Platinum rhodium wire is the thermocouple wire thermocouple inside, basically has the following model S, R, B ( 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. S type thermocouple deficiency is thermoelectric potential, thermoelectric potential rate is small, low 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. R type thermocouple deficiency is thermoelectric potential, thermoelectric potential rate is small, low sensitivity and mechanical strength under high temperature to drop, is sensitive to pollution, precious metal materials is expensive, and one-time investment is larger. （ B type thermocouple) Platinum rhodium - 30 Platinum rhodium thermocouple platinum rhodium 30-6 Platinum rhodium thermocouple (6 B type thermocouple) For precious metals thermocouple. Accidentally wire diameter provision of 0. 5 mm, allowable deviation - 0. The positive (015 mm, 英国石油公司(BP) In the name of the chemical composition of platinum rhodium, contain the rhodium is 30%, platinum-based is 70%, the cathode ( BN） For platinum rhodium, rhodium for content 6%, therefore, commonly known as the dual platinum-rhodium thermocouple. The highest use thermocouple temperature is 1600 ℃, short-term use temperature is 1800 ℃. B type thermocouple in the thermocouple series has high accuracy, good stability, test your area wide, long service life, high temperature limit, etc. Suitable for oxidation and inert atmosphere, can also be short term used in vacuum, but does not apply to reducing atmosphere or containing metal or nonmetal steam atmosphere. B type thermocouple is an obvious advantage don't need a compensation for the compensation conductor, because in the range of 0 ~ 50 ℃ and internal potential less than 3 mu V. B type thermocouple deficiency is thermoelectric potential, thermoelectric potential rate is small, low sensitivity and mechanical strength under high temperature to drop, is sensitive to pollution, precious metal materials is expensive, and one-time investment is larger.