Measurement research for pitting potential of aluminium alloy with chromate passivation layers

Pitting-induced hydrogen embrittlement of magnesium- aluminium alloy

In this study, the pitting corrosion susceptibility and its role on the hydrogen embrittlement behavior of AZ80 magnesium alloy were studied using slow strain rate testing (SSRT), electrochemical technique and immersion test method. The electrochemical and immersion tests in chloride-containing solution revealed severe pitting corrosion in the alloy. The SSRT results of the alloy under continuo...

CORROSION BEHAVIOUR OF A 2219 ALUMINIUM ALLOY TREATED WITH A CHROMATE CONVERSION COATING EXPOSED TO A 3.5 % NaCl SOLUTION

This study investigates the formation of a chromate conversion coating at Al-Cu-Fe-Mn intermetallic sites of an Al2219 alloy and the corrosion initiation at these sites in a 3.5 % NaCl solution, using SEM, AES and EDX. Changes in the surface chemistry were monitored after progressive exposures to the solution up to 42 hours. The coating was found to be thinner and more defective on the intermet...

The binding of phosphonic acids at aluminium oxide surfaces and correlation with passivation of aluminium flake.

Measurements of adsorption isotherms of a series of thirteen mono- and di-phosphonic acids have shown that these bind strongly to the surface of high surface area aluminium trihydroxide. The incorporation of such phosphonates into a suspension of aluminium flake in an aqueous medium, modelling the continuous phase of a water-based paint, greatly suppresses the evolution of hydrogen. Whilst stro...

Positron Lifetime Measurements of Subsurface Region in Aluminium Alloy and Aluminium Alloy Composite after Dry Sliding

This paper presents positron lifetime studies of the subsurface region of AK12 aluminium alloy and Al2O3-particle-reinforced AK12 aluminium alloy composite after sliding against steel in the pin-on-disc machine. The defect depth profile detected in the AK12 alloy extended up to 300 μm but for the composite AK12 the range of this profile was significantly shortened to less than ∼ 90 μm. The posi...

Characterization of Dielectric Layers for Passivation of 4H-SiC Devices