Corrosion-electrochemical behavior of nickel in the LiCl–KCl melt, containing lantan trichloride

E. A. Karfidov, E. V. Nikitina

ABSTRACT

The effect of temperature in the range from 500 to 800°C on nickel (N1) corrosion was studied during testing in a salt melt of a eutectic mixture of lithium and potassium chlorides, with the addition of lanthanum trichloride from 0.5 to 2 mol. %. The corrosion rate of nickel increases with increasing temperature, the addition of lanthanum chloride reduces the corrosion rate at 500–650°C (inhibition of the shielding type due to the subsequent chemical reaction). The corrosion potential of nickel is approximately –0.5 V relative to the silver chloride electrode at a temperature of 500°C and decreases slightly with increasing temperature, and does not depend on the concentration of lanthanum chloride. To concretize the mechanism of corrosion damage, the current-voltage curves were taken with the content of lanthanum chloride 0.5 and 2 mol. % at sweep speeds of 10 and 20 mV/s. X-ray phase and micro X-ray spectral analysis methods were used. The sweep speed does not affect the course of the irreversible electrochemical oxidation process, and the addition of lanthanum chloride increases the current density in the anode region tenfold. Comparison of corrosion rates obtained by gravimetric and chemical-analytical methods, allows us to speak about the electrochemical mechanism of corrosion.

KEYWORDS nickel, chloride melt, corrosion, lanthanum trichloride, temperature, surface morphology

DOI: 10.1134/S0235010619040078

Corrosion of various types of stainless steels in chloraluminate melts

V. V. Karpov, A. V. Abramov, K. V. Dedov, A. V. Shak, A. Yu. Zhlyakov,

I. B. Polovov, S. V. Belikov, O. I. Rebrin

ABSTRACT

In the present work the corrosion behavior of 08Kh17T (analogue of AISI 439) ferritic steel, 12Kh13 (analogue of AISI 410) and 16Kh12MVSFBR ferritic-martensitic steels, and AISI 316L (analogue of 03Kh16N15M3), 12Kh18N10T (analogue of AISI 321) and 06KhN28MDT austenitic alloys was studied at 550°C in fused KCl–AlCl3 mixture with the initial AlCl3EtoEKCl ratio of 1.1. The corrosion rates of the studied materials in the KCl–AlCl3 were determined. The corrosion processes in all the studied iron-based steels were caused by the red-ox reactions resulting in dissolution of the most electronegative alloy components (Cr, Fe and Mn), that indicate the electrochemical nature of corrosion phenomena.

KEYWORDS

corrosion, stainless steel, chloraluminate melts, intergranular corrosion, molten salt reactor

DOI: 10.7868/S0235010619010067

Corrosion investigation of steel 12Cr18Ni10Ti in the melt LiCl–KCl–nNdCl3

N. A. Kazakovtseva, M. A. Maikov, E. V. Nikitina

ABSTRACT

The high-temperature corrosion of 12Cr18Ni10Тi steel in the melt of lithium and potassium chlorides was investigated, with addition of neodymium trichlorides at an operating temperature of 773 K. The NdCl3 concentration varied from 0.2 to 5 mol %. In this study, neodymium is an analog of plutonium. The composition of the electrolyte was close to the composition of real electrolytes used for processing nitride spent nuclear fuel (SNF). The main method of investigation is gravimetric, with aging of the steel sample in the melt for 1–24 hours. The atomic-adjective and micro-XFray spectral analysis methods were also used.

KEYWORDS:

corrosion, neodymium, gravimetry, melts

High-temperature corrosion of steel 12Cr18Ni10Ti in the melt of lithium and potassium chlorides, with additions of trichlorides of cerium

E. V. Nikitina, N. A. Kazakovtseva

ABSTRACT

The high-temperature corrosion of 12Cr18Ni10Ti steel in the melt of lithium and potassium chlorides was investigated, with addition of cerium trichlorides at an operating temperature of 773 K. The CeCl3 concentration varied from 0.2 to 5 mol%. In this study, cerium is an analog of plutonium. The composition of the electrolyte was close to the composition of real electrolytes used for processing nitride spent nuclear fuel (SNF). The main method of investigation is gravimetric, with aging of the steel sample in the melt for 1–24 hours. The atomic-adjective and micro-X-ray spectral analysis methods were also used.

KEYWORDS:

corrosion, neodymium, cerium, gravimetry.