Temperature sensors and their manufacture

摘要

A temperature sensor comprises particles of semi-conductor or other material so compressed between a conducting sleeve and a conducting core that there is a solid phase bond between the particles and the core and sleeve but between only some of the particles. The arrangement provides a negative (or positive) temperature coefficient resistor. Materials specified as suitable for the particles are inorganic materials such as Al2O3, BaTiO3 (undoped or doped with La), NaNO2, SiC, Co2O3, CuO, Fe2O3, NiO, V2O5, SrTiO3, PbTiO3, BaZrO3, KNO3, Ge, Si, InSb, GaAs, quartz, glass (e.g. lime glasses, "Vycor," "Pyrex" (Registered Trade Marks) or IR glass comprising Si, As, Se and Ta), steatite and Rochelle Salt or crystalline organic insulators such as sucrose and dextrose. The sleeve and other casing material may consist of steel, Cu, Ag, Al, "Monet," "/sHInconel" (Registered Trade Marks), Mo, Ta, Ni or brass. The device may be produced by packing particles 11 in sleeve 1 between plugs 5 and 7 and compressing by progressive reduction of diameter (by e.g. swaging, drawing, extruding or rolling). The resistive characteristic may comprise a sudden fall in resistance as temperature rises, the breakdown being repeatable, or a steady change with temperature, and may be varied by variation of the applied electric field.