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Growth of Fe 3 Si layer deposited from the molten salt
Author(s) -
Suzuki Ryosuke O.,
Nagaso Youichi,
Nakanishi Kohichi,
Ono Katsutoshi
Publication year - 2000
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.200005703
Subject(s) - chemistry , intermetallic , kirkendall effect , layer (electronics) , substrate (aquarium) , diffusion , metallurgy , materials science , thermodynamics , oceanography , physics , organic chemistry , alloy , geology
The corrosion‐resistive intermetallic compound Fe 3 Si can non‐electrolytically coat the iron substrate at 973‐1173K in the molten salt composed of NaCl‐KCl‐NaF‐Na 2 SiF 6 ‐SiO 2 . However, the adhesion of Fe 3 Si layer was weak because of the crack formation in the Fe 3 Si layer. The mechanism of the layer growth and defect formation was studied experimentally. The marker experiments showed that the salt was caught up on the initial surface and left large voids in the layer. The fast deposition of silicon on pure iron surface and the quick growth of Fe 3 Si wrapped the salt in the layer at the first stage of deposition. The Si penetration from the Fe 3 Si layer into the α‐Fe substrate was small due to the slow diffusion of Si in α‐Fe. The fast Fe diffusion in the Fe 3 Si layer left the Kirkendall holes. The formation of these defects could be suppressed in the high Si concentration‐iron alloys.