β Scribed by Dipl.-Chem. A. Thies; Prof. Dr. J. W. Schultze
No coin nor oath required. For personal study only.
Corrosion and passivity of Hastelloy C4 in Qβbrine, a magnesium chloride rich brine of pH 4.5 at room temperature, was studied by potentiodynamic (i(U) and C(U)) or potentiostatic polarisation. While the alloy rests passive at room temperature, no coherent, protecting passive layer is formed at temperatures above 60Β°C and potentials exceeding 0.2 V SHE. XPS analysis shows that at the rest potential and temperatures below 110Β°C, the oxide layer is about 1 nm thick and composed of chromium and molybdenum oxides without incorporation of Mg^2+^ or Cl^β^ from the electrolyte. At 200Β°C, its thickness increases 20 nm after 4 days and Mg^+^ inclusions are found. Across the weld, Scanning Reference Electrode measurements in dilute NaCl showed a homogeneous potential distribution indicating that bulk material, heat affected zone and weld have the same electrochemical properties.
π SIMILAR VOLUMES
The pitting corrosion of Al, and two Al-Cu alloys, namely (Al-2.5% Cu) and (Al-7.0% Cu) was investigated in gluconic acid (HG) solution through linear polarization and cyclic voltammetry techniques complemented with ex situ EDX and SEM examinations of the electrode surface. Inductively coupled plasm
Aluminium-thiourea (Al-thi) inhibitors were found to provide good inhibition of mild steel in water of a high specific salinity (1.0% Na,SO,) considered characteristic for recirculating water of zero-discharge cooling systems in steam plants. As in a real cooling system this water would contain calc