List of top Engineering Materials Science Questions on Corrosion asked in GATE XE

Corrosion of pure iron takes place in an acidic electrolyte by forming \(Fe^{2+}\) ions at ambient condition. The corrosion current density is measured to be \(2 \times 10^{-4} \, A \, cm^{-2}\). The corrosion rate (in mm per year) of iron is (rounded off to one decimal place). Given: \[ \text{Atomic weight of iron} = 55.85, \rho = 7.86 \, g/cm^3 \] \[ \text{1 year} = 365 \times 24 \times 3600 \, s, 1F = 96500 \, C/mol \]

The slopes of reduction potential vs. pH plots for the reactions: 1. \(NiO + 2H^+ + 2e^- \rightleftharpoons Ni + H_2O\) 2. \(2H^+ + 2e^- \rightleftharpoons H_2\) at 298 K are \(S_1\) and \(S_2\). The ratio \(\dfrac{S_1}{S_2}\) is (rounded off to one decimal place).

Two moles of a monoatomic ideal gas at 10 atm and 300 K is expanded isothermally and reversibly to a pressure of 2 atm. The absolute value of work done by the system is (in kJ) .......... (rounded off to two decimal places).

In a Raman spectroscopy experiment done at 300 K, a Raman line is observed at $200 \, cm^{-1} \, (\sim 25 \, meV)$. The ratio of the intensity of the Stokes line to that of the Anti-Stokes line is ............ (rounded off to two decimal places). Given: Boltzmann constant, $k = 8.62 \times 10^{-5} \, eV K^{-1}$

When a metal (M) is immersed in de-aerated acid electrolyte, it polarizes anodically by 0.4 V. The M/M\(^{n+}\) exchange current density is \( 10^{-5} \, \text{A m}^{-2} \) and Tafel slope is 0.1 V/decade for the anodic reaction. Assume that corrosion is uniform and anodic and cathodic reactions are under activation control. The rate of metal dissolution in A m\textsuperscript{-2 is \(\underline{\hspace{2cm}}\) (round off to 1 decimal place).}