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1.
Tian Xie Haixia Zhao Zunhang Lv Guangwen Xie Yan He 《International Journal of Hydrogen Energy》2021,46(1):581-588
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). 相似文献
2.
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。 相似文献
3.
目的 提高涂层刀具在高速工况下的切削寿命。方法 利用电弧离子镀技术在高速钢试样块和刀具表面制备不同弧电流(60、80、100 A)的AlCrBN涂层。采用扫描电镜(SEM)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)、轮廓仪、洛氏压痕仪、划痕仪、显微硬度计、球盘摩擦磨损试验仪和切削试验对涂层的微观结构和性能进行研究分析。结果 AlCrBN涂层的物相成分为固溶的fcc-(Cr,Al)N相以及少量的CrB2和fcc-BN相。随着AlCrB靶弧电流由60 A增至100 A,表面粗糙度Sq值由197 nm增至208 nm,Sa值由107 nm增至113 nm;显微硬度由3574HK0.05先增至3890HK0.05,再降至3209HK0.05;结合强度Lc2由57 N增至63 N,再降至55 N,均呈现先增后减的趋势。不同弧电流制备的AlCrBN涂层的磨损率依次为0.69×10-15、0.38×10-15、0.84× 10-15 m3/(N?m),涂层的磨损机理均为磨粒磨损、粘着磨损和氧化磨损。切削结果显示,AlCrBN涂层刀具在切削速度VC为60 m/min和191 m/min条件下的切削寿命均高于AlCrN涂层刀具,且80 A条件下制备的AlCrBN涂层刀具切削寿命均最长,分别为9 m和6 m。切削速度60 m/min条件下的磨损机理:初期为磨粒磨损,中期为磨粒磨损和粘着磨损,后期为粘着磨损。切削速度191 m/min条件下的磨损机理:初期和中期为磨粒磨损和粘着磨损,后期为粘着磨损。结论 AlCrBN涂层刀具与AlCrN涂层刀具相比,切削性能更加优越,并且80 A条件下制备的AlCrBN涂层的综合性能最优。 相似文献
4.
利用多弧离子镀-磁控溅射复合技术通过改变脉冲偏压在Si片与SS304基体表面制备了TiAlCN薄膜,研究了不同脉冲偏压对薄膜结构和力学性能的影响。薄膜成分、表面形貌、相结构及力学性能分别利用能量弥散X射线谱(EDS)、扫描电镜(SEM)、X射线衍射(XRD)和纳米压痕仪等设备进行表征。结果表明,随着脉冲负偏压的增加,薄膜中Ti元素的含量先减小后增大,而Al元素有相反的变化趋势。适当增大脉冲偏压,薄膜表面颗粒、凹坑等缺陷得到明显改善。物相分析表明TiAlCN薄膜主要由(Ti,Al)(C,N)相,Ti4N3-x相和Ti3Al相组成。薄膜平均硬度与弹性模量随脉冲负偏压的增加先增大后减小,在负偏压-200 V时达到最大值分别为36.8 GPa和410 GPa。 相似文献
5.
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. 相似文献
6.
在45钢表面电刷镀得到三价铬镀层,镀液组成和工艺条件为:Cr2(SO4)36H2O 0.4 mol/L,甲酸铵0.5 mol/L,氨基乙酸0.5 mol/L,H3BO30.6 mol/L,NaH2PO2 H2O 0.3 mol/L,pH=1.5,温度50°C,镀笔移动速率15 cm/s。研究了电压对镀铬层显微结构、表面粗糙度、厚度、显微硬度和耐磨性的影响。随电压增大,镀层厚度增大,显微硬度和耐磨性均先提高后降低。电压为14 V时,镀层的表面平整,粗糙度为2.387μm,显微硬度为602 HV,耐磨性最好。 相似文献
7.
《International Journal of Hydrogen Energy》2020,45(12):7412-7422
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. 相似文献
8.
《Ceramics International》2021,47(18):25287-25295
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. 相似文献
9.
在缸套表面进行镍磷复合镀强化处理,可以提高湿式内燃机缸套耐腐蚀性能,但会增加产品的成本。研究了在普通贝氏体气缸套材料基础上去掉贵重金属镍,调整其他成分比例,在确保材料性能不变的前提下,降低产品的成本。结果表明,配合表面强化处理,缸套硬度高、耐腐蚀强、生产成本低,并可以延长发动机寿命。 相似文献
10.
目的通过电弧离子镀技术,获得抗氧化性能优良的NiAl涂层。方法采用电弧离子镀技术,在弧流为110 A,偏压为-50 V的参数下沉积NiAlHf涂层。通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)对涂层的物相结构和形貌进行分析,通过能谱仪(EDS)分析涂层的成分。采用恒温氧化增重实验对涂层的氧化动力学进行分析。结果由电弧离子镀技术制备的NiAl涂层致密均匀,无大颗粒、孔洞等缺陷。涂层主要由β-NiAl相组成,活性元素Hf固溶在主相中。NiAlHf涂层表现出良好的抗高温氧化性能,动力学曲线符合抛物线规律,在1150℃下恒温氧化200h的平均氧化速率为0.0841g/(m^2×h),远优于传统MCrAlY涂层体系。NiAlHf涂层在氧化初期形成保护性的α-Al2O3氧化皮以及少量亚稳态的θ-Al2O3,随后θ-Al2O3逐渐转变为稳态的α-Al2O3。Hf在涂层表面富集从而形成HfO2,对氧化皮形成了钉扎作用,增强了氧化皮的粘附性,提高了涂层的抗氧化性能。随着氧化的进行,涂层中的β-NiAl相逐渐转变为γ'-Ni3Al相。结论 NiAlHf涂层在1150℃下仍具备优良的抗高温氧化性能,对下一代耐更高温度涂层开发,电弧离子镀NiAl涂层的技术推广及工业化应用有一定的指导作用。 相似文献