Oxide growth and conversion on carbon steel as a function of temperature over 25 and 80°C under ambient pressure

Inverse Crevice Corrosion of Carbon Steel: Effect of Solution Volume to Surface Area

“…Maghemite has a major, broad peak over the range of 670 to 718 cm -1 , has the same oxide structure as magnetite, and also has a low Raman scattering probability. 38,39 The bold-surface spectrum is very similar to that of iron-oxide nanoparticles formed by γ-irradiation of a solution initially containing ferrous ions. 17 Those iron-oxide nanoparticles were identified as magnetite with a hydrated and hydrolyzed surface (i.e.…”

Mass and Charge Balance (MCB) Model Simulations of Current, Oxide Growth and Dissolution during Corrosion of Co-Cr Alloy Stellite-6

“…The potential drop across the entire oxide layer on Stellite-6 at a given time can be expressed as: [10] where and ε Formulation of oxide growth and dissolution fluxes.-Oxide formation will compete with dissolution for the metal cations produced by the electrochemical oxidation reactions. Due to mass balance the oxide growth flux (J M O# (t)| oxide ) and the dissolution flux (J diss# (t)| sol ) are not independent and are related to the oxidation flux as: [13] where k M O# (t) is the first-order rate constant for the formation of oxide, MO# at time t and k diss# is the first-order rate constant for the dissolution of M# n+ from the oxide into solution. The dissolution of the metal cations formed during corrosion occurs via surface hydration of the metal cation and the rate constant for this process will depend only on the surface hydration energy of the oxide.…”

“…The result can be a complex and shifting set of oxides that form and grow as a function of time. 10,[13][14][15][16][17] The MCB model applies the three flux equations to each metal oxidation reaction leading to the formation of a specific oxide and the dissolution of the different metal ions. For each oxidation reaction, the MCB model imposes the mass and charge balance requirements and the reaction thermodynamic and kinetic constraints on each metal oxidation process.…”

“…The nature of oxide and the oxide layer structure can also change with time as corrosion progresses even under potentiostatic polarization or constant solution conditions. [8][9][10][12][13][14][15][16][17] The type of oxide that can form and its rate of formation depend on solution environmental parameters such as pH, temperature and the concentrations of redox active species. Few existing models specifically incorporate the solution environment in their model parameters and, even in those models that do so, the effects are formulated primarily based on empirical relationships.…”

“…Alloys owe their corrosion resistance to protective oxide films formed on their surfaces. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Corrosion involves surface redox reactions (metal oxidation coupled with solution reduction) and interfacial transfer of the charged species involved in the redox reactions. The presence of an oxide film hinders the interfacial charge transfer, slowing the rate of corrosion.…”