1 Introduction .................................................. 5
1.1 Project Background and Objectives ......................... 5
1.2 State of the art .......................................... 6
1.2.1 Commercially Available Chemical Conversion
Coatings ............................................ 6
1.2.2 Review of Published Papers .......................... 9
2 Experimental Phase ........................................... 17
2.1 Materials, preparation of specimens, and treatments ...... 17
2.2 Evaluation of the aluminium alloys samples ............... 17
2.2.1 Surface roughness .................................. 17
2.2.2 Surface electrical resistivity ..................... 18
2.2.3 Thermal cycling tests .............................. 18
2.2.4 Salt spray tests ................................... 18
2.2.5 Scanning electron microscopy and energy
dispersive X-ray spectrometry (SEM/EDS) ............ 19
2.2.6 Chemical conversion coatings procedure ............. 19
3 Results / Discussion ......................................... 21
3.1 Visual inspection ........................................ 21
3.1.1 'As received' ...................................... 21
3.1.2 'As produced' ...................................... 21
3.1.3 After thermal cycling tests ........................ 21
3.1.4 After salt spray tests ............................. 21
3.1.5 After thermal cycling + salt spray tests ........... 21
3.2 Surface roughness ........................................ 29
3.3 Surface electrical resistivity measurements .............. 30
3.4 Surface morphology analysis - Scanning electron
microscopy ............................................... 31
3.4.1 After cleaning with Novaclean A186 ................. 31
3.4.2 After chemical conversion coating treatments ....... 32
3.4.3 After thermal cycling tests ........................ 39
3.4.4 After salt spray tests ............................. 43
3.4.5 After thermal cycling plus salt spray tests ........ 47
3.4.6 Comparison and correlation between Aluminium
alloys and techniques performed .................... 51
4 Conclusions .................................................. 57
5 References ................................................... 59
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