The magnetic and corrosion properties of iron cobalt chromium films

The influence of alloy composition on the magnetization and atmospheric corrosion of thin films has been measured. Films were prepared by sputtering from a target composed of separate segments of Fe, Co, and Cr. Film composition at different locations varied according to the different distances from the three segments in the source. Microprobe analysis was used to measure the compositions as a function of location. Compositions ranged from 75% to 10% Fe, from 75% to 10% Co, and from 45% to 5% Cr. From the relationship between composition and location in the film, properties measured at various locations could be interpreted as measurement on various compositions. A smooth surface was fitted to the measurements in the composition graphs to provide the benefits of averaging and interpolation. X-ray diffraction showed the compositional dependence of the phase boundaries in these films and provided lattice constants. Magnetic measurements were made by cutting the film into small enough pieces to have only minor composition ranges and by a magneto-optic method which sampled very small areas. Atmospheric corrosion was assessed by measuring the roughness induced by exposure to a corrosive gas test designed to simulate indoor atmospheres. These data are presented as contoured surfaces on composition maps.