The sensitive material used for conductive electrodes is usually platinum. Platinum black plating is the process of coating a layer of black, fluffy metal platinum on the surface of platinum to reduce polarization effects. The porous platinum black increases the surface area of the electrode, reduces the current density, reduces polarization effects, and reduces capacitance interference.
Platinum black electrodes that are not plated or poorly plated can result in significant measurement errors. Platinum black electrodes should be soaked in distilled water during storage and should not be placed dry. If platinum black electrodes are found to be contaminated or ineffective, they can be immersed in a 10% nitric acid or hydrochloric acid solution for two minutes, then rinsed clean with distilled water before measurement. Platinum black electrodes can also be re electroplated, but plating platinum black requires certain requirements and experience. The quality of the plating black layer has a significant impact on electrode performance.