Final Report - Strategic Environmental Research and Development ...

Table 4.7. Adhesion Strength values calculated from BT data for old and new samples batch
coated with acetoacetate.
Adhesion Strength (J/m 2 )
Coating Systems Old Batch New Batch
No Cl/Deox No CC 15.31 3.05
No Cl/Deox No CC 13.03 2.96
No Cl/Deox NCP 18.59 18.71
No Cl/Deox NCP 13.63 19.56
No Cl/Deox TCP 16.41 6.13
No Cl/Deox TCP 13.00 -
No Cl/Deox CCC 20.63 -
No Cl/Deox CCC 20.31 10.65
Cl/Deox No CC 22.65 6.36
Cl/Deox No CC 18.70 7.16
Cl/Deox NCP 9.91 18.71
Cl/Deox NCP 10.67 20.18
Cl/Deox TCP 11.35 13.76
Cl/Deox TCP 11.45 9.33
Cl/Deox CCC 18.59 18.71
Cl/Deox CCC 13.63 19.56
Samples were immersed in DI water at 60°C prior to performing the tape test (ASTM D4541).
Figure 4.36 shows images of the samples following the hot water exposure. All the samples
except for the non-cleaned/non-pretreated sample developed blisters. The blisters ranged from
less than 0.5 mm to 3 mm in diameter. The blisters in the non-cleaned/deoxidized samples
treated with CC were very small ( TCP > No CC CCC. These observations, in terms of the deleterious
effect of cleaning/deoxidizing step, agree with the adhesion strength results of NCP and TCP
samples.
XPS analysis was performed on all of the uncoated samples, and the results of the quantitative
analysis of the spectra are given in Table 4.8. The CCC layer was thick as evidenced by the
absence of an Al peak. Cu was completely removed by TCP and CCC. Also, the Cr present in
the cleaned CCC layer was 31% Cr(VI). This percentage was 35at % when the sample was
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