Influence of pulsing on PVD TiAlN coating microstructure and mechanical properties : Master thesis project on the impact of deposition parameters on performance and properties of PVD titanium aluminum nitride.

Sammanfattning: This thesis investigates the influence of pulsing on the mechanical properties of PVD TiAlN coatings. The thesis focuses on defects caused by droplets during the arc-evaporation technique by altering the duty time, which affects mechanical properties. The coatings' properties and performance depend on the microstructure and morphology, which, in turn, depend on the process parameters of the PVD process. The methodology used to analyze the coatings included microscopy techniques such as SEM and EDS. The study found that coatings produced using pulsed bias exhibited a considerably higher number of droplets, i.e. the rounded topography, than those produced using DC bias. The duty cycle of the pulsed bias may play a significant role in determining the surface characteristics of the coatings, where pulsed bias coatings with a 10% duty cycle resulted in rougher surfaces, while a 20% duty cycle resulted in smoother surfaces. The surface composition of the coatings exhibits high consistency, characterized by an even distribution of titanium and elevated concentrations of aluminum and nitrogen on droplets from both methods. A higher duty cycle also led to more cracks in the coating.