Evaluation of anti-adhesive and corrosion protection properties of TiAlSiN-magnetron-sputtered films for applications in polymer processing

• Screening corrosion properties as function of Si content in ternary TiAlSi nitrides. • (Ti+Al)/Si ratios varied from 0.7 to 4.2 in a combinatorial sputtering deposition. • Films with higher Si content showed improved corrosion resistance. • Anti-adhesive properties between coating and PC melt are not affected by Si content. Steel substrates were coated with TiAlSiN thin films with varying Si content using a combinatorial approach based in magnetron co-sputtering of TiAl and Si targets. The coatings were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction, and Raman spectroscopy. The films were amorphous and showed (Ti+Al)/Si ratios ranging from 0.7 (TiAl 3.0 Si 5.6 O 5.8 N 5.1 ) to 4.2 (TiAl 3.6 Si 1.1 O 4.4 N 2.6 ). The influence of the film composition on the surface oxidation and the corrosion resistance was investigated by near ambient pressure XPS and electrochemical methods. The films exhibited improved corrosion resistance with increasing Si-content. The adhesion properties were explored by investigating the interaction of the coatings with polycarbonate (PC). PC was melted onto the samples and the thickness of insoluble PC residue was investigated by ellipsometry, atomic force microscopy and nanoscale infrared spectroscopy. The results indicate that the incorporation of Si mainly promotes corrosion resistance, without altering the good anti-adhesive properties of TiAlN films.