Use of high-energy laser radiation for surface preparation of magnesium for adhesive applications

Norbert Schneider, Christian Wrobel
2015 Applied Adhesion Science  
Magnesium alloys are very versatile materials. Their high specific strength, combined with easy machining, suggest their application in any kind of lightweight structure [1] . For the use of magnesium in multi-material constructions, i.e. in combination with other materials, efficient joining technologies need to be developed. Adhesive bonding is a process that is perfectly suited to connect different materials. Due to its position in the electrochemical series (standard potential E 0 : −2.362
more » ... ), magnesium is a base metal [2] . This means that magnesium corrodes very easily, especially in contact with other metals. In this respect the surface pretreatment and corrosion protection are major challenges in order to ensure the durability of the adhesive bond. The functionalization of magnesium surfaces by high-energy laser radiation is a promising and cost saving alternative to mechanical (e.g. grinding) or chemical pretreatment methods like pickling or anodizing [3]. Experiments For this work the magnesium alloy MgAl3Zn (AZ31) was used. This alloy is composed of at least 3.0 % aluminum (Al), 1.0 % zinc (Zn), 0.35 % manganese (Mn) and the rest magnesium (Mg) [4]. The thickness of the metal sheets was 0.5 mm. For these experiments a Nd:YAG-Laser was used. It has a wavelength of 1064 nm, a maximum mean laser power of 100 W and the laser pulse frequency can be varied Abstract This paper is intended to demonstrate how the parameters for the surface preparation of magnesium alloys for adhesive bonding can be optimized. The effects of different laser parameters are analyzed by using a combination of advanced sample preparation and ultra-high resolution scanning electron microscopy on a nanoscale level and a specific combination of mechanical tests on the macroscopic level. These data allow a discussion of the physical principles and the key parameters influencing the interaction of laser radiation with the magnesium surface.
doi:10.1186/s40563-015-0044-2 fatcat:pf44lbzhbnce7i5lvvvashvooe