Wednesday, January 26, 2011
Conductive pastes take 453
Apparently this stuff is typically used making conductive paints, so its readily available. I managed to get some filamentary powder thats about 2.35um in cross section and 15um long . In small quantities this costs about £95/kg
A colleague and I crudely made a thin film that measures 100x100x1mm out of this powder mixed with liquid latex in a 1:1 ratio in terms of weight. The paste seemed sufficiently viscous that we could extrude it with a paste extruder. We embedded 9 electrodes in the film so that we could get repeatable readings. The total resistance between opposite electrodes came in at 0.8ohms, which is about a 9cm length spanning the film. I guess this is sufficiently low to be useful for a lot of low current applications.
Labels: nickel, paste, reprappable electronics
I've just cut a small strip of the film.
The cross section is about 1.3x1.3mm and its about 18mm in length. The resistance came in at 9.5ohms
I reckon this comes to a resistivity of 8.9 x 10-4 ohm.
Given that we could still up the concentration of the nickel (the sample above wasn't saturated) a bit. I'm still hopeful.
Carbonyl iron is used in some paint applications, but it's not conductive enough really. Nickel carbonyl is relatively dangerous stuff - and fairly explosive without the proper shielding gas.
Powdered nickel would be fairly easy to deal with and fairly conductive as well (probably not as nice as graphite.)
The health and safety data sheet for the stuff I have is available here:
The powder I am using is just a dendritic nickel. It is is however made from Nickel carbonyl gas at high pressures.
Try reading this article it's related to the type of paste your are making.