Thermocouple Type MaterialMagnetic ASTM Color Coding IEC Color Coding
J Iron
Constantan
Yes
No
White
Red
White
Black
T Copper
Constantan
No
No
Blue
Red
White
Brown
K Chromel
Alumel
No
No
Yellow
Red
White
Green
E Chromel/ConstantanNo
No
Purple
Red
White
Violet
P PlatinelN/A N/A N/A
S Platinum 10% Rhodium
Pure Platinum
No
No
Black
Red
White
Orange
R Platinum 13% Rhodium
Pure Platinum
No
No
Black
Red
white
Orange
B Platinum 30% Rhodium
Platinum 6% Rhodium
No
No
Grey
Red
White
Grey
N Nicrosil/NisilNo
Slightly
Orange
Red
White
Pink
C Tungsten 5% Rhenium/ Tungsten 26% RheniumNo
No
White
Red
N/A
Material Description Used With Maximum Temperature
Alumina  Aluminum Oxide Ceramic Noble Metal Thermocouples 3400°F (1870°C)
Mullite Alumina and Silica (Silicon Carbide) Base Metal Thermocouples 3100°F (1700°C)