Corrosion properties of sputter-deposited steel thin film for electrical resistance sensor material

Steel thin films for an electrical resistance sensor were prepared by sputter deposition. It was revealed that the electrochemical properties of the thin films were influenced by the surface roughness. Using an Al2O3 substrate with high surface roughness, it was possible to obtain a steel thin film with corrosion characteristics similar to bulk steel. The corrosion rate of the thin film was fairly well matched with bulk steel, enough to use as a sensor material. The fabricated thin film electrical resistance sensor had a high enough sensitivity to detect a corrosion rate of 0.01 mm/y or less. Moreover, a specially designed multiple-line electrical resistance sensor could successfully discriminate the localized pitting-type corrosion.