight of Al.sub.2 O.sub.3, 35 to 55% by weight of SiO.sub.2 and 30 to 55% by weight of MnO. A process for metallizing ceramic members is also disclosed. The metallizing paste is applied to surfaces of the ceramic member and the dried. The ceramic member with the dried metallizing paste is then fired in a temperature range from 1,200.degree. to 1,400.degree. C. for 0.5 to 10 hours in a mixed gas of hydrogen gas and nitrogen gas in which a ratio in partial pressure between steam and hydrogen, (P.sub.H.sbsb.2.sub.O /P.sub.H.sbsb.2), is adjusted in a range from 10.sup.-6 to 10.sup.0.

Metallizing paste and a process for metallizing ceramic articles by

Zirconia-coated silicon nitride sintered member

A silicon nitride sintered bodies are disclosed, which mainly consist of Si.sub.3 N.sub.4 and contains at least an oxide of a rare earth element and ZrO.sub.2. In the silicon nitride sintered bodies, a J phase solid solution is present in an intergranular phase. The silicon nitride sintered bodies are produced by steps of raw material-formulating, molding and firing. The J phase solution is precipitated in the intergranular phase by temperature-descending step or a reheating step after the firing.

Silicon nitride sintered bodies and a method of manufacturing the same

A turbine rotor unit and a method of producing the same are disclosed. This turbine rotor unit comprises a ceramic rotor, a ceramic shaft integrally united with the ceramic rotor and a metal shaft provided with a cylindrical portion fixing the ceramic shaft therein and is characterized by having a gap between a substantial portion of the inner peripheral surface of the cylinder portion located near the side of the ceramic rotor and the outer surface of the ceramic shaft. Further, the turbine rotor unit is produced by arranging on one end of the metal shaft a cylindrical portion wherein an inner diameter at its opening side is larger than that at the bottom side, inserting the ceramic shaft into the cylindrical portion, and fixing the ceramic shaft to the cylindrical portion at its small diameter side.

Turbine rotor units and method of producing the same

Disclosed herein is a ceramic shape memory element containing zirconia. A ceramic article is also disclosed which contains at least one of tetragonal zirconia and monoclinic zirconia, and is subjected to plastic deformation through phase transformation caused by maintaining the article at a given temperature, and/or imposing a given stress thereupon. Methods of processing and joining the ceramic article by utilizing the shape memory phenomenon peculiar to such a ceramic article are also disclosed.

Ceramic shape memory element

Disclosed herein is a high durability zirconia porcelain which is high in thermal stability and free from degradation phenomena such as profile change and strength reduction, and is characterized in that change in length after the zirconia porcelain being maintained in hot water at 250.degree. C. for 50 hours is not more than 0.05%.

Zirconia porcelain

A metal-ceramic composite article produced by fitting a projection formed on a ceramic member into a hole formed in a metallic member having a hardened region and an unhardened region on its surface such that the ceramic member is monolithically bonded to the metallic member and the deformed region of the metallic member resulting from the fitting is located within its unhardened range, has a high bonding force between the ceramic member and the metallic member and is adapted to be used in engine parts, such as turbocharger rotor, gas turbine rotor and the like, and other structural parts exposed to high temperature or to repeating loads, by utilizing the heat resistance, wear resistance and high strength of the ceramic.

Metal-ceramic composite article and a method of producing the same

Disclosed herein is a metal-ceramic composite article which includes a metallic member made of a precipitation hardenable alloy and a ceramic member, wherein a projection of the ceramic member is fitted into a hole or a through hole formed in the metallic member and the metallic member of the composite article is hardened through precipitation hardening. A process for manufacturing such a metal-ceramic composite article is also disclosed. The manufacturing process includes the steps of: fitting a projection formed at a ceramic member into a hole formed in the metallic member made of a precipitation hardenable alloy in a state in which precipitation-hardening is not carried out to form a metal-ceramic joint body, and subjecting the thus formed metal-ceramic composite body to a precipitation hardening treatment to harden the metallic member.

Metal-ceramic composite article and a process for manufacturing the same

Disclosed herein is an internal combustion engine piston having a metal piston body and a piston cap constituted by a plurality of ceramic pieces and fixed to the top portion of the metal piston body, wherein the piston cap is composed of at least one kind of a ceramic material, at least one of the ceramic pieces is fixed to the metal piston body through fitting or through engagement by way of a metallic piece secured onto said at least one ceramic piece, and the remaining ceramic piece or pieces are fixed onto the metal piston body by means of said at least one ceramic piece. A method for producing an internal combustion engine piston is also disclosed, which method includes steps: forming the piston cap from at least one kind of a ceramic material, forming a fitting projection on at least one of the ceramic pieces constituting the piston cap, fixing said at least one of the ceramic pieces onto the metal piston body through fitting the fitting projection to a through hole or depression formed at the top portion of the metal piston body, and fixing the remaining ceramic piece or pieces onto the metal piston body by means of said at least one of ceramic pieces fixed to the metal piston body.

Growing community of inventors

Nagoya, Japan

Minoru Matsui