On the electrodeposition and characterization of niobium from fused fluoride electrolytes
The electrodeposition of niobium from a binary electrolyte consisting of KF and NaF was characterized and compared with that from the ternary electrolyte of LiF, NaF and KF. The deposition experiments were conducted at current densities between 5 and 35 mA cm−2 and electrolyte temperatures between 725 and 800°C. DTA measurements indicated the melting points to be 450 and 710°C for the ternary and binary electrolytes with added K2NbF7; however, it was necessary to operate both electrolytes above 725°C to obtain dense coherent deposits. Coating morphology was described by optical and scanning electron microscopy studies, while coating structure and properties were characterized by X-ray diffraction analysis. In particular, a series of diffraction measurements were reported to describe the changes in the microstructure of the deposited material as a function of the preparation conditions.
Coherent Coatings of Refractory Metal
A general process has been developed for the electrodeposition of eight of the nine refractory metals of groups IVB, VB, and VIB as dense coherent deposits. It consists essentially of the electrolysis of a solution of the refractory metal fluoride in a molten alkali-fluoride euteotic mixture, and has been shown to deposit a coating, unalloyed with the substrate, by a pro- cess that obeys Faraday's law. Some evidence exists that the electrode-reaction mechanism by which coherent coatings are deposited from molten salts incorporates an irreversible metalproducing step.
Physical Ageing of the Research Reactor Core Structural Materials Due to Neutron Irradiation Exposure: a Review
A research reactor (RR) is a  nuclear reactor that has function to generate and utilize neutron flux and radiation ionization for  research purposes and industrial applications. More than 60% of current operating RRs have  been operated for 30 years or more. As the time passes, the functional capabilities of structures,  systems and components (SSCs) of those RRs deteriorate by physical ageing, which can be  caused by neutron irradiation exposure such as irradiation induced dislocation and  microstructural changes. To extend the lifetime and/or to avoid unplanned outages, ageing on  the safety related SSCs of RRs need to be properly managed. An ageing management is a  strategy to engineer, operate, maintenance, and control SSC degradation within acceptable limits. The purpose of this study is to review physical ageing of the core structural materials of  the RRs caused by neutron irradiation exposure. In order to achieve this objective, a wide range  of literatures are reviewed. Comprehensive discussions on irradiation behaviors are limited only  on reactor vessel and core support structure materials made from zirconium and beryllium as  well as their alloys, which are widely used in RRs. It is found that the stability of the mechanical  properties of zirconium and beryllium as well as their alloys was mostly affected by the neutron  fluences and temperatures.