Alliedsignal Inc.

Allied Corporation

Other

Chin-Fong Chang

Santosh K Das

Derek Raybould

Richard L Bye, Jr

Edgar Arnold Leone

Richard Dale Taylor

Lee Randall Franz

Michael S Zedalis

Venkatasubramanian Laxmanan

Alex Kozlov

A wear-resistant electrode tip for a spark plug, and a spark plug which incorporates the wear-resistant tip. The wear-resistant tip includes an alloy of platinum, iridium, and tungsten. Surprisingly, by addition of a small amount of tungsten to platinum-iridium alloy, the wear-resistance of a resultant spark plug is greatly improved. The spark plug electrode tip according to the invention is either spherical or rivet-shaped. During manufacture, the spark plug electrode tip is annealed in an annealing furnace. The annealing furnace is preferably either charged with an inert gas such as argon or nitrogen, or is subjected to a vacuum. The electrode tip is, optionally, further externally coated with platinum or a compatible bonding metal alloy before attachment to the electrode. Subsequent to annealing and, where used, to external coating, the spark plug electrode tip is placed in a welding fixture. The tip is then aligned with a spark plug electrode and is resistance welded thereto. Similar procedures are preferably performed on both the center and side electrodes of the spark plug. The annealed spark plug electrode tips using the novel alloys according to the invention have a high resistance to attack by lead and other corrosive elements typically present in the combustion chambers of internal combustion engines. A preferred method of making a wear-resistant spark plug is also disclosed.

Wear-resistant spark plug electrode tip containing platinum alloys,

A spark plug and method of making same, wherein the spark plug includes a platinum alloy tip portion which takes the form of a rivet or a sphere. The tip portion is annealed in an annealing furnace at a temperature between about 700.degree.-1400.degree. C. for a time between about 5-30 minutes. The annealed tip portion is then resistance welded to an electrode of the spark plug. The annealing provides the tip portion with added resistance to corrosion and attack by lead. Preferred embodiments of the spark plug tip material comprise 80% platinum--20% rhodium; 80% platinum--20% iridium; 96% platinum--4% tungsten; and Pt (bal)-Ir(a)%-W(b)%, where 'a' ranges from about 15 to 19 percent by weight, 'b' ranges from about 1 to 4 percent by weight, and the balance is comprised of platinum and incident impurities, and wherein the sum of iridium and tungsten present ranges from about 16 to 19.

Spark plug tip having platinum based alloys

A spark plug and method of making same, wherein the spark plug includes an iridium alloy tip portion which may take the form of a rivet or a sphere. The tip portion is coated with platinum, annealed and then resistance welded to a nickel-based electrode of the spark plug. The platinum coating helps to prevent cracks at the welding joint which might otherwise occur due to the differing coefficients of thermal expansion of the iridium-based alloy tip portion and the nickel-based alloy electrode. The iridium alloy tip portion is further not susceptible to attack by lead or combustive gases and therefore increases the life of the spark plug significantly.

Spark plug electrode having iridium based sphere and method for

A spark plug electrode wire composed of an iridium-rhodium alloy exhibits improved erosion resistance and enhanced durability in leaded and unleaded fuel environments. The alloy is formed into a wire having high thermal conductivity, low electrical resistivity, good oxidation resistance, good corrosion resistance, good wear resistance. It exhibits desirable work function in pure metals and alloys such as iridium and iridium-rhodium. The wire is inserted into the center electrode of the spark plug and brazed to an Inconel base metal and copper core thereof using a silver-based brazing alloy. After electrical engine dynamometer testing for 200 hours, an improvement in erosion resistance as high as eight fold was observed with an 60% iridium-40% rhodium alloy, when compared to a conventional 90% platinum-10% nickel alloy. The iridium-rhodium spark plug electrode wire can be used to minimize erosion and wear resistance in leaded and unleaded fuel environments.

Spark plug electrode tip for internal combustion engine

A rapidly solidified brazing alloy consists essentially of about 14 to 45 weight percent magnesium and 0 to 10 weight percent of at least one element selected from the group consisting of silicon, bismuth, strontium, lithium, copper, calcium, zinc and tin, the balance being aluminum and incidental impurities. The alloy has a microcrystalline structure containing uniformly distributed intermetallic particles. It has the form of a foil (liquidus temperature &lt;570.degree. C.) and can be used to braze non-heat-treatable rapidly solidified Al-Fe-V-Si alloy foil, sheet, plate, and tubing to produce components such as deicing duct, overduct, radiator, heat exchanger, evaporator, honeycomb panel for elevated temperature applications.

Rapidly solidified aluminum-magnesium base brazing alloys

Magnesium base metal alloy sheet is produced by rolling the rolling stock extruded or forged from a billet at a temperature ranging from 200.degree. C. to 300.degree. C. The billet is consolidated from rapidly solidified magnesium based alloy powder that consists essentially of the formula Mg.sub.bal Al.sub.a Zn.sub.b X.sub.c, wherein X is at least one element selected from the group consisting of manganese, cerium, neodymium, praseodymium, and yttrium, 'a' ranges from about 0 to 15 atom percent, 'b' ranges from about 0 to 4 atom percent, 'c' ranges from about 0.2 to 3 atom percent, the balance being magnesium and incidental impurities, with the proviso that the sum of aluminum and zinc present ranges from about 2 to 15 atom percent. The alloy has a uniform microstructure comprised of fine grain size ranging from 0.2-1.0 .mu.m together with precipitates of magnesium and aluminum containing intermetallic phases of a size less than 0.1 .mu.m. The sheets have a good combination of mechanical strength and ductility and are suitable for military, space, aerospace and automotive application. The sheets can be superplastically formed at temperatures ranging from 275.degree. C. to 300.degree. C. and at strain rates ranging from 10.sup.-1 to 10.sup.-2. The condition which maximizes superplastic ductility is a temperature of 300.degree. C. and a strain rate of 0.1/s. An elongation of 436%, combined with uniform deformation within the gage length, allows fabrication of complex shapes.

