Zn-Mg and Zn-Mg-Al alloys for improved corrosion protection of steel: Some new aspects

The performance of ZnMg and ZnMgAl coatings for corrosion protection of steel crucially depends on a number of factors. One is the degree of alloying. For instance, under standard testing conditions very promising inherent resistance against paint delamination even without conversion treatment was reported for highly Mg-alloyed zinc coatings. However, it will be shown in this work that under certain conditions very fast delamination may occur. For the much lower alloyed ZnMgAl coatings that are at the main focus of current research, as well as for lower alloyed ZnMg microstructural aspects of their corrosion performance will be discussed in more detail.