Optical,mechanical and corrosion properties of metal-metal and metal-dielectric thin layered films

Optical, mechanical and corrosion properties have been studied on the following bilayer coatings: Cr-(67% Cu + 33% Zn), Ti-(67% Cu + 33% Zn), CuZn, AuCr, CrCu and CuNi. Both Crbrass and CrCu were studied with overlayers of SiO₂, with and without thin underlayers of Cr next to the SiO₂. Thus the systems CrCuCr, CrbrassSiO₂, brassCrSiO₂ and CrCuSiO₂ were also studied. These were compared with single layers of brass, Cr and Cu. Layered structures were deposited in both MRC diode and NRC triode sputtering systems. The triple-target r.f. diode system was used to sputter sequentially three different layer thicknesses. The thickness of the metallic layers was varied between 5 and 200 Å, while the SiO₂ thickness was kept constant at 670 Å. Results are presented for the optical reflectance and transmittance in the region 0.6–4.0 eV, the solar transmittance factors, DW (nm) and saturation index P. Hardness, scratch resistance and corrosion resistance tests under cyclic conditions were also made. It is shown that layering is a powerful technique for control of the optical, mechanical and corrosion resistance properties of the films.