An electrochemical method for testing the scaling susceptibility of insulating materials

Calcium carbonate scale was precipitated from a hard water onto the surface of insulating material by a simple electrochemical technique, which consis ts of increasing the local pH by the electrochemical reduction of dissolved oxygen. When the polarizing electrode is a gauze metal wire, the surface d ensity of nuclei is homogeneous, and the density of nucleation sites is wel l representative of the scaling susceptibility of the tested material. It i s shown, for example, that the scaling susceptibility of polytetrafluoroeth elyne is much lower than for other plastic materials. The crystal variety o f the calcium carbonate nuclei is also correlated to the activity of nuclea tion sites. This original device can be used to perform comparative tests o f all kinds of insulating materials, surface coatings, or surface treatment s. (C) 2001 The Electrochemical Society.