Thermocouples from electrodeposited submicrometer wires prepared by electrochemical step edge decoration

We describe the preparation of three types of silver/nickel thermocouples (TCs) based upon electrodeposited wires with diameters at, or just below, 1.0 mu m: Type 1-wire/thin film TCs consisting of an electrodeposited submicrometer diameter wire and an evaporated metal thin film; Type 2-wire-wire TCs consisting of end-butted and electrochemically welded silver and nickel submicrometer wires; Type 3-wire-wire TCs for which the silver wires were electrochemically etched prior to the electrodeposition of the nickel wires. The metal wires in all devices were prepared using the electrochemical step edge decoration method. The properties of these TCs for measuring temperature in the range from ambient to 110 degrees C were evaluated. Output voltage, V-TC versus temperature was linear for these devices yielding Seebeck coefficients of 19-22 mu V/degrees C-within 95% of the expected bulk value. Temperature excursions across a 90 degrees C range caused no measurable hysteresis in V-TC for these devices. All three types of devices retained the ability to accurately measure temperature for months after exposure to ambient laboratory air. The response times for these TCs were measured using two different laser heating methods.