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The effect of temperature on the corrosion behaviour of Inconel alloys employed for the electroreduction of metal oxides to metals in a lithium molten salt was investigated. The ratio of the weight loss of Inconel 601 and 690 to that of Inconel 600, Inconel 601 and 690 was approximately four and six at 650 °C, and five and eight times higher than that of Inconel 600 above 750 °C for 72 h, respectively. The corrosion products of all the alloys tested at 650 °C and 750 °C for 72 h were mainly Cr2O3and FeCr2O4; however, only Cr2O3was obtained when Inconel 690 was corroded at 750 °C or higher. Additionally, an alloy with a composition of max. 16.3 wt.% Cr, min. 73.66 wt.% Ni and well below 8.15 wt.% Fe was expected to exhibit excellent corrosion resistance in a lithium molten salt system at 650–850 °C.

As a result of rapid advancements in urban infrastructure and technology, transportation is transforming a variety of innovative and emerging services. This paper introduces the concept of transportation-enabled services (TRENS), which is a service model that uses transportation systems to enable and enhance the delivery, accessibility, and effectiveness of nontransportation services. We establish a general framework in which the transportation-enabled services involve four key stakeholders: customers, suppliers, TRENS providers, and transportation carriers. Within this general framework, we present five specific service models: a one-sided market, three variants of two-sided markets, and a three-sided market, each characterized by the interactions among suppliers, TRENS providers, and transportation carriers. Taking different models of transportation-enabled services into consideration, we highlight crucial research opportunities to enhance understanding of the planning, operations, evaluation, and regulation of transportation-enabled services. These research opportunities include demand and supply management, transportation system management and operations, coordination among stakeholders, and the evaluation and regulation of transportation-enabled services. We believe that the emergence, widespread adoption, and popularity of transportation-enabled services will significantly enhance and reshape many services and thus contribute to the overall improvement of future mobility in the broader context of smart cities.History:This paper has been accepted for the Service ScienceSpecial Issue on Innovation in Transportation-Enabled Urban Services.Funding:The work of Hai Wang was supported by the Lee Kong Chian Fellowship awarded by Singapore Management University. The work of Hao Sun was supported by the National Natural Science Foundation of China [Grants 72301179].

ABSTRACTThe isothermal and cyclic corrosion behavior of yttria (Y2O3)-stabilized zirconia (ZrO2) in a LiCl-Li2O molten salt were investigated at 650 °C in an argon atmosphere. During isothermal and cyclic corrosion tests in the molten salt of LiCl-Li2O for 168 h and 7 thermal cycles, the corrosion rate was very low, whereas under the molten salt of LiCl-Li2O-Li for 168 h, the corrosion rate was almost 10 times higher than that in the molten salt of LiCl-Li2O. No corrosion product was detected until 168 h for the isothermal corrosion test, however, after 7 thermal cycles, a very-low-intensity Li2ZrO3peak was detected at the beginning stage of the chemical reaction between ZrO2and Li2O. Additionally, in the molten salt of LiCl-Li2O-Li for 168 h, a large amount of Li2ZrO3was formed, with evidence of marked cracks, pores, and spallations on the corroded surface. The introduction of Y2O3-stabilized ZrO2was beneficial in increasing the hot corrosion resistance of the structural materials used to handle molten salts containing Li2O at elevated temperature without forming a lithium at the cathode during the electrolytic reduction process.

In this study, the corrosion behavior of new Ni-based structural materials was studied for electrolytic reduction after exposure to LiCl-Li2O molten salt at 650 oC for 24-216h under an oxidizing atmosphere. The new alloys with Ni, Cr, Al, Si, and Nb as the major components were melted at 1700 oC under inert atmosphere. The corrosion products and fine structures of the corroded specimens were characterized by SEM, EDS, and XRD. The corrosion rate of 12wt% Cr-2wt% Si alloys and 12wt% Cr-5wt% Si alloys are below 0.3mm/year. However, the corrosion rate of 20wt% Cr-5wt% Si is 0.6mm/year. Also, the corrosion products of 12wt% Cr alloys were Cr2O3, NiCr2O4, Ni, and NiO; those of 20wt% Cr alloys were Cr2O3, LiAl2Cr3O8, and NiO. The higher corrosion rate of 20wt% Cr-5wt% Si could be the higher solute concentration which leads to an unstable alloy formation. As confirmed by the pseudo binary phase diagram of (Ni-Cr-Al-Nb)-Si, the solubility of the silicon with 20 wt% of Cr decreased to 4 wt% from 5 wt% with 12 wt% of Cr.

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is too corrosive for typical alloying structural materials. Therefore, the choice of the optimum material for the processing equipment that handles molten salt is critical. We investigated the corrosion behaviors of CaO-stabilized ZrO2(CSZ) and mullite (Al6Si2O13) at 650°C for 168 h in molten (1, 3) wt% Li2O–LiCl. The as-received and tested specimens were examined by scanning electron microscopy/X-ray energy dispersive spectrometry and X-ray diffraction. CSZ showed a much better hot-corrosion resistance in the presence of Li2O–LiCl molten salt than mullite. The surface corrosion layers of mullite consisted of LiAlSiO4in 1 wt% Li2O–LiCl, and a LiAlO2phase appeared as the Li2O concentration increased to 3 wt%. Furthermore, Li2SiO3was the only corrosion product observed at 3 wt% Li2O–LiCl. The surface corrosion layers of CSZ were composed mainly of tetragonal-ZrO2with partial monoclinic-ZrO2in 1 wt% Li2O–LiCl, and a Li2ZrO3phase appeared at 3 wt% Li2O–LiCl. There was no corrosion product detached from the surface for those specimens. CSZ was beneficial for increasing the hot-corrosion resistance of the structural materials that handle high-temperature molten salts containing Li2O.

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