1Cr18Ni9Ti激光选区熔化成形工艺参数对致密度的影响

采用正交试验,结合典型缺陷形成原因和微观组织,研究了激光选区熔化成形工艺参数(激光功率、扫描速度和扫描间距)对1Cr18Ni9Ti不锈钢致密度的影响,分析了各工艺参数对致密度的影响规律。结果表明,粉末熔化的能量输入密度主要取决于激光功率和扫描速度;在激光功率325~340 W、扫描速度1 000~1 200 mm/s、扫描间距0.12 mm的工艺参数下,SLM技术可制备致密度高于99.9%的1Cr18Ni9Ti不锈钢零件。采用优化后的SLM工艺参数成形1Cr18Ni9Ti不锈钢试棒的力学性能优于QJ501A-98标准,抗拉强度Rm≥709 MPa,屈服强度Rp0.2≥547 MPa,断后伸长率A≥41%。     

LNG储罐用06Ni9钢板生产工艺及控制措施

介绍了LNG储罐用06Ni9钢板的技术要求。针对生产中06Ni9钢板性能控制、表面质量控制及超极限规格轧制板形控制的难点问题，经试验及现场实践，提出了相应的控制措施，如优化化学成分设计、优化轧制工艺和热处理工艺，保证了钢板的性能；板坯表面喷涂专用防氧化涂料，并配合合理的除鳞工艺，保证了钢板的表面质量；优化坯料、辊型设计，改进模型参数，保证了极限规格钢板的板形质量。在此基础上，太钢成功开发出LNG工程用06Ni9钢板。     

Ni doped Bi2WO6 for electrochemical OER activity

Due to over depletion of fossil fuels, researchers started to find hydrogen energy to compete with the energy demands. Bi₂WO₆ and Ni (5% and 10%) doped Bi₂WO₆ were prepared via hydrothermal route. Structural confirmation of undoped and doped Bi₂WO₆ nanostructures was estimated by using standard characterization studies. The nanoflake and nanoneedle like morphology of undoped and Ni doped Bi₂WO₆ was confirmed in nanoscale range. The highest OER activity was achieved for 10% Ni doped Bi₂WO₆ nanostructure electrode with the excellent current density of 272 mA/g with overpotential of 242 mV in the fabricated three electrode half cell set up. The higher electron transport offered by Ni ions to Bi₂WO₆ host has been reported with the electrochemical mechanism. Hence, the unusual robust electrodes for electrochemical potential applications by tuning its property via suitable foreign ion dopant could be the great beginning of this recent year research. In such a way, this work would be the better way of swapping of nobel metal catalysts for electrochemical OER activity.     

Ni–Fe nanocubes embedded with Pt nanoparticles for hydrogen and oxygen evolution reactions

Electrochemical water-splitting is widely regarded as one of the essential strategies to produce hydrogen energy, while Metal-organic frameworks (MOFs) materials are used to prepare electrochemical catalysts because of its controllable morphology and low cost. Herein, a series of trimetallic porous Pt-inlaid Ni–Fe nanocubes (NCs) are developed with bifunctions of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In the process of prepare the electrochemical catalysts, Pt nanoparticles are uniformly embedded in the Fe–Ni PBA cube structure, and ascorbic acid is employed as a reducing agent to reduce Pt²⁺ to Pt nanoparticles. In this work, the cubic structure of Fe–Ni PBA is maintained and the noble metal Pt nanoparticles are embedded. Remarkably, the formation of PBA cubes, Pt inlay and reduction are completed in one step, and Pt nanoparticles are embedded by a simple method for the first time. By employing acid etching method, a porous structure is formed on the PBA cube, which increases the exposed area of the catalyst and provides more active sites for HER and OER. Due to the porous structure, highly electrochemical active surface area and the embedded of highly dispersed Pt nanoparticles, the porous 0.6 Ni–Fe–Pt nanocubes (NCs) exhibits excellently electrocatalytic performance and durable stability to HER and OER. In this work, for HER and OER, the Tafel slopes are 81 and 65 mV dec⁻¹, the overpotential η at the current density of 10 mA cm⁻² are 463 and 333 mV, and the onset potential are 0.444 and 1.548 V, respectively. And after a 12-h i-t test and 1000 cycles of cyclic voltammetry (CV), it maintained high stability and durability. This work opens up a new preparation method for noble metal embedded MOF materials and provided a new idea for the preparation of carbon nanocomposites based on MOF.     

In situ direct growth of flower-like hierarchical architecture of CoNi-layered double hydroxide on Ni foam as an efficient self-supported oxygen evolution electrocatalyst

Exploring economical, efficient and robust electrocatalysts toward the oxygen evolution reaction (OER) is one of the key issues in water splitting technology. Nanostructure engineering of electrocatalysts and hybridizing active species with a conductive support represent powerful strategies to enhance the electrocatalytic performance. Herein, we report a facile one-step solvothermal method to directly grow 3D CoNi-layered double hydroxide (LDH) flower-like architectures onto porous and conductive Ni foam (NF) substrate (denoted as CoNi-LDH(2:1)@NF hereafter). The flower-like hierarchical architecture of CoNi-LDHs with open configurations endows CoNi-LDH microflowers with sufficient accessible active sites and efficient mass diffusion paths. Moreover, the in situ direct growth manner ensures an intimate contact between the electroactive CoNi-LDHs and NF substrate and thus the charge transfer resistance is reduced. Consequently, the as-formed self-supported and binder-free electrode of CoNi-LDH(2:1)@NF exhibits an outstanding OER performance with a small overpotential of 283 mV at a relatively large current density of 50 mA cm⁻² and a remarkable long-term electrochemical durability in 0.1 M KOH solution, holding great promise in practical scale-up water electrolysis. The present study may open a new avenue to design and fabricate cost-effective and high-efficiency electrocatalysts for energy conversion applications.     

