The Electrochemical Impedance Spectroscopy (EIS) - Part V: a first screening results to evaluation of Ni release as a preliminary remark of a new European rule for the glass industry.

The first screening results concerning the corrosion behaviour (Ni2+ release) of an industrial Ni-Ag arm series treated with two different galvanic coatings [Ni bright + flash of Au 23kt - Ni bright + flash Gun (Ni-Sn)], and then finished with three different final treatments (a coating of diluted epoxy varnish; a coating of standard epoxy varnish; a coating of standard epoxy varnish spread on an electrophoretic primer) was reported. The samples were analyzed by means of a technique - the Electrochemical Impedance Spectroscopy (EIS) - that gives some detailed indications not only on the corrosion rates, but also on the start and the mechanism of the corrosion process. First results, obtained by applying the EIS technique to a monitoring system meant to optimizing a pass or fail test, seem to be through-and-through promising: notwithstanding the sample immersion on the synthetic swear solution is a too drastic treatment in comparison with the common use of the metallic glass parts - which foresee in any case an occasional and/or preserved contact with the skin - the EIS technique is able to distinguish the sample that release or not Ni2+ below of 0.5 µg/cm² week. Before proposing to standardize the method, the obtained results will require the repeatability and reproducibility evaluation of data obtained until now.