What is the difference between S type thermocouple and R type thermocouple _ instrument

Mainly is the difference between the thermocouple wire thermocouple index number ( S type thermocouple) Platinum rhodium - 10 Platinum thermocouple platinum rhodium - 10 Platinum thermocouple ( S type thermocouple) For precious metals thermocouple. Accidentally wire diameter provision of 0. 5 mm, allowable deviation - 0. The positive (015 mm, SP） In the name of the chemical composition of platinum rhodium, contain the rhodium is 10%, platinum-based is 90%, the cathode ( SN) For pure platinum, commonly known as single platinum-rhodium thermocouple. The temperature is 1300 ℃, the long-term use of thermocouple short-term use temperature is 1600 ℃. S type thermocouple in the thermocouple series has high accuracy, good stability, test your area wide, long service life, etc. Its physical and chemical performance is good, the thermoelectric potential stability and oxidation resistance at high temperature performance is good, suitable for oxidizing and inert atmosphere. Because of S type thermocouple has excellent comprehensive performance, in line with the use of S type thermocouple temperature scale, for a long time as a scale interpolation instruments, S type thermocouple deficiency is thermoelectric potential, thermoelectric potential rate is smaller, sensitivity and mechanical strength under high temperature to drop, is sensitive to pollution, precious metal materials is expensive, and one-time investment is larger. （ R type thermocouple) Platinum rhodium - 13 Platinum thermocouple platinum rhodium - 13 Platinum thermocouple ( R type thermocouple) For precious metals thermocouple. Accidentally wire diameter provision of 0. 5 mm, allowable deviation - 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, long-term use of temperature is 1300 ℃, short-term use temperature is 1600 ℃. R type thermocouple in the thermocouple series has high accuracy, good stability, test your area wide, long service life, etc. Its physical and chemical performance is good, the thermoelectric potential stability and oxidation resistance at high temperature is good, suitable for oxidizing and inert atmosphere. Due to the comprehensive performance of R type thermocouple and S type thermocouple, has been difficult to promote in our country, in addition to imported equipment on temperature measurement has been employed, the inner temperature is used rarely. Between 1967 and 1971, the British NPL, the United States and Canada NBS NRC three major research institute conducted a research cooperation, the result shows that the stability of the R type thermocouple and reproducibility is better than S type thermocouple are, our country has yet to conduct the research.