Aid of a metallic functional layer on Ni/YSZ anode for Direct Methane Fuel Cell

Aid of a metallic overlayer to nickel/yttrium-stabilized-zirconia (Ni/YSZ) anode is investigated in Direct Methane Fuel Cell. Copper modified nickel metallic overlayer shows high activity for fuel cell performance and good stability to coking in methane atmosphere. The copper-nickel overlayer provides advantages of material compatibility with the substrate and catalytic function on copper-modified nickel sites. The results suggest that the overlayer is effective for decomposition of methane and tolerant to coking by removal of deposited carbon via oxidation and gasification reaction.     

Self-supported multidimensional Ni–Fe phosphide networks as novel and robust water splitting catalyst

The water splitting has become one of the most promising hydrogen production methods. The Ni–Fe–P materials were first synthesized and in situ grown on nickel foam by typical hydrothermal and phosphating methods. The Ni–Fe–P-300 catalyst shows excellent water splitting activity (cell voltage of 1.59 V @10 mA cm⁻²) and stability after phosphating. The results of density functional theory (DFT) demonstrate that the water molecules preferentially adsorbed on the Fe site and Fe might be the real catalytic active site. A series of characterization indicated that a small amount of phosphorus loss was probably caused on the catalyst surface, but the electrocatalytic activity was not affected by the small amount of oxide species formation. This study offers a promising way to design and optimize electrocatalysts for the water splitting in alkaline solution.     

Effects of Sn doping on the manufacturing,performance and carbon deposition of Ni/ScSZ cells in solid oxide fuel cells

This work demonstrates the effect of tin (Sn) doping on the manufacturing, electrochemical performance, and carbon deposition in dry biogas-fuelled solid oxide fuel cells (SOFCs). Sn doping via blending in technique alters the rheology of tape casting slurry and increases the Ni/ScSZ anode porosity. In contrast to the undoped Ni/ScSZ cells, where open-circuit voltage (OCV) drops in biogas, Sn–Ni/ScSZ SOFC OCV increases by 3%. The maximum power densities in biogas are 0.116, 0.211, 0.263, and 0.314 W/cm² for undoped Ni/ScSZ, undoped Ni/ScSZ with 3 wt% pore former, Sn–Ni/ScSZ and Sn–NiScSZ with 1 wt% pore former, respectively. Sn–Ni/ScSZ reduces the effect of the drop in the maximum power densities by 26%–36% with the fuel switch. A 1.28–2.24-fold higher amount of carbon is detected on the Sn–Ni/ScSZ samples despite the better electrochemical performance, which may reflect an enhanced methane decomposition reaction.     

Electrochemical fabrication of Ni–Mo nanostars with Pt-like catalytic activity for both electrochemical hydrogen and oxygen evolution reactions

Synthesis of electrocatalysts with excellent performance for hydrogen and oxygen evolution are the main challenges for production of hydrogen by electrochemical water splitting method. Here, Ni–Mo nanostars were created by electrochemical deposition process at different morphologies and their electrocatalytic behavior was studied for hydrogen and oxygen evolution reactions in 1.0 M KOH solution. Increased electrochemically active surface area due to the nanostars formation, improved intrinsic electrocatalytic activity, increased surface wettability, as well as being binder-free during electrode production, resulted in excellent electrocatalytic behavior. For optimized condition, 60 mV and 225 mV overpotential are needed for generating the current density of 10 mA.cm-² in HER and OER process respectively in the alkaline medium. The lower slope of the electrode compared to the other electrodes also indicated that the kinetics of HER on the surface of the electrode was better. Also, there was very little change in the potential during the stability test, indicating the excellent electrocatalytic stability of the synthesized electrode. The present study introduces a rational, cost-effective and binder-free method for the synthesis of high performance electrocatalysts.     

Effect of active site and charge transfer on methane dehydrogenation over different Co doped Ni surfaces by density functional theory

To uncover the effects and the underlying mechanisms of Co content on CH₄ dehydrogenation over Ni–Co bimetal catalyst, the CH₄ successive dehydrogenation process over Ni (111) and different Co doped Ni (111) surface has been systematically studied via DFT calculation. Active sites and electronic properties have been obtained. CH₄ physically located at the top site of Ni or Co, while other CH_x species preferably occupied the threefold site. Besides, the charge transferred from surface to absorbates and the p-band center of absorbates could well describe the adsorption strength of CH_x and the activation barrier of CH dehydrogenation on different surfaces. More importantly, the addition of small Co could improve the resistance to carbon deposition by weakening the adsorption of C, suppressing the activity of CH₄ dehydrogenation and promoting C hydrogenation process.