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Electrochemical Corrosion and Protection of Molybdenum and Molybdenum Disilicide in a Molten Soda‐Lime Silicate Glass Environment
Author(s) -
Sundaram S. Kamakshi,
Speyer Robert F.
Publication year - 1996
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1996.tb08005.x
Subject(s) - molybdenum , corrosion , materials science , polarization (electrochemistry) , electrochemistry , anode , soda lime , silicate , metallurgy , cathodic protection , silicon , electrode , chemical engineering , composite material , chemistry , engineering
Electrochemical corrosion of Mo and MoSi 2 in a molten soda‐lime silicate glass environment was studied using a two‐electrode cell with Pt as the counterelectrode. XRD, SEM, and EDS were used to characterize the corroded specimens. When Mo was cathodically polarized (‐1 V), no corrosion and a Mo surface were observed after 12 h of electrochemical corrosion. Under anodic polarization (+1 V), higher corrosion (0.42 mm) was observed due to formation of MoO 2 , which did not form a coherent passive layer. Cathodic protection occurred by electrostatic repulsion of oxygen ions, thus discouraging oxidation of Mo. Anodically polarized (+1 V) MoSi 2 showed a significant decrease in recession at the glass line due to formation of SiO 2 product which attenuated convective flow currents. Accelerated corrosion was observed under cathodic polarization (‐1 V), where streams of Mo particles were observed flowing downward in the melt. MoSi 2 was interpreted to decompose into neutral molybdenum and silicon anions, which were rejected into the melt.