Influence of Conversion Coating on Magnesium and Aluminum Alloys by Adhesion Method

Abstract

Magnesium alloys are lightweight materials with high specific strength and have electromagnetic shielding characteristics. On the other hand, chromate is known as carcinogen and it leads a limited use of the conversion coating on magnesium. In recent years, adhesion technology is essential and widely used in producing electronic equipment and sporting goods from magnesium alloys. Adhesives can easily bind different materials. Adhesives may even inhibit the contact corrosion of magnesium, and we may expect adhesion to be used to effectively join different metals.This paper describes and compared with the influence of various non-chromate conversion coatings on the bonding strength of magnesium and aluminum alloys.In this study, specimens of AZ31B and A2017, A6022 were used. The adhesive cements used were epoxy and acrylic resin. The results of a pull-off test and tensile lap-shear strength test ware evaluated.The Mg(OH)2 coating on AZ31B and Boehmite on A6022 exhibited a higher tensile shear strength (16 MPa) with epoxy resin. In the acrylic resin, Mg(OH)2 coating on AZ31B and Boehmite on A6022 had a tensile shear strength of 14 MPa.It is obvious that these conversion coatings can be alternatives to chromate conversion coatings as surface treatment for adhesion of magnesium alloys and aluminum alloys.