Most high temperature planar gas sensors use Pt as a substrate heater. My understanding is that Pt has very low resistance and you need a lot of current to force joule heating up to 300C. How possible is it that you can attain that temperature by using just few AA batteries?
That reminds me of artificial muscles where
platin is involved. But this kind doesn't work
with current: alcohol is burnt without flame.
http://www.newscientist.com/article/dn8859-methanolpowered-artificial-muscles-start-to-flex.html
Regards,
Joachim
It is my understanding that its not a Pt bar but instead a very thin wire. Because resistance is a function of the cross sectional area and length, you can get a large power drop over a very thin long wire.
yeah basically its a meandered thin Pt from Pt paste. I used a keithely electrometer 6517A to supply votlage but still cant seem to heat it up
Most people begin to use Pt thin film structure for making the tiny micro minaturized heaters, simply for the reason that it will not oxidize at high temperatures in oxygen, because most other metals which can provide much higher resistivity can be used but they may get oxidised probably.
Secondly patterning of Pt is probably easy, or slight better understood, in comparison to other metals, or metallic alloys. But still you got to use very costly photo-lithographic structure to make these heater structures.
But there are problems which are being discussed in the literatue, these Pt heater structures don't stick well to the substrate, and try to get delaminate, or loose their adhesion after some nos. of heating and cooling cycles.
You are right when the resistance is so low , we need to pump high currents, and this means we have to spend a lot of power to run this tiny heater.
alternate materials probably alloys (Nichrome) can be tried, but one has to figure out how to make the structures (IDT electrodes, meander type structures).
K. Sreenivas
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