P. Casajús

Influence of Gd on the Corrosion Behavior of AM50 and AZ91D Magnesium Alloys

The corrosion behavior of AM50 and AZ91D Mg alloys containing 0.2 wt% to 1.0 wt% Gd was evaluated in 3.5 wt% sodium chloride (NaCl) solution using electrochemical, gravimetric, and hydrogen evoluti...

Salt spray corrosion behaviour of new Mg–Al alloys containing Nd or Gd

Abstract The influence of chloride concentration on the salt spray corrosion behaviour of new AZ91D and AM50 alloys containing rare earth (RE) elements was evaluated. The corrosion rate of both materials increased with increasing chloride concentration, particularly for NaCl concentrations above 2 wt-%. The addition of Nd or Gd reduced the amount of β-Mg17Al12 phase and resulted in the formation of RE containing intermetallics that were less noble than the Al–Mn inclusions but more noble than the β-Mg17Al12 phase. The latter modifications decreased the corrosion rate of the AM50 alloy by up to 90% but did not give a clear benefit to the corrosion resistance of the AZ91D alloy.

Electrochemical corrosion behaviour of Mg-Al alloys with thermal spray Al/SiCp composite coatings

The corrosion protection of Mg–Al alloys by flame thermal spraying of Al/SiC particles (SiCp) composite coatings was evaluated by electrochemical impedance spectroscopy in 3.5 wt.% NaCl solution. The volume fraction of SiCp varied between 5 and 30%. The as-sprayed Al/SiCp composite coatings revealed a high number of microchannels, largely in the vicinity of the SiCp, that facilitated the penetration of the electrolyte and the subsequent galvanic corrosion of the magnesium substrates. The application of a cold-pressing post-treatment reduced the degree of porosity of the coatings and improved the bonding at the coating/substrate and Al/SiC interfaces. This resulted in improved corrosion resistance of the coated specimens. The effectiveness of the coatings slightly decreased with the addition of 5–30 vol.% SiCp compared with the unreinforced thermal spray aluminium coatings.