Data from manuscript: Assessment of the 7075-T6-aluminum-alloy/microalloyed-dual-phase-steel joint for automotive chassis

The corrosion behavior of a 7075-T6 Aluminum Alloy sample (AA7075-T6) and
a low-Carbon low-Manganese microalloyed dual-phase steel sample (MADPS)
were studied by electrochemical impedance spectroscopy (EIS) and
potentiodynamic polarization (PP). The galvanic corrosion resulting from
their assembly within a dissimilar joint, was studied by the
zero-resistance ammeter technique (ZRA). The tests were conducted at room
temperature and pressure (Mexico City) using an aqueous solution of 3%
NaCl as electrolyte (pH 5.3) and without deaereating the solution. All
tests were repeated more than twice to check the reproducibility.
Electrochemical impedance spectroscopy (EIS) and potentiodynamic
polarization were conducted using a BioLogic VMP3 potentiostat with EC-Lab
software. The samples were pasted to the side of an acrylic cell. Circular
sections of 1 cm2 on top of the samples were cut off from the cell to
allow electrolyte contact. A typical three-electrode cell arrangement was
used, with the samples connected as working electrode (WE), an Ag/AgCl
(3.5 M KCl) electrode as the reference electrode (RE), and a platinum wire
or mesh as counter electrode (CE). The samples were allowed to contact the
electrolyte during 1 h before each electrochemical measurement to allow
open circuit potential (OCP) stabilization. Impedance measurements were
performed in the frequency range from 100 kHz to 10 mHz, with a 10 mV
voltage amplitude from the OCP, acquiring the data at a resolution of 10
points per decade. Potentiodynamic polarization curves were carried out
with a potential scanning rate of 0.5 mV/s from - 250 mV to +250 mV vs.
(Ag/AgCl) to ensure steady-state conditions. The zero-resistance ammeter
(ZRA) technique was conducted using the BioLogic VMP3
potentiostat. The galvanic couple was set in a coplanar
configuration with the samples contacting each other along one of their
sides. The samples were pasted to the bottom of the acrylic cell. The
MADP-steel sample was connected as WE, while the AA was connected as CE,
and an Ag/AgCl (3.8M KCl) was employed as RE (set at a height of 4 mm from
the samples surface). The galvanic current and the galvanic potential were
measured every 0.5 s during 4 h. The galvanic current was further divided
by the electrode area to calculate the galvanic current density.