R platinum-rhodium thermocouple is introduced in detail

R platinum-rhodium thermocouple detail platinum rhodium - 13 Platinum rhodium thermocouple ( R type thermocouple) For precious metals thermocouple. Rules of wire diameter of 0. 5 mm, allow to - 0. The positive (015 mm, RP) In the name of the chemical composition of platinum rhodium, contain the rhodium is 13%, platinum-based is 87%, the cathode ( RN） For pure platinum, temporary using temperature is 1300 ℃, short-term using temperature is 1600 ℃. R type thermocouple has measured in thermocouple series [area wide, degree, stability, long life and other advantages. Its chemical and physical function is good, the thermoelectric potential stability and good antioxidant function at low temperatures, suitable in inert and oxidizing atmosphere. As a result of the comprehensive function of the R type thermocouple and S type thermocouple are similar, continuously is difficult to implement in our country, in addition to the temperature measurement is used on export equipment, its temperature measurement is seldom used. Between 1967 and 1971, the British NPL, the United States and Canada NBS NRC three discusses organization implemented a collaborative discussion, the result indicated, the stability of the R type thermocouple and the repeatability is better than S type thermocouple are, at present not yet on this aspect of the discussion. R platinum-rhodium thermocouple is enough thermoelectric potential rate is small, low sensitive to read, low temperature drop, mechanical strength is sensitive to purify.