Magnesium and magnesium alloys are the lightest structural materials with an approximate density of 1.7 g/cm³ (density of aluminium ~2.7 g/cm³). Due to the poor corrosion and wear resistance properties, they need to be coated for usage in lightweight constructions. AlSi20 was found to be a suitable coating material to improve the properties of parts made of the magnesium alloy AZ31B. Within this work, coatings are applied by thermal spraying, laser cladding and the combination of both processes. These coatings were investigated regarding corrosion protection in 3.5 % chlorine solution in a three electrode setup to obtain electrochemical corrosion characteristics. Abrasive wear was investigated using a pin-on-disc tribometer and abrasion rate was calculated. Resistance against shock loads was tested by applying a cyclic load at 50 Hz in order to investigate the resistance against impact stresses.

Saving energy is a major concern in every aspect of the economy, especially in the automotive and aerospace industry. The use of lightweight materials is one way to reduce weight of moving parts and thus energy consumption. Research activities to improve the porosity on the one hand, and the coating properties like wear and corrosion resistance on the other hand, show the potential of a hybrid coating process. The creation of thermal-sprayed coatings and a laser post-treatment enable a minimization of porosity and an improvement of wear properties. Different coating materials (e.g. Al-Si alloy) have been investigated regarding microstructure, hardness, wear- and corrosion protection.

This paper reviews the results of thermal spraying on the magnesium alloy AZ 91. By plasma, arc and HVOF spraying various metal based alloys were used as coating materials. The layers were investigated with regard to microstructure, bonding and corrosion resistance. Paper text in German.