Characteristics of Thermocouples

character-istics	general	composition	temperature range	suitable application	unsuitable application
thermo-couples
type E	base metal thermocoupleNiCr -CuNi (nickel-chrome/copper-nickel) single wires made of non precious metals	EP-leg: 89-90% nickel, 9-9,5% chrome, 0,5% silicium and iron balance: C, Mn, Nb, Co EN-leg: 55% copper, 45% nickel approx. 0,1%, co balt, iron and manganese	-200°C/+700°C	in pure, oxidizing (air), or neutral atmosphere (inert gases) high resistance against corrosion small thermal conductivit	not sulphuric, reducing or alternately oxidizing, and reducing atmosphereu do not apply in vacuum for a long time
type J	base metal thermocoupleFe - CuNi (iron/copper-nickel) single wires made of non precious metals	JP-leg: 99,5 % iron, approx. 0,25 % manganese, approx. 0,12 % copper, balance: other impurities JN-leg: 55% copper, 45% nickel approx. 0,1%, cobalt, iron, and manganese	-180°C/+700°C	from 0-760°C in vacuum, oxidizing (air), reducing orinert atmosphere (inert gases)	temperatures below 0°C sulphurous atmosphere above +500°C above 760°C only with bigger wire diameters
type K	base thermocoupleNiCr - NiAl (nickel-chrome/ nickel-aluminium) single wires made of non precious metals	KP-leg: 89-90% nickel, 9-9,5% chrome, 0,5 % silicium and iron balance: C, Mn, Nb, Co KN-leg: 95-96% nickel, 1-1,5% silicium, 1-2,3 % aluminium, 1-3,2% manganese, 0,5% cobalt, balance: Fe, Cu, Pb	-270°C/+1372°C	from 250°C-1260°C in pure, oxidizing (air) and neutralatmosphere (inert gases) for higher temperatures bigger wire diameters are recommended	between 250°C up to 600°C not suitable for exact measurements with quick temperature changes not appropriate for a longer time with high temperatures in vacuum do not apply with high temperatures in sulfurous, reducing or alternately oxidizing, and reducing atmoshere without protection do not use in atmosphere favourizing "green mould"
type L	base thermocouple Fe - CuNi (iron/copper-nickel) single wires made of non precious metals	LP-leg: 99,5 % iron, approx. 0,25 % manganese, approx.0,12 % copper, ballance: other impurities LN-leg: 55% copper, 45% nickel, approx.0,1% cobalt, iron, and manganese	0°C/+900°C	from 0°C-760°C in vacuum, oxidizing (air), reducing or inert atmosphere (inert gases) above 500°C bigger wire diameters are recommended	Temperatures below 0°C sulphurous atmosphere above +500°C above 760°C only with bigger wire diameters
type N	base thermocouple NiCrSi - NiSi (nickel-chrome-silicium/nickel-silicium-magnesium) single wires made of non precious metals	NP-leg: 84% nickel, 14-14,4 % chrome, 1,3-1,6% silicium, ballance (not more than 0,1%): Mn, Fe, C, Co NN-leg: 95 % nickel, 4,2-4,6 % silicium, 0,5-1,5 % magnesium, ballance: Fe, Co, Mn, C, (altogether 0,1-0,3%	-270°C/+1300°C	from 300°C-1260°C in pure, oxidizing (air) and neutral atmosphere (inert gases)	do not use with high temperatures in sulphurous, reducing or alternately oxidizing, and reducing atmosphere without protection do not use with high temperatures in vacuum do not use in atmosphere faviourizing "green mould" reducing atmosphere
type R	base thermocouple Pt13%Rh - Pt (platinum 13% rhodium/ platinum) single wires made of platinum and platinum - rhodium alloy	RP-leg: platinum with 99,99% purity with a rhodium alloy (purity 99,98%) 13±0,05% rhodium portion RN-leg: platinum with 99,99% purity	-50°C/+1768,1°C (melting point) recommended: bis +1300°C	pure, oxidizing atmosphere (air), non aggresive (inert-) gases, and short-term in vacuum above +1200°C type B more appropriate	reducing atmosphere umetal gases (for example plomb or zinc) agressive vapours containing arsenic, phosphor or sulphur do never use metal protecting tubes with higher temperatures sensitive against impurities of impure metals
type S	base thermocouple Pt10%Rh - Pt (platinum 10% Rhodium/ platinum) single wires made of platinum and platinum - rhodium alloy	SP-leg: platinum with 99,99% purity with a rhodium alloy (purity 99,98%) 10±0,05% rhodium portion SN-leg: platinum with 99,99% purity	-50°C/+1768,1°C (melting point) recommended: bis +1300°C	pure, oxidizing atmospheres (air), non agressive (inert-) gases, and short-term in vacuum above +1200°C type B more appropriate	reducing atmosphere umetal gases (for example plomb or zinc) agressive vapours containing arsenic, phosphor, or sulphur do never use metal protecting tubes with higher temperatures sensitive against impurities of impure metals
type B	base thermocouple (Pt 30%Rh - Pt 6%Rh platinum -0% rhodium/ platinum-6% rhodium) single wires made of platinum and platinum - rhodium alloy	BP-leg: platinum with 99,99% purity with a rhodium alloy (purity 99,98%) 29,60±0,2% rhodium portion BN-leg: platinum with 99,99% purity with a rhodium alloy (purity 99,98%) 6,12±0,02% rhodium portion	max. +1820°C (melting point) ordinary up to +1700°C	pure, oxidizing atmosphers neutral atmospheres vacuum	reducing atmosphere or such with agressive vapoursor impurities which react with metals of the platinum group, if it is not protected with a non metal protecting tube
type T	base thermocouple Cu - CuNi (copper/copper-nickel) single wires made of non precious metals	TP-leg: 99,95% copper, 0,02-0,07% oxygen, 0,01% impurities TN-leg: 55% copper, 45% nickelapprox. 0,1% cobalt, iron, and manganese	-270°C/+400°C	from -200°C-370°C in vacuum, oxidizing (air), reducing or inert atmosphere (inert gases) with higher temperatures bigger wire diameters are recommended	above +370°C not appropriate in a hydrogen atmosphere not appropriate in radioactive environment
type U	Unedelmetall-base thermocouple Cu - CuNi (copper/copper-nickel) single wires made of non precious metals	UP-leg: 99,95% copper, 0,02-0,07% oxygen, 0,01% impurities UN-leg:55% copper, 45% nickel approx. 0,1% cobalt, iron, and manganese	0°C/+600°C (+400°C)	from -200°C-370°C in vacuum, oxidizing (air), reducing or inert atmosphere (inert gases) with higher temperatures bigger wire diameters are recommended	above +370°C not appropriate in a hydrogen atmosphere not appropriate in radioactive environment