三聚硫氰酸单钠盐的制备及应用研究进展

三聚硫氰酸单钠盐是一种新型的多官能团化精细化学品。介绍了三聚硫氰酸单钠盐的制备方法,以及其在橡胶硫化、橡胶与金属的硫化粘合等领域的应用研究进展。     

Fabrication of bacterial cellulose with high efficient loading of Ag and TiO2 nanoparticles for removing organic dyes

As a new advanced oxidation technology, photocatalytic technology has broad application prospects in the field of wastewater treatment. However, in the actual use process, there will be difficulties in catalyst recovery and reuse. This article successfully prepared bacterial cellulose (BC) loaded silver and titanium dioxide nanoparticles (Ag-plated TiO₂/BC composite pellicle) by in situ embedding method. BC not only works as the carrier to load TiO₂ and Ag NPs but also adsorbs dyes to promote the reaction. As a reusable photocatalytic film, it is convenient to use and recycle in terms of testing and characterization compared with powders. The results show that Ag and TiO₂ nanoparticles were closely embedded in BC. We evaluated the photocatalytic degradation performance of the catalyst on methylene blue (MB), active red X-3B, and Rhodamine B. When the reaction time was 2 h, the dye removal rates were 71%, 68%, and 82.6%. At the same time, through the inhibition zone experiment, it was found that the material has a certain inhibitory effect on both Escherichia coli and Staphylococcus aureus. Therefore, the supported catalyst prepared by this method has the advantages of high catalytic activity, relatively stable property, easy recovery, and tailorability, making it potentially applicable in sewage post-treatment links.     

熔融制样-X射线荧光光谱法测定硅质、铝质、镁质和铬质耐火材料中15种组分

硅质、铝质、镁质和铬质耐火材料中MgO、Na₂O、Fe₂O₃、MnO、Cr₂O₃、TiO₂、P₂O₅、SiO₂、CaO、K₂O、Al₂O₃等组分含量的分析,一般采用EDTA滴定法、分光光度法、原子吸收光谱法测定,操作繁琐,耗时长;而使用X射线荧光光谱法分析时,4种基体的耐火材料需要采用不同的熔融方法和校准曲线。为了将4种基体的耐火材料统一制样方法,并使用同一组校准曲线同时测定MgO、ZrO₂、Na₂O、ZnO、NiO、Fe₂O₃、MnO、Cr₂O₃、V₂O₅、TiO₂、P₂O₅、SiO₂、CaO、K₂O、Al₂O₃等主次组分,实验选用3套国外耐火材料标准样品,并对熔融温度、时间、稀释比等熔融制样条件进行优化;通过峰位及强度扫描确定各元素电压、电流、准直器等条件,达到灵敏度与分辨率最佳,通过扫描PHA确定脉冲宽度,提高准确度。理论α系数校正元素间吸收增强效应,用比例法计算校正谱线重叠,优化校准曲线,提高分析方法准确度。各组分校准曲线线性相关系数R²在0.9940~0.9999之间。按照实验方法熔融JRRM507、JRRM803、JRRM129 3个标准样品,进行方法精密度和熔片精密度试验,结果表明重复性均能达到GB/T 21114—2007要求。按照实验方法选择镁铬矿、高岭土、铝土矿3类标准物质进行正确度验证,VS P14/3、UNS KK、ZBK394标准物质中MgO、ZrO₂、Na₂O、ZnO、NiO、Fe₂O₃、MnO、Cr₂O₃、V₂O₅、TiO₂、P₂O₅、SiO₂、CaO、K₂O、Al₂O₃等主次组分的测定结果与认定值相吻合。     

镀液温度实时控制系统的设计与实现

针对镀液温度变化的非线性和滞后性,设计了采用专家规则的镀液温度实时控制系统。该系统在实时监测的基础上,构建了综合评判镀液温度偏差和镀液温度偏差变化率的专家规则,实现了镀液温度的自适应快速调节。仿真分析结果表明,该系统克服了非线性和滞后性的不良影响,能够实现镀液温度的实时控制。     

SiC nanoparticles incorporation in electroless NiP-Graphene oxide nanocomposite coatings

The presence of SiC nanoparticles within the Graphene oxide (GO) incorporated electroless deposited NiP layers (NiP-GO) on carbon steel substrate was studied in this work. The effect of co-deposition of GO nanoplatelets and/or SiC nanoparticles on the morphology and structure of the heat-treated NiP coatings were investigated by scanning electron microscope and X-ray diffraction, respectively. The results revealed that the heat-treated NiP and NiP–SiC coatings consisted of Ni and Ni₃P phases, whereas the NiP-GO also contains the intermediated Ni₂P and Ni₁₂P₅ metastable phases due to the incomplete precipitation of Ni₃P. Such metastable phases are significantly decreased by the incorporation of SiC nanoparticles in NiP-GO coatings. The mechanical properties of the coatings were characterized by microhardness measurement and “pin on disk” wear test. The corrosion tests were conducted in aqueous 3.5 %wt NaCl using electrochemical measurement for Ni–P, NiP-GO, NiP–SiC, and NiP-GO-xSiC coatings. By co-deposition of SiC nanoparticles, the hardness of NiP-GO is significantly increased and the wear loss is reduced, especially at a high sliding distance during the wear test. The corrosion behavior of the NiP-GO coatings containing different amounts of SiC nanoparticles has been investigated.     

