Effect of Al content on the corrosion behavior of Mg–Al alloys in aqueous solutions of different pH

A Comparative Study on the Corrosion Resistance of Cerium-Based Conversion Coatings on AZ91D and AZ31B Magnesium Alloys

“…The cerium conversion coated AZ31B Mg alloy had numerous pits and significant salting after 216 hours salt spray testing compared with minor salt tailing for the coated AZ91D alloy. Nevertheless, the good salt spray performance of AZ91B alloy compared to AZ31B alloy with and without coating is not surprising because it has been reported that the increasing of Al content in Mg alloys generally leads to a better corrosion resistance, especially for greater than 5 wt% Al in the Mg matrix (14). A comparison of the surface morphologies of AZ31B and AZ91D Mg alloys after CeCC is presented in Figure 3.…”

“…Several reviews have summarized the state of the art of the corrosion mechanisms of magnesium and magnesium alloys, including a large number of protective surface modification technologies (3,(5)(6)(7)(8)(9). For the AZ series of Mg alloys it is widely recognized that increasing Al content into the alloy generally leads to better corrosion resistance [8,[10][11][12][13][14]. It has been also demonstrated that corrosion of Mg alloys can be minimized by reducing surface contaminations and applying protective coatings (5,6,9).…”

The influence of manufacturing processes on the microstructure and corrosion of the AZ91D magnesium alloy evaluated using a computational image analysis

“…A high volume fraction of ␤-phase, in particular when forming a continuous network, can act as a barrier for further corrosion attack. A high Al content in the Mg-grain leads to a more noble potential as well as to the formation of a more protective oxide, depending on the electrolyte [16,[19][20][21][22]. Since the casting technique strongly affects these microstructural aspects, processing is likely to be an effective tool to improve the corrosion resistance of magnesium alloys.…”

Prediction of corrosion rate of AZ31B magnesium alloy under salt fog environment in NaCl solution

“…Mg17Al2 has a higher standard potential and exhibits a more passive behavior over a wide pH range in chloride solutions than either Al or Mg. Due to selective attack along the β phase networks, they were gradually attacked and peel from the surface forming the pits was expected to take place at these sites. It meant that the pH value was one of the major factors of corrosion rate [29]. Fig.…”