What thermocouple (or other sensor ) I can use for direct measurement of temeprature in gaseous hydrogen under 1000 deg C temeprature. Any type of shielding , is not possible It has to be ver very tiny wire. From what I have found thugsten/tungsten rhenium might be the only option , but I would be really happy if someone who expirienced that issue can give some advice, Thank you!
Marek,
I guess that you've tried optical/infra-red methods?
There is also platinum/rhenium, which doesn't suffer from tungsten's recrystallization problem.
IR is not the case here. There is 500 bar of hydrogen and everything is very small. Only small sensor can do the job. Platinium rhenium I think is easily destroyed with hydrogen its good for oxidizing enviroments.
James , can you plese comment more on this recrystallisation problem of tungsten thermocouple? Thank you
only a suggestion which I am not sure it will work but could be a solution:
Could you use the tungsten TCR in a potentiometric scheme to obtain an information about temperature ? This would be a passive way the other being an active way since it generates a tension. Tungsten has as TCR 0.004403 which leads to important resistance changes for your temperature range.
Marek,
Sure - tungsten is a finicky metal. Cycling it from ambient up to those types of temperatures leads to embrittlement. Let's see if I can find a link:
http://nvlpubs.nist.gov/nistpubs/jres/67C/jresv67Cn4p337_A1b.pdf
First column, last paragraph.
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