A highly active composite electrocatalyst Ni–Fe–P–Nb2O5/NF for overall water splitting

This work demonstrates a facile Nb₂O₅-decorated electrocatalyst to prepare cost-effective Ni–Fe–P–Nb₂O₅/NF and compared HER & OER performance in alkaline media. The prepared electrocatalyst presented an outstanding electrocatalytic performance towards hydrogen evolution reaction, which required a quite low overpotential of 39.05 mV at the current density of ?10 mA cm^?2 in 1 M KOH electrolyte. Moreover, the Ni–Fe–P–Nb₂O₅/NF catalyst also has excellent oxygen evolution efficiency, which needs only 322 mV to reach the current density of 50 mA cm^?2. Furthermore, its electrocatalytic performance towards overall water splitting worked as both cathode and anode achieved a quite low potential of 1.56 V (10 mA cm^?2).     

Pre-activation of SBA-15 intermediate barriers with Pd nuclei to increase thermal and mechanical resistances of pore-plated Pd-membranes

Thermal and mechanical resistances of palladium composite membranes prepared by Electroless Pore-Plating (ELP-PP) and containing SBA-15 as intermediate layer were improved by doping the silica material with Pd nuclei before its incorporation on the composite membrane. Textural properties of synthesized SBA-15 materials (both raw and doped ones) were analyzed by XRD, N₂ adsorption-desorption at 77 K and TEM, while the main properties of the composite membrane were determined by SEM and gravimetric analyses. Moreover, membrane permeation tests were also carried out with pure gases, hydrogen and nitrogen, and binary mixtures of them at temperature of 400 °C and pressure driving forces in the range of 0.5–2.5 bar. The use of bare SBA-15 intermediate layer leads to the appearance of cracks on the Pd layer during permeation experiments at high temperature. In contrast, the use of Pd-doped SBA-15 particles avoids this problem, thus improving both thermal and mechanical resistances of the composite ELP-PP Pd-membrane. Following this preparation method, an estimated Pd thickness of 7.1 μm was obtained, reaching a hydrogen permeance of 3.81·10^?4 mol s^?1 m^?2 Pa^?0.5 and ensuring an ideal H₂/N₂ separation factor higher than 2550 at 400 °C.     

1000WN挖泥泵高铬叶轮铸造过程质量控制

介绍了1000WN挖泥泵高铬叶轮的铸造过程。通过对叶轮铸造工艺设计与模拟分析,制定出了合理的铸造工艺;利用发热冒口进行高效能补缩,结合合理的退火、淬火工艺,严格生产过程质量控制,防止缩松、裂纹缺陷的产生,成功生产出了φ2500 mm,10.5 t的高铬叶轮。为大型挖泥泵高铬叶轮的国产化制造提供借鉴。     

Coating the porous Al2O3 substrate with a natural mineral of Nontronite-15A for fabrication of hydrogen-permeable palladium membranes

Substrate surface modification is a key pretreatment during fabrication of composite palladium membranes for hydrogen purification in hydrogen energy applications. The suspension of a natural porous material, Nontronite-15A mineral, without any organic additives was employed in dip-coating of the porous Al₂O₃ substrate. The Nontronite-15A mineral was characterized by SEM, XRD, TG−DSC and granulometry analysis. The surface and cross-section of the coated porous Al₂O₃ tubes were observed by SEM, and their pore size distribution and nitrogen flux were also measured. Palladium membranes were fabricated over the coated Al₂O₃ tubes by a suction-assisted electroless plating. The optimal loading amount of the Nontronite-15A mineral is just to fill in and level up the surface cavities of the Al₂O₃ substrate rather than to form an extra continuous layer. A thin and selective palladium membrane was successfully obtained, and its permeation performances were tested. The kinetic analyses on the hydrogen flux indicate that the hydrogen permeation behavior exhibits typical characteristics for most of the palladium membranes. During the stability test at 450 °C for 192 h, no membrane damage was detected, and the hydrogen flux increased slightly.     

Enhancement of oxidation and wear resistance of Fe-based amorphous coatings by surface modification of feedstock powders

Surface oxidation of the in-flight powders during the preparation of amorphous coatings in high velocity oxygen fuel process causes the formation of oxygen-rich intersplat regions. These regions are brittle in nature and can dramatically deteriorate the mechanical performance of the coatings. To solve this problem, the starting FeCrMoCBY amorphous feedstock powders were modified by electroless plating a thin layer of Ni–W–P amorphous phase. It was found that the covering of the Ni–W–P layer can significantly reduce the oxygen content in the resultant Fe-based amorphous coatings. The wear resistance of the coatings with and without the modification of Ni–W–P thin layer was comparatively studied by ball-on-disk wear tests against Si₃N₄ counterpart in air. It revealed that the wear of two types of coatings follows the same oxidation wear mechanism but the modified coating exhibits much better wear resistance due to the improved oxidation resistance.