A MICROSCOPIC STUDY ON CARBON-PASTE ELECTRODES

Scanning electron microscopy has been used for observing the surface o f several types of carbon paste electrodes in order to reveal the role of both pasting liquid and carbon powder on the formation of the carb on paste structure. The effect of pasting liquid was studied using car bon pastes prepared from RW-B multicrystalline graphite powder and eit her liquid tricresyl phosphate or Nujol oil. The influence of carbon p owders was investigated on carbon pastes made of two special carbon po wders with globular particles (Sigradur K or Sigradur G, respectively) and of Nujol. Microscopic observations have shown marked alterations in the structure of the carbon pastes studied either due to different physico-chemical properties of the pasting liquids or in consequence o f specific characteristics of the powdered carbon materials, especiall y of the shape and size distribution of carbon particles. Information resulting from this microscopic study was then compared with conclusio ns of previous voltammetric investigations on the same types of carbon pastes, thus providing a way to characterizing better their overall e lectrochemical behavior.