Thermometry: from sensitive material to thermoelectric thermotransducer
Date
2005-02-24
Journal Title
Journal ISSN
Volume Title
Publisher
Видавництво Львівської політехніки
Lviv Politechnic Publishing House
Lviv Politechnic Publishing House
Abstract
The hard operation conditions of temperature thermotransducers which involve their thermal cycling require
special attention to the study of processes occurring in structural elements, in particular in thermometric materials. Operation
impacts cause the drift of thermometric characteristics due to the influence of the few factors main of which seem to be the thermo
structural stresses.
Therefore, different kinds of sensitive elements were studied. Since traditional polycrystalline thermoelectrodes of
thermocouples are inherent in the well-known drawback linked with recrystallization, there were investigated the liquid metals as
the thermometric substances, melts, single-crystal materials, and metallic glasses. The need for metal glasses application in
thermometry is substantiated, which allows eliminating thermally activated gradients of internal stresses in thermocouples ensuring
high reproducibility and low drift of their thermo-EMF comparing to traditional materials.
The analysis of sources of the instability of thermocouples’ drift is carried out. It demonstrates the density of heat and
electric flows in stressed thermoelectrodes depends not only on temperature and electric potential gradient but also on the stresses’
gradient. This causes the dependence of thermometric parameters of both poly- and single-crystal substance of thermoelectrodes
on the value and nature of stresses occurring within the operation cycle.
Description
Keywords
Temperature, Thermo-EMP, Thermocouple, Amorphous metal alloy, Measurement error
Citation
Stadnyk B. Thermometry: from sensitive material to thermoelectric thermotransducer / Bohdan Stadnyk, Pylyp Skoropad, Svyatoslav Yatsyshyn // Measuring Equipment and Metrology. — Lviv : Lviv Politechnic Publishing House, 2020. — Vol 81. — No 3. — P. 28–32.