Investigating Localized Corrosion and Sputtering Feasibility of Amorphous Chromium-Containing Alloys.
Interim technical rept. 1 May 77-30 Apr 79,
BATTELLE COLUMBUS LABS OHIO
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For the past two years research has been directed toward understanding and utilizing the corrosion resistant properties of amorphous alloys based on the composition Fe-Ni-Cr-P-B. The research had two objectives a separating initiation from propagation stages of localized corrosion phenomena and characterizing the tendency for each and b developing a sputtering technique as a means for preparing these alloys. Propagation of localized corrosion was studied in prepared crevices, which circumvented the need for initiation at structural heterogeneities at alloy surfaces. A series of amorphous alloys with chromium contents ranging from 0 to 16 atomic percent was investigated. Classical anodic polarization experiments in acidified chloride electrolytes indicated that the chromium-containing alloys were extremely passive, pitting occurring only above about 1 VSCE in 1 M NaCl at pH 1. The existence of classical active-passive polarization behavior suggested that the susceptibility of these alloys to crevice corrosion would be considerably less than that of crystalline stainless alloys, such as Type 304 and Incoloy 800 steels. Experiments in the crevice cells indicated that the amorphous alloys do crevice corrode, but only at very noble potentials comparable to those required for pitting. The sputtering research resulted in a procedure for depositing amorphous alloys with corrosion resistance almost as good as that conferred by liquid quenching.
- Properties of Metals and Alloys