Investigating the Effects of Low Temperature Annealing of Amorphous Corrosion Resistant Alloys.
Rept. no. 3 (Final) 1 May 77-31 Oct 80,
BATTELLE COLUMBUS LABS OH
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This research program was conducted in two phases. Annealing-induced changes in corrosion and mechanical properties of amorphous alloys were investigated during 1979-80, whereas earlier studies during 1977-1979 involved characterizing the localized corrosion resistance and feasibility of sputtering such alloys. Annealing, performed at temperatures up to that causing crystallization, produced embrittlement of Fe32Ni36Cr14P12B6 at 100-200 C, as measured by bending. Embittlement preceded crystallization, which initiated during a substantially higher temperature of 400 C. Annealing of Fe32Ni36Cr14Si6B12 resulted in embrittlement at 300-400 C, which coincided with crystallization in this alloy. Segregation of phosphorus is believed to have caused embrittlement of the former alloy, whereas embrittlement of the latter was probably induced by crystallization. Susceptibility of both alloys to corrosion in chloride solutions increased dramatically with the occurrence of crystallization. This increase appeared as a reduction in the critical pitting potential with increasing degree of crystallization. Research performed during 1977-1979 showed that Fe-Ni-Cr-P-B alloys resist crevice corrosion as well as pitting. This observation was interpreted as indicating that even if initiation of localized corrosion is facilitated by introducing a crevice geometry, corrosion cannot proceed because of the considerable resistance of these alloys to propagation of attack. It was also demonstrated that these alloys can be sputtered as amorphous layers that exhibit essentially the same resistance to pitting corrosion as alloys of similar composition, but prepared by liquid quenching. Author
- Properties of Metals and Alloys
- Fabrication Metallurgy