PROCESS FOR MANUFACTURING PLATINUM TEMPERATURE-MEASURING RESISTANCE ELEMENT

摘要

[PROBLEMS] To provide a process for manufacturing a platinum temperature-measuring resistance element being stable with a less resistance value variation over service temperature range through clarification of a quantitative mechanism of resistance value variation with respect to the oxidation/reduction of platinum resistance wire and through application thereof. [MEANS FOR SOLVING PROBLEMS] The process comprises the step (S1) of preparing a thermosensitive part having a portion to be sealed coated with a glaze; the step (S2) of placing a pre-sealing element on a tray (4) and inserting the same in a chamber (2); the step (S3) of enclosing a purge gas containing an inert gas and oxygen in the chamber (2); the step (S4) of raising the internal temperature of the chamber to a region in which the platinum is in reduced form at a partial pressure of oxygen in the purge gas as determined from platinum oxide formation free energy; the step (S5) of replacing the purge gas with an inert gas wherein oxygen is 1 kPa or below; and the step (S6) of under the replaced condition, rapidly heating the furnace interior (interior of the chamber (2)) to a frit melting temperature by means of a lamp heating unit (6) to thereby seal the portion to be sealed of the thermosensitive part.