How to choose platinum rhodium 10 - Platinum rhodium thermocouple?

How to choose platinum rhodium 10 - Platinum rhodium thermocouple? Le - in 1885 Chatelier create platinum rhodium - 10 Platinum-rhodium thermocouple, has been 100 years of history, its function and manufacturing process were discussed in detail. The improved components in this kind of thermocouple anode containing 10% of rhodium platinum rhodium ( Code-named SP) Negative for pure platinum (, Code for SN) 。

the thermocouple is characterized by strong oxidation resistance, thermal power function, suitable for use in succession in the oxidizing and inert atmosphere. Temporary using temperature is 1400 ℃, beyond this temperature, even in the air, pure platinum wire will also caused recrystallization grain bulky. So temporary use temperature limit under 1400 ℃, short-term using temperature is 1600 ℃. In all of the thermocouple, its grade, often used as a specification or as a measurement of low temperature thermocouple, the use of its wide temperature range, good homogeneity and interchangeability.

the defects of S type thermocouple is expensive, wire electrode diameter is very fine, 0. 35 ~ 0. 5毫米) , low mechanical strength; Compared with other thermocouple, its small thermoelectric potential match, thermoelectric emfs rate even for 9 mu V / ℃, so need to display instrument with high sensitivity; Thermocouple is not suitable for this kind of atmosphere in resilience or containing metal vapor under the requirements of use, in particular, should prevent contact with iron, silicon, inorganic substances, such as H2 and CO. Short-term use only under vacuum. Platinum is seen in a not too low temperature recrystallization and grain growth situation, not only reduce the intensity of low temperature, are more likely to trigger a purification, the thermocouple function is not stable. Platinum rhodium - 10 Platinum rhodium thermocouple before dividing LB - 3, now is S.