Search

Few hydride-ion conductors exhibit chemical stability and hydride-ion conductivity, which are essential properties in developing hydride-ion-driven electrochemical devices. Herein, we successfully synthesized a novel hydride-fluoride system, SrMgH4 − xFx, possessing high atmospheric stability and relatively high hydride-ion conductivity. The correlation between anion composition, structure, hydride-ion conductive properties, and atmospheric stability in the hydride-fluoride system was elucidated. The doping of fluoride ions at hydrogen sites resulted in high atmospheric stabilities while retaining hydride-ion conductivities of SrMgH2F2 and SrMgHF3 of 3.4 × 10− 4 and 1.4 × 10− 4 S cm− 1 at 400°C, respectively. For SrMgHF3, in particular, 84% ionic conductivity was retained after exposure to the atmosphere. Hydride-fluoride systems enable the balancing of the ionic conductivity and atmospheric stability by controlling the H/F ratio. Our findings provide insight for use in effective material design to expand the use of metal hydrides in practical solid electrolytes for use in hydride-ion-driven devices.

We consider the following nonlinear Schr\"{o}dinger equation with an inverse potential: \[ i\frac{\partial u}{\partial t}+\Delta u+|u|^{\frac{4}{N}}u\pm\frac{1}{|x|^{2\sigma}}u=0 \] in $\mathbb{R}^N$. From the classical argument, the solution with subcritical mass ($\|u\|_2, Comment: arXiv admin note: text overlap with arXiv:2007.15968

Leaded free-machining steel is used in production industry. However the use of the leaded free-machining steel is limited from an environmental problem. So sulfurized free-machining steel, not include lead, has been researched widely. In order to improve the machining performance of the sulfurized free-machining steel, it is necessary to find out the behavior of inclusion. The experiment was carried out to find out the mechanism of the surfurized inclusion on the machinability, using some kinds of materials which were changed the size of the inclusion. In orthogonal cutting, the deformation behaviors of the sulfurized inclusion in the work materials were observed in the vicinity of tool face. Cutting forces were also measured and finished surfaces were observed. Besides, low speed orthogonal cutting in Scanning Electron Microscope (SEM) which was mounted a small cutting device was carried out in order to observe the deformation behavior more microscopically. As a result, it is clear that some inclusions creates voids around them and some broke to several pieces depending on their conditions. Moreover, in order to investigate the formation and growth of BUE, a quick stop experiment was done during turning. As a result, it is clear that the larger inclusions can reduce the formation of BUE.

The effect of Ca addition for improving machinability in carbide tool machining operation has been widely known. It has been proposed that oxide inclusions, which would work as “belag” on the tool surface during machining operation, has been responsible for this effect. In recent years, when Ca-treated steels containing higher sulfur are machined, MnS has been observed to form on the rake face, and this “inclusion layer,” instead of the oxide belag, would serve favorably for machinability.In this paper, we have investigated the influence of several inclusions and the addition of Ca and/or Mg on rake face wear of carbide tools. The rake face wear of Ca-added steel was appreciably reduced due to the MnS inclusion layer formed on the rake face. However, the concurrent addition of Ca and Mg to the steel did not improve the rake face wear. Combined with a TEM observation in a cross section of MnS layer formed on the rake face, these results are understood by the different nature of oxide inclusions in terms of abrasive wear.

2022