Abstract: Spark plug with an insulator, a center electrode placed in the insulator, a casing provided on the outside off the insulator and a casing electrode attached to the casing. The center electrode and/or the casing electrode are made using a platinum-nickel fiber composite material consisting of a platinum matrix in which nickel fibers are embedded or of a nickel matrix in which platinum fibers are embedded.

Abstract: Silver-nickel composite for electrical contacts and electrodes, particularly intended for spark plug electrodes. In order to prevent corrosive attack to the nickel components, the silver component consists of a silver alloy which is impervious to oxygen, and the nickel component is comprised of nickel or of a nickel alloy. This facilitates the manufacture of contacts and electrodes which have a long service life.

Abstract: A central electrode for spark plugs of internal-combustion engines, comprising a core of a highly heat-conductive base metallic material which is provided in the region of the firing tip with a precious metal casing consisting of silver or a silver alloy with predominantly silver content. At the boundary surface between the core material and the casing at least one interlayer is provided which is oxygen-impermeable and/or prevents the formation of a eutectic between the core material and the material of the casing.

Abstract: In the manufacture of a formed contact part of a metal alloy, wherein the formed part is shaped in one or more manufacturing operations without the removal of metal to produce a contact element, the improvement which comprises forming from the alloying constituents a composite material in which the alloying constituents are heterogeneously embedded, the composite material being formed into the contact part without the removal of metal and, after forming, heating the contact part so as to convert the composite material into a homogeneous alloy. The process is particularly applicable to silver-palladium alloys where the alloy would not itself be suitable for the forming operation.