Re: Would gold conductivity electrodes be as good as carbon, platinum black etc?

My name is Bob wrote:

Hi, I want to make a conductivity meter (for salty water) that has to last a long time.

I see a lot of electrodes made out of 'platinum black', carbon or even titanium.

I was wondering if a PCB with two gold plated contacts on it would suffice? It seems to me gold is unreactive, with only a very small AC current between the two contacts it won't corrode will it?

I know I could buy one but I want to make it myself.

Thanks.



You are correct in that gold does not corrode, but be advised that current between electrodes means that some kind of compound gets "plated" on at least one of the electrodes, thereby contaminating them.
Also, the plating on copper traces may not completely cover the copper (especiallyu the edges); that makes for an electrochemical cell right there (possible problems in measurements and electrode lifetime).
.