Final Report - Strategic Environmental Research and Development ...

Figure 1.38.
Figure 1.39.
Figure 1.40.
Figure 1.41.
Figure 2.1.
Figure 2.2.
(A) Polarization resistance (R p ) and (B) pit density vs. time profiles
recorded during the full immersion of TCP-coated AA2024, 6061 and
7075 in air-saturated 0.5M Na 2 SO 4 at room temperature.
Pit density vs. time profiles recorded during the full immersion of TCPcoated
and bare AA2024, 6061 and 7075 in air-saturated 0.5M NaCl at
room temperature.
Raman spectra recorded at (a) an Fe-rich intermetallic site and (b) the
terrace near but outside the pit on the TCP-coated AA6061, (c) a Curich
intermetallic site and (d) the terrace outside the pit on the coated
AA7075, after full immersion in air-saturated 0.5M NaCl for 15 days.
Spectra for (e) the Cr(III)/Cr(VI) mixed oxide and (f) the Al(III)/Cr(VI)
mixed oxide (pH 7.40) are also shown for identification
Cr(VI) peak intensity vs. time for the three TCP-coated alloys that were
immersed in the air-saturated 0.5M NaCl for about 30 days. Spectra
were recorded on the terrace near the pits.
Naturally aerated polarization curves for AA2024-T3 in 0.1 M NaCl
solution at varying Na 2 MoO 4 concentrations.
Evolution of (a) polarization resistance and (b) capacitance with time for
AA2024-T3 in chloride solution with and without 125 mM Na 2 MoO 4 .
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Figure 2.3. SEM/EDS after 2 day exposure in 0.1 M NaCl solution containing 125
mM MoO 4 -2 .
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Figure 2.4.
The Mo 3d spectra for a sample exposed to 0.1 M NaCl solution
containing 125 mM Na 2 MoO 4 .
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Figure 2.5. Chronoamperometry in aerated 0.1 M NaCl at E app = -900 mV SCE. 66
Figure 2.6. Mo 3d spectra after MoO 4 2- injection at fixed potential of -900 mV SCE. 66
Figure 2.7.
Polarization curves showing the effect of oxygen on inhibition
performance.
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Figure 2.8. Polarization curves in 0.1 M NaCl solution with and without Na 2 MoO 4
at pH 5.
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Figure 2.9.
(a) Polarization curves in naturally aerated conditions at varying
Na 2 SiO 3 concentrations (b) Changes in E ocp , E pit , and E rp with
concentration.
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