Testing of graphite paste properties for thick film sensors

The miniature electrochemical sensors can be produced by thick film technology. The optimal properties of thick film electrode materials are main problems of sensors design. The optimization of graphite paste for TFT chemical sensor properties is discussed. The commercial TFT graphite pastes, which are used for common application, are cheap and easily producible, but they are not efficient for electrochemical measurement. These pastes have insufficient sensitivity and they have other bad properties. Graphite pastes, which were designed for special chemical analysis, are technically known, but these pastes are not workable by screen-printing. The goal of this work is first step in rheologic properties addition to graphite electrochemical pastes. This ensures the pastes printability that will enable the reproducible mass production. The graphite powder mixed with paraffin is the basic component of common chemical graphite pastes. There were examined different properties of these pastes in dependence on graphite powder and binding material content in this work. The measurement was made in standard electrochemical couple of potassium ferrocyanide-ferricyanide.