Abstract: A self-diagnostic thermocouple (10) having a first (12), a second (14) and a reference (16) thermoelement enclosed in a sheath (20) filled with an insulator (18) separating the thermoelectric elements from each other and the sheath. The three thermoelements (12,14,16) are joined at a common location to form three separate thermocouple junctions (22) having three distinct electrical outputs as a function of temperature. The reference thermoelement (16) is made from a pure metal or alloy which has stable thermoelectric characteristics. Deterioration of the electrical output of the self-diagnostic thermocouple (10) is capable of being detected by a programed microprocessor (100).

Abstract: A method for making mineral insulated cables in which a mineral powder is purified to remove magnetic particles. The purified mineral powder and at least one wire are fed into a seam-welded metal sheath as it is being formed to produce the mineral insulated cable. The mineral insulated cable may then be drawn and annealed to reduce the diameter of the cable to the desired size.

Abstract: An oxidation-resistant alloy for use in a high-temperature or thermal cycling environment. The alloy comprises a nickel-based matrix having a solid solution of 19-23% chromium and 3-6% aluminum. A self-healing, thermodynamically stable oxide layer is formed upon a surface of the alloy which is exposed to an oxidizing atmosphere over a range of temperatures for extended periods of time. The oxide layer protects the alloy from the oxidizing atmosphere. Additions of calcium and yttrium are made to the matrix to substantially remove or stabilize oxygen and sulfur dissolved in the molten alloy. These additions result in retention of about 0.005-0.05% of calcium and 0.01-0.06% yttrium in the cast alloy. The matrix further includes about 2-8% iron to inhibit nucleation and growth of a "gamma prime" nickel aluminum intermetallic compound which would otherwise adversely harden the alloy and cause local disturbance of a uniform distribution of aluminum. The alloy has a VHN below about 350.

Abstract: A multi-wire self-diagnostic thermocouple having three thermocouple elements enclosed in a sheath and insulated therefrom. The three thermocouple elements are electrically connected to each other to form three thermocouple junctions. An electronic circuit response to the three EMF signals generated by the three thermocouple junctions generates an error signal when the ratio between the three EMF signals differs from predetermined ratios signifying that the calibration of at least one of the three thermocouple elements has changed. In the preferred embodiment, the sheath is a metal sheath and the three thermocouple elements are fused to each other and to the metal sheath.

Abstract: A method for making thermocouple wire from powdered alloys and metals. The metal or alloy is atomized from its liquid state into a powdered state as it leaves a melting vat. The powder is then compacted and cold worked to form thermocouple wire. Different lots of a powdered alloy or a powdered metal may be blended to reduce the calibration error of the resultant thermocouple wire.

Abstract: An electrode material for a spark plug 10 for use in an internal combustion engine. The electrode material includes a core 20 having a high thermal conductivity for reducing the temperature of the spark plug 10 by thermally conducting heat away from the spark plug gap to a cooler part of the engine. The core 20 extends continuously from an arcing surface at an end of a spark plug electrode to the cooler part of the engine. Surrounding the core 20 is a cladding layer 22 for resisting corrosion when exposed to high temperatures caused by arcing.