Ilona Felhősi

Innovative heat- and corrosion-resistant coating approaches, applicable in indirect-food-contact outdoor environments, have been developed. Two systems, a direct-to-metal single-layer, polysiloxane-based, oven-dried system and a bilayer, zinc phosphate active pigment-containing, ambient-cured system were developed to overcome the shortcomings of the traditional bilayer, zinc-rich primer-based heat-resistant surface-protective solutions for outdoor cooking equipment, such as barbecue grills. This case study aims to optimize the application conditions, measure and evaluate the impact of surface preparation and compare thermo-resistant and anticorrosive properties of different coating systems focusing on eco-efficiency. The anticorrosion efficiency of the coatings was characterized using salt-spray chamber corrosion tests and electrochemical impedance spectroscopy. The thermo-resistant character of the coatings was tested by cyclic and constant heat treatment, after which the physical integrity of the coatings was evaluated by optical microscopy. In the overall performance of the coatings, the roughening of the steel substrate surface and the thickness of the coatings were also considered as influential parameters. The study revealed that the newly developed coatings have superior anticorrosion performance to the usually applied Zn-rich coating. The Single-layered Coating has excellent corrosion resistance under certain conditions and has the advantage of fast layer application. The Bilayered Coating showed excellent heat- and corrosion-resistance properties even on a surface without sand-blasting.

Tin–silver–copper (SAC) solder alloys are the most promising candidates to replace Sn–Pb solder alloys. However, their application is still facing several challenges; one example is the electrochemical corrosion behaviour, which imposes a risk to electronics reliability. Numerous investigations have been carried out to evaluate the corrosion performance of SAC lead-free alloys, regarding the effect of the corrosive environment, the different manufacturing technologies, the effect of fluxes, the metallic contents within the SAC alloys themselves, and the different alloying elements. In these studies, widely used electrochemical techniques are applied as accelerated corrosion tests, such as linear sweep voltammetry and electrochemical impedance spectroscopy. However, there is lack of studies that try to summarise the various corrosion results in terms of lead-free solder alloys including low-Ag and composite solders. This study aims to review these studies by showing the most important highlights regarding the corrosion processes and the possible future developments.