| Type |
Marker |
Graduation |
Material |
Temperature measuring rang℃ |
Performance characteristics |
| New |
Old |
Advantages |
Disadvantages |
| Thermocouple |
K |
N |
K |
NiCr-NiSi |
-40~1200 |
Good linearity of thermoelectric force,good stability, good oxidation resistance,it is the most widely used temperature measuring element. |
It is not applicable to reducing atmosphere,which is affected by changes of aging and the changes of short - range ordered structure. |
| N |
M |
N |
NiCrSi-NiSi |
-40~1250 |
It has all the advantages of K-type thermocouple，the effect of short - range ordered structure change is small. |
It is not applicable to reducing atmosphere,which is affected by changes of aging. |
| E |
E |
E |
NiCr-Constantan |
-40~900 |
In the existing thermocouple, the thermoelectric force is the highest, the sensitivity is high, and the two poles are non magnetic. |
It is not applicable to reducing atmosphere, with low thermal conductivity and micro hysteresis phenomenon. |
| J |
F |
J |
Fe-Constantan |
-40~750 |
It can be used in reducing atmosphere, and the thermoelectric force is higher than K. |
Iron is easy to rust, thermoelectric characteristics drift is large. |
| T |
C |
T |
Cu-Constantan |
-40~350 |
It can be used in reducing atmosphere, good linearity of thermoelectric force,good low temperature characteristics,Good stability. |
Low operating temperature,the copper of positive electrode is easy to oxidize, and the thermal conduction error is large. |
| S |
P |
S |
PtRh10-Pt |
0~1600 |
It is applicable to oxidizing atmosphere, and can be used in vacuum for a short time. High precision, good stability, not affected by aging changes, oxidation resistance and chemical resistance , can be used as standard thermocouple. |
It is not applicable to reducing atmosphere（Especially H2, metal vapor）and vacuum environment，the price is high, the sensitivity is low, and the linearity of thermoelectric force is not good. |
| B |
R |
B |
PtRh30-PtRh6 |
600~1700 |
Applicable to more than 1000 ℃, thermoelectric force is smaller,can need not compensating lead wire, oxidation resistance, chemical corrosion resistance. |
It can not be used below 600 ℃,the sensitivity is low, and the linearity of thermoelectric force is not good. |
