Mineral coating: technology features, commercialization opportunities
It has been investigated the corrosion resistance, strength and plasticity of vanadium-based ternary (V-Ti-Cr) alloys in a steam–water medium. It has been found the optimum compositions with the best properties.
The report presents the results of a comparative analysis of logical and probabilistic safety threats structure modeling techniques. It is shown that general logic probabilistic method using the functional integrity of the scherme, is most preferred for use in the problems of the consolidated risk assessment.
A major concern in using vanadium alloys for first wall/blanket systems in fusion reactors is their activity with regard to nonmetallic impurities in the coolants. This paper presents the results of studying the corrosion resistance in high-purity liquid lithium (with the nitrogen and carbon content of less than 10–3 wt %) of vanadium and vanadium alloys (V–1.86Ga, V–3.4Ga–0.62Si, V–4.81Ti–4.82Cr) both in the initial state and preliminarily irradiated with Ar+ ions with energy of 20 keV to a dose of 1022 m–2 at an irradiation temperature of ~400°C. The degree of corrosion was estimated by measuring the changes in the weight and microhardness. Corrosion tests were carried out under static isothermal conditions at a temperature of 600°C for 400 h. The identity of corrosion mechanisms of materials both irradiated with Ar ions and not irradiated, which consisted in an insignificant penetration of nitrogen into the materials and a substantial escape of oxygen from the materials, causing the formation of a zone with a reduced microhardness near the surface, was established. The influence of the corrosive action of lithium on the surface morphology of the materials under study was found, resulting in the manifestation of grain boundaries and slip lines on the sample surface, the latter being most clearly observed in the case of preliminary irradiation with Ar ions.
The corrosion resistance of aluminothermic vanadium and vanadium-based binary (with 10 and 35 at. % Ti) and ternary (V–Ti–Cr) alloys in lithium is studied upon neutron irradiation. Samples of the alloys sealed in lithium-filled ampules are irradiated with fast neutrons to a fluence of 1023 cm–2 at 350–830°C in a BOR-60 reactor. It is found that the concentration of interstitial impurities (oxygen and carbon) at the surface of vanadium alloys upon irradiation is higher than that in the alloys studied under static conditions. When the vanadium alloys operate under irradiation and attack by lithium used as a heat-transfer medium, a high contamination of the surface layers in the alloys with interstitial impurities and their effect on the physical and mechanical properties of the alloys it should be taken into account.