RepRap: Blog

As ever, I'm constantly on the look out for nice conducting materials. I recently stumbled across a special powdered Nickel. What’s particularly interesting about it is that it is dendritic i.e. the particles are spiky rather than spherical. Essentially this means that when mixed with a polymer, the metal particles are more likely to touch each other so it therefore gives a much lower resistance.

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