Superplastically formed product from rolled magnesium base metal alloy

A low melting (liquidus temperature &lt;570.degree. C.) rapidly solidified brazing alloy consists essentially of about 14 to 52 weight percent germanium, 0 to 10 weight percent of at least one element selected from the group consisting of silicon, magnesium, bismuth, strontium, lithium, copper, calcium, zinc and tin, the balance being aluminum and incidental impurities. The alloy has the form of a foil and can be used to braze non-heat-treatable rapidly solidified Al-Fe-Si-V alloy foil, sheet plate and tubing to components such as deicing duct, overduct, radiator, heat exchanger, evaporator, honeycomb panel for elevated temperature applications.

Rapidly solidified aluminum-germanium base brazing alloys

A low melting (liquidus temperature&lt;570.degree. C.) rapidly solidified brazing alloy consists essentially of about 14 to 52 weight percent germanium, 0 to 10 weight percent of at least one element selected from the group consisting of silicon, magnesium, bismuth, strontium, lithium, copper, calcium, zinc and tin, the balance being aluminum and incidental impurities. The alloy has the form of a foil and can be used to braze non-heat-treatable rapidly solidified Al-Fe-Si-V alloy foil, sheet plate and tubing to components such as deicing duct, overduct, radiator, heat exchanger, evaporator, honeycomb panel for elevated temperature applications.

Rapidly solidified aluminum-germanium base brazing alloys and method for

A magnesium based metal matrix composite is made from rapidly solidified magnesium alloy powder and SiC particulate using liquid suspension coprocessing or mechanical alloying. The composite is suitable for consolidation into bulk shapes having, in combination, high strength, high stiffness, low density, low coefficient of thermal expansion, and high hardness. The composite is suited for uses in such applications as space and missile guidance and navigation and control system precision components where low density, very high specific stiffness and long term dimensional and environmental stability are principal performance criteria.

Method of making high strength, high stiffness, magnesium base metal

High strength, high stiffness rapidly solidified magnesium base metal

A magnesium alloy consists essentially of the formula Mg.sub.bal Al.sub.a Zn.sub.b X.sub.c, wherein X is at least one element selected from the group consisting of manganese, cerium, neodymium, praseodymium, and yttrium, 'a' ranges from about 0 to 15 atom percent, 'b' ranges from about 0 to 4 atom percent, and 'c' ranges from about 0.2 to 3 atom percent, the balance being magnesium and incidental impurities, with the proviso that the sum of aluminum and zinc present ranges from about 2 to 15 atom percent. Second phase particles contained by the alloy are less susceptible to corrosion attack. Articles produced from the alloy have superior corrosion resistance and mechanical properties comparable to those made from commercial magnesium alloys. Such articles are suitable for application as structural members in helicopters, air frames, such as gear box housings, where good corrosion resistance in combination with low density and good strength are required.

Ingot cast magnesium alloys with improved corrosion resistance

Method for superplastic forming of rapidly solidified magnesium base

Magnesium base metal alloy sheet is produced by rolling the rolling stock extruded or forged from a billet at a temperature ranging from 200.degree. C. to 300.degree. C. The billet is consolidated from rapidly solidified magnesium based alloy powder that consists of the formula Mg.sub.bal Al.sub.a Zn.sub.b X.sub.c, wherein X is at least one element selected from the group consisting of manganese, cerium, neodymium, praseodymium, and yttrium, 'a' ranges from about 0 to 15 atom percent, 'b' ranges from about 0 to 4 atom percent, 'c' ranges from about 0.2 to 3 atom percent, the balance being magnesium and incidental impurities, with the proviso that the sum of aluminum and zinc present ranges from about 2 to 15 atom percent. The alloy has a uniform microstructure comprised of fine grain size ranging from 0.2-1.0 .mu.m together with precipitates of magnesium and aluminum containing intermetallic phases of a size less than 0.1 .mu.m. The sheets have a good combination of mechanical strength and ductility and are suitable for military, space, aerospace and automotive application.

Hot rolled sheet of rapidly solidified magnesium base alloy

A complex part composed of rapidly solidified magnesium base metal alloy is produced by superplastic forming at a temperature ranging from 160.degree. C. to 275.degree. C. and at a rate ranging from 0.00021 m/sec to 0.00001 mm/sec, to improve the formability thereof and allow forming to be conducted at lower temperature. The rapidly solidified magnesium based alloy has a composition consisting essentially of the formula Mg.sub.bal Al.sub.a Zn.sub.b X.sub.c, wherein X is at least one element selected from the group consisting of manganese, cerium, neodymium, praseodymium and yttrium, 'a' ranges from 0 to about 15 atom percent, 'b' ranges from 0 to about 4 atom percent and 'c' ranges from about 0.2 to 3 atom percent, the balance being magnesium and incidental impurities, with the proviso that the sum of aluminum and zinc present ranges from about 2 to 15 atom percent. Such an alloy contains fine grain size and finely dispersed magnesium-, aluminum- rare earth intermetallic phases. When formed, the part exhibits good corrosion resistance together with high ultimate tensile strength and good ductility at room temperature, which properties are, in combination, far superior to those of conventional magnesium alloys. The part is suitable for application as a structural member in helicopters, missiles and air frames where good corrosion resistance in combination with high strength and ductility is important.

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Morris Plains, NJ, United States of America

Chin-Fong Chang