Improvement of the Corrosion Resistance of Aluminium Alloys Applying Diff erent Types of Silanes - Advanced Materials for Agriculture, Food and Environmental Safety - page 50

Table 2.5 Composition of AA2024 sealed with silanes from EDX point analysis
(wt% and a t%).

Element BTSE Bis-amino:VTAS Bis-sulfur silane Bis-amino:

bis-sulfur silane

wt% at% wt% at% Wt% At% Wt% At%

O 47.1 60.5 40.7 53.9 40.3 54.2 38.8 52.5

Mg 0.8 0.7 0.6 0.5 0.7 0.6 0.5 0.4

Al 45.3 34.3 50.6 39.7 41.5 33.0 43.6 35.0

Si 4.2 2.8 5.8 4.4 5.0 3.8 5.4 4.2

S 2.6 1.7 2.3 1.5 12.5 8.4 11.7 7.9

Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00

15

10 min

S wt(%)
Si wt(%)

5 min

12

2 min

9

5 min

10 min

6

2 min

3

0

2%
PSS

5%
PSS

2%
PSS

5%
PSS

2%
PSS

5%
PSS

Figure 2.12 Variation of Si (wt%) and S (wt%) in the case of surface i lm obtained for
conversion of AA 2024 anodized sample with bis-sulfur silane 2% and 5% at dif erent
times: 2 min, 5 min, 10 min.

2.5.3 Electrochemical Impedance Spectroscopy (EIS) Tests

h e electrochemical behaviour of the aluminium oxide layer can be rep-
resented by the equivalent circuits shown in Figure 2.13. h ese circuits
consist of a combination of resistance and constant phase elements (CPE):
R E : electrolyte resistance, R P : porous layer resistance, Q P : CPE parameters