Environmental Engineering Reference
In-Depth Information
silane:VTAS, BTSE, bis-sulfur silane, bis-amino silane:bis-sulfur silane),
and another part only treated with conversion coatings based on bis-
sulphur silane without HTS sealing, in order to be sure to elucidate the
best corrosion protection on AA 2024 by the application of silanes. h e
procedures applied are simple (which is an advantage too): the anodized
samples (with and without HTS) were dipped into the silane solutions for
5 minutes at room temperatures. h e silane-treated samples were dried at
100
°
C for 5 minutes. Both times were optimized.
2.4 Surface Analytics
Contact angles with deionized water (DI water), Diiodmethane and
Ethylene glycol have been measured with a Krüss DSA10 MK2 drop shape
analyzer.
h e SEM investigations were performed using a Philips XL30 FEG
ESEM environmental scanning electron microscope for characterization
of nonconductive specimens, equipped with EDX for element analysis.
A FEI Quanta 200 3D, equipped with FIB (focused ion beam), was used
for preparing (ion milling) and characterization of cross-sections through
the oxide layer, determination of layer thickness, surface topography and
structure, elementary composition and depth proi ling (EDX), phase anal-
ysis, identii cation of segregations and inclusions.
h e apparatus for the Salt Spray Test consists of a closed testing cham-
ber, where a salted solution containing 50 g/L sodium chloride is atomized
(converted to an aerosol) by forcing the solution through a i ne nozzle. h us
a corrosive environment of sodium-chloride-containing fog is achieved so
that parts exposed have to face a severe corrosive atmosphere. Tests have
been previously performed in a chamber from Weiss Technik Type SC 450
according to DIN EN ISO 9227.
For IR studies an Equinox-55 (Bruker) equipped with a Golden Gate
ATR-unit (ATR: attenuated total rel ection where spectral information is
gained by total rel ection of the IR beam on the surface of the sample) was
used. h e typical penetration depth of the FTIR beam into the surface in
this experimental set-up is 0.5 to 2 μm. h e number of scans was 10 and
baseline correction was also made.
Electrochemical impedance spectroscopy measurements ( EIS ) were
realized to monitor the corrosion performance of the silane-treated AA
2024-T3 anodized with TSA as a function of immersion time in a 1%
NaCl solution. h e EIS measurements were carried out using a Zahner
IM6 electrochemical workstation. h e measured frequency range was
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