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The hot corrosion behaviors of Inconel alloys with different Cr contents (Inconel 600, 601, and 690), which are used widely in nuclear plants, were investigated in molten LiCl–Li2O salts. The hot corrosion behaviors were studied by measuring the mass and attack depth changes, surface and cross-sectional morphologies and elemental distributions, and compositional changes at the subscale and substrate scale as well as the spalled oxide scale. At 288 h, the weight losses of Inconel 601 and Inconel 690 were approximately four and twelve times higher, respectively, than that of Inconel 600. The corrosion products of all tested alloys were Cr2O3, NiO, and FeCr2O4. Inconel 600, which exhibited a dense and continuous external corrosion layer and an internal corrosion layer with localized corrosion behavior, exhibited superior corrosion resistance compared with those of Inconel 601 and 690, which showed a spalled external corrosion layer and an internal corrosion layer with uniform corrosion behavior. Thus, the corrosion resistance of the Inconel alloys tested in the hot lithium molten salts in an oxidizing atmosphere is closely related to the contents of the primary alloying elements in the alloys. Of the various alloys analyzed in this study, Inconel 600 exhibited the highest corrosion resistance. Thus, a Cr content of 16.30 wt% or less, Ni content of at least 73.66 wt%, and Fe content considerably lower than 8.15 wt% can result in excellent corrosion resistance. [ABSTRACT FROM AUTHOR]

Titanium metal preparation from titanium dioxide (TiO2) has been the subject of numerous studies to overcome the chlorination processes at the heart of the Kroll process. In this study, an alumino-magnesiothermic reduction approach is employed to obtain a Ti-rich ingot via the combustion of an exothermic mixture of TiO2–KClO4–Al(Mg)-KClO4–CaF2 composition in argon. The combustion temperatures are measured, and the reaction patches are highlighted. The synthesis conditions of the Ti-rich ingot were carefully examined depending on the Al particle size, Al/Mg ratio, TiO2 precursor type, and CaF2 concentration. XRD analysis states that the ingot obtained under optimized experimental conditions is single-phase Ti metal. ICP-MS analysis revealed residual Al and O in the Ti ingot with 3.5 and 4.0 wt pct content, respectively. [ABSTRACT FROM AUTHOR]

Titanium suboxides with the general formula TinO2n−1 (n > 1.0), also referred to as Magnéli phases, have been the subject of numerous studies due to their unique properties. Titanium low oxygen suboxides located at n = 1 (TiO) or below (Ti6O, Ti3O and Ti2O) are no less important; however, there is a lack of research on the synthesis of such materials. Therefore, in this article, the combustion process in a TiO2-KClO4-kAl-Flux exothermic system for 0.5 ≤ k ≤ 4.0 (k is moles of Al) is investigated experimentally and thermodynamically to synthesize TinO2n−1 ingots in the 0.5 to 1.0 range of n. The synthesis temperatures and equilibrium reaction phases are calculated with and without a KClO4 booster and several fluxes (CaF2, NaF, CaO and Na3AlF6), which are used to melt the reaction product and achieve the self-separation of the TinO2n−1 ingot from the Al2O3-containing slag. The formation TiO, Ti2O, Ti3O and Ti6O phases is confirmed via XRD analysis and the effectiveness of fluxes is highlighted. [ABSTRACT FROM AUTHOR]