Abstract: 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.

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

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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%.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A highly dense Si.sub.3 N.sub.4 sintered body having a substantially crystalline intergranular phase, which has an improved mechanical strength at high temperatures and excellent static fatigue properties so as to be particularly useful for high temperature structural components or parts, is produced by sintering a molded body of a blend comprising Si.sub.3 N.sub.4, Y-, Mg- and Ce-compounds with a specified composition range.

Abstract: A silicon nitride sintered body essentially consisting of compounds of Sr, Mg, Ce, Zr and Al in amounts of from 0.1 to 18% by weight when calculated as SrO, from 0.2 to 25% by weight when calculated as MgO, from 0.1 to 20% by weight when calculated as CeO.sub.2, from 0.1 to 15% by weight when calculated as ZrO.sub.2 and from 1 to 20% by weight when calculated as Al.sub.2 O.sub.3, respectively, and the balance being silicon nitride. A method of manufacturing the silicon nitride sintered body is also disclosed. The silicon nitride sintered body has a low thermal conductivity while high mechanical strength and high fracture toughness being maintained.

Abstract: An engine part and a method of producing the same are disclosed. The engine part includes a ceramic member, a metallic member secured to the ceramic member, and a metallic engine part body fixed to the metallic member, wherein the outer peripheral portion of the metallic member has a diameter smaller than the outer diameter of the ceramic member and is provided at one end facing the ceramic member with an annular notch. The engine part is produced by securing the ceramic member to the metallic member through fitting or joining and then fixing the metallic member to the metallic engine part body through fitting or screwing.

Abstract: Disclosed herein is an internal combustion engine piston comprising a piston cap formed from a plurality of ceramic pieces, and a metal piston body, the piston cap being fixed to the top portion of the metal piston body, wherein the piston cap is made of one or more types of ceramic materials, and the ceramic pieces constituting the ceramic cap and the metal piston body are bonded together through a metallized layer coated onto the ceramic pieces and a metal-plated layer coated onto the metallized layer in such a manner that the bonding area between the ceramic piece or pieces and the metal piston body may be larger at a top central portion of the metal piston body than that between the ceramic piece or pieces and the metal piston body at another portion thereof. Also disclosed is a method of producing the same.

Abstract: An apparatus for manufacturing electrical harnesses, the apparatus comprising a wire feed path extending horizontally and axially of the apparatus, a connector attaching device located alongside the wire feed path. The attaching device includes a punch and a die to press the wires into the connectors, and a cutter located adjacent to the punch and die such that the cutter is operated independently of the punch and die. A wire measuring and feeding device is reciprocally movable along the wire feed path, with the wire measuring and feeding device including an intermittently movable chuck enabling the connected-attached wires to be pulled to a desired length. A connector selecting and supplying device enables the connectors having a desired number of poles to be selected from connectors and supplied onto the die. A wire selecting and supplying device includes a chuck for selecting the wires which correspond to the selected connectors and supplying the selected wires to the connector attaching device.

Abstract: Silicon nitride sintered bodies having particularly excellent strength and creep resistance at high temperature, in which a total amount of MgO and Al.sub.2 O.sub.3 is more than 7% by weight and not more than 30% by weight and a weight ratio of MgO/Al.sub.2 O.sub.3 is 5-15 and the remainder is mainly Si.sub.3 N.sub.4 and at least one of magnesium sialon crystal represented by the general formula Mg.sub.x/2 Si.sub.6-y+x/2 Al.sub.y-x O.sub.y N.sub.8-y (0<x.ltoreq.y<8, preferably 0.9.ltoreq.x/y) and forsterite crystal represented by the formula Mg.sub.2 SiO.sub.4 is contained as a second phase in addition to the main crystal of Si.sub.3 N.sub.4, are produced by mixing a raw material powder of silicon nitride containing not greater than 2% by weight of oxygen with MgO and Al.sub.2 O.sub.3 so that a total amount of MgO and Al.sub.2 O.sub.3 is from 7% by weight to 30% by weight and a weight ratio of MgO/Al.sub.2 O.sub.3 is 5-15, and firing the resulting mixture at a temperature of 1,650.degree.-1,850.degree.

Abstract: A wire length varying device for an apparatus for making electrical harnesses, with the device comprising a tension pulley unit located on a wire supply path. The tension pulley unit constantly urges the individual wires to return in a counterflow direction. A return preventive device selectively stops the wires from returning under an urging provided by a moving chuck, thereby enabling the stopped wires to slacken by the respective selected lengths. Thus, the lengths of the connector-free terminal end portions of the wires are differentiated as desired.

Abstract: Disclosed herein is a zirconia porcelain which includes 1.5-5 mol % of yttrium oxide, 1-5.5 mol % of cerium oxide and the balance being substantially zirconium oxide. Disclosed herein also is a method of producing a zirconia porcelain, which includes the steps of preparing a mixed powder including 1.5-5 mol % of yttrium oxide, 1-5.5 mol % of cerium oxide and the balance being substantially zirconium oxide having an average particle size of less than 1.5 .mu.m when measured according to an air permeation method, shaping the mixed powder into a molding, and firing the molding thus at a temperature of 1,100.degree. C.-1,700.degree. C.

Abstract: An engine part comprises a plurality of ceramic members overlaid one on the other and including at least a first ceramic member with a front surface to be in contact with hot gas and a second ceramic member arranged behind the first member, each of the first member and the second member has a mechanical strength of more than 20 kg/mm.sup.2.

Abstract: The disclosed polycrystalline transparent sintered body contains Al.sub.2 O.sub.3 and MgO at a molar ratio of (0.54:0.46) to (0.58:0.42) and has in-line transmittance of more than 77% for 1 mm thickness at a light wavelength of 0.6 .mu.m, which sintered body is produced by preparing fine spinel powder through hydrolysis of an isopropanol solution of aluminum isopropoxide and magnesium isopropoxide, forming a shaped body from the powder, and sintering the shaped body.

Abstract: Highly densified silicon nitride sintered bodies having excellent mechanical strength and oxidation resistance consist essentially of Si.sub.3 N.sub.4 and contain Y, Mg and Zr, in which a content of Si.sub.3 N.sub.4 is 95-70% by weight, a content of yttrium is 15-2% by weight calculated as Y.sub.2 O.sub.3, a content of magnesium is 15-0.5% by weight calculated as MgO and a content of zirconium is 13-0.5% by weight calculated as ZrO.sub.2 and are produced by forming a mixed raw powder consisting of 95-70% by weight of silicon nitride raw powder, yttrium compound of 15-2% by weight calculated as Y.sub.2 O.sub.3, magnesium compound of 15-0.5% by weight calculated as MgO and zirconium compound of 13-0.5% by weight calculated as ZrO.sub.2 into a shaped body, said yttrium compound, magnesium compound and zirconium compound being sintering aids, and firing the shaped body at a temperature of 1,650.degree.-1,800.degree. C. under ambient pressure in a nitrogen or an inert gas atmosphere.