Kinetics of the Chloride-Induced Oxidation of Iron at 300 C.
NAVAL RESEARCH LAB WASHINGTON D C
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Iron was oxidized in the absence of oxygen at 300C in solutions containing chloride andor ironII ions. The oxidation reaction was conveniently studied by the hydrogen-effusion method, which determines the rate at which hydrogen is evolved. The generally accepted concept that chloride ions accelerate the oxidation of iron has not received experimental verification, because, in addition to chloride ions, the system must contain ironII ions. An empirical equation has been derived that describes the extent of iron oxidation W with time t as a function of the ironII chloride molar concentrations. Magnetite, or Fe3O4, is deposited as a tightly adhered crystalline film at the metalsolution interface and apparently also quenches the reaction rate by serving as a physical barrier. The differential with respect to time of a term of the equation describes a rate mechanism that is proceeding under the diffusive control of ions migrating across the Nernst boundary layers of anodic and cathodic regions of an oxide-free metalsolution interface. Author
- Inorganic Chemistry
- Metallurgy and Metallography