There are 8 common types of thermocouples:

TypeMetal A (+)Metal B (-)Theoretical limitsSeebeck coef.
α (µV/°C) at T°C		Standard errorMin. error
BPlatinum
30% Rhodium		Platinum
6% Rhodium		0 to 1820°C5,96 µv at 600°C0,5%0,25%
ENickel
10% Chrome		Constantan-270 to 1000°C58,67 µV at 0°C1,7% to 0,5%1% to 0,4%
JIronConstantan-210 to 1200°C50,38 µV at 0°C2,2% to 0,75%1,1% to 0,4%
KChromelAlumel-270 to 1372°C39,45 µV at 0°C2,2% to 0,75%1,1% to 0,2%
NNicrosilNisil-270 to 1300°C25,93 µV at 0°C2,2% to 0,75%1,1% to 0,4%
RPlatinum
13% Rhodium		Platinum-50 to 1768°C11,36 µV at 600°C1,5% to 0,25%0,6% to 0,1%
SPlatinum
10% Rhodium		Platinum-50 to 1768°C10,21 µV at 600°C1,5% to 0,25%0,6% to 0,1%
TCopperConstantan-270 to 400°C38,75 µV at 0°C1% to 0,75%0,5% to 0,4%