In a separate report, the pitting characteristics of sputtered thin films of aluminum and aluminum binary alloys are presented.1 These alloys have up to 40% solute in solid solution and are extraordinary resistant to pitting, exhibiting pitting potentials in chloride solutions in certain cases above +1000 mVSCE. These alloys are also very susceptible to crevice attack, especially when polarized above about 200 mVSCE. A simple method of masking samples was developed that virtually eliminates the occurrence of crevice corrosion.
Aluminum and aluminum alloy films about 1000 Å thick were sputter-deposited onto 2.54-cm diameter quartz substrates. After deposition of the alloy films, three 0.79-cm diameter copper disks were placed on top of the metal films, thereby forming physical masks for subsequent deposition. A layer of a binary oxide glass, such as ZrO2—SiO2 or TiO2—SiO2, approximately 5000Å was then deposited...
