The quartz crystal microbalancz has attracted much attention due to its capability to measure small mass changes. In the present work this technique was developed to investigate scale deposit processes and to evaluate scale inhibitor’s efllciency. Experiments were performed on diflkrent water qualities at different temperatures and the inhibiting properties of two phosphonates (HEDP and EDTMP) were compared. The efficiency of these anti-scale additives was tested at different
concentrations on both gold and AISI 1038 steel coated quartz crystals. EDTMP was shown to be a low-effective scale inhibitor in all the experimental conditions (concentration, temperature and nature of the substrate) while HEDP exhibited good pertlormances, keeping the deposited mass at very low values. The influence of the nature of the substrate was also studied: the deposited mass obtained on steel surfaces was higher than on gold surfaces, suggesting a specific effect due to the presence of iron.
Keywords: scale deposits, Electrochemical Quartz Crystal Microbalance, scale inhibitors, HEDP, EDTMP