激光扫描速率对Ni／Cr3C2复合涂的影响

研究了在不同的激光扫描速度下对45^#钢表面进行Ni/Cr3C2激光熔覆,工对合金组织,显微硬度和物相进行了分析,结果表明,激光扫描度对Ni/Cr3C2合金层的组织和显微硬度有很大的影响。     

碳钢表面激光熔敷Ni基Cr3C2／（Ni＋Cr）复合涂层的研究

使用2kw连续波CO2激光器在45^#钢表面进行激光熔敷Ni合金中添加50wt%Ni Cr包敷的Cr3C2复合粉的复合少层，并对激光熔敷层的晶体生长形态、物相和硬度进行了分析。结果表明：熔敷层由下至上可分为平面前沿生长区，胸状晶区及枝晶：熔敷区的近表层由高度细小的奥氏体枝晶和C7C3、Cr3C2等物组成，熔敷层的硬度平均高达HV0.2950-1200。添加Cr3C2粒子的激光熔敷层的显微硬度比镍基合金的显微硬度平均提高了HV0.2300。     

汽轮机末级叶片激光熔覆的研究

以Nb、Ti、Si合金粉末(at%61:21:18)为原料,在汽轮机末级叶片材料Ti-6Al-4V(TC4)合金表面进行激光熔覆,应用OM、XRD、SEM、EDS和EMPA等方法分析了涂层的显微组织,测试了涂层的显微硬度。结果表明:激光熔覆涂层的组织是在共晶连续固溶体(Nb,Ti)ss弥散分布着Nb3Si和Ti5Si3颗粒,涂层的显微硬度在HV960-1000之间,比基体合金提高了近3倍。     

激光表面熔凝处理对30Cr2Ni4MoV转子钢高温水腐蚀性能的影响

进行了三种强度级别的30Cr2Ni4MoV钢的激光表面熔凝处理,用电化学极化曲线和高温应力腐蚀试验考察了其耐腐蚀性能。研究表明:激光熔凝处理后在30Cr2Ni4MoV表面形成了约10~20μm的致密马氏体硬化层和压应力状态,基材状态对激光熔凝硬化层的性能无明显影响,但激光功率增大会导致表面熔凝层硬度水平降低;激光表面熔凝处理使腐蚀电位左移,腐蚀电流密度减小,抗腐蚀性能明显增强。     

20G钢管表面激光熔覆非晶合金复合涂层的耐腐蚀性能试验研究

利用激光熔覆技术在20G钢表面熔覆合金涂层,分析了激光熔覆层的微观组织,利用高温腐蚀试验和烟气模拟腐蚀试验测试激光熔覆层的耐腐蚀性能。结果表明：细小晶粒与有较高韧性的非晶相夹杂并弥散于金属间化合物的复合组织具有良好的抗高温腐蚀、抗烟气腐蚀性能,可应用于垃圾焚烧锅炉受热面,改善其表面的耐腐蚀性能。     

激光处理的等离子喷涂Cr2O3涂层的摩擦学特性

通过对等离子喷涂涂层在Ｎｄ－ＹＡＧ激光处理前和处理后的磨损量对比，研究了激光处理对等离子喷涂Ｃｒ２Ｏ３陶瓷薄涂层的影响，为此，用陶瓷／ＳＡＥ４６２０钢以线接触配对进行了环形试样磨损试验，还讨论了磨损机制和因激光处理引起的涂层中有关孔隙率，显微结构和涂层结合情况的变化。     

化学成分对1Cr 17Ni2钢金相组织和力学性能的影响

引进型的电站泵平衡鼓等零件采用１Ｃｒ１７Ｎｉ２钢制造。国产的１Ｃｒ１７Ｎｉ２钢的含镍量低,导致金相组织有大量的铁素体,从而影响力学性能,通过调整热处理工艺使材料达到了设计规定的技术要求。表７参２     

热处理工艺对CuNiIn涂层硬度的影响

研究了不同的热处理工艺对超音速火焰喷涂（HVAF）CuNiIn涂层显微硬度的影响。结果表明：HVAF涂层通过600℃去应力回火,可使硬度显著降低至HV150左右,并消除了压痕裂纹现象,恢复了该合金低硬度高塑性的本来面貌。     

Ga doped Ni3S2 ultrathin nanosheet arrays supported on Ti3C2-MXene/Ni foam: An efficient and stable 3D electrocatalyst for oxygen evolution reaction

Exploring cost-efficient electrocatalysts for oxygen evolution reaction (OER) is still a huge challenge in the electrochemical energy conversion technology. In this work, Gallium (Ga)-doped Ni₃S₂ nanosheet arrays grown on Ti₃C₂-MXene/nickel foam (Ga–Ni₃S₂/Ti₃C₂/NF) have been synthesized by a successive hydrothermal and sulfidization process. The Ga doping modulates the electronic structure of Ni₃S₂, so tuning the adsorption energies of oxygen intermediate (1OOH). The Ga–Ni₃S₂/Ti₃C₂/NF delivers outstanding catalytic activities toward OER with an overpotential of 340 mV at 100 mA cm^?2, and exhibits superior electrochemical durability. The excellent OER performance of Ga–Ni₃S₂/Ti₃C₂/NF can be ascribed to the 3D sheet arrays morphology and optimized electronic structure. Density functional theory (DFT) calculations also demonstrate that electronic disturbance attributed to Ga doping effectively improves the activity of Ni sites, leading to stronger binding strength of 1OOH intermediate at Ni sites nearby Ga. This study provides insights into the fabrication of advanced electrocatalysts for application.     

基于三维激光扫描的隧道变形特征分析

鉴于地震条件下二古溪隧道坡体震裂损伤情况,再加上降雨和蓄水的耦合作用,导致坡体出现大变形,造成坡脚二古溪隧道挤压、剪切破坏的问题,基于三维激光扫描技术获取隧道点云影像特征,掌握了隧道全长变形情况,得到隧道变形量值。对比多次扫描得到的隧道变形数据,并分析其影响因素,结果表明,该研究为隧道的变形监测提供了一种方法和手段。     

三维激光雷达扫描技术在河流模拟中的应用

三维激光雷达扫描技术以精度高、测量速度快的特点被应用于多个行业。为快速获取河道流场结构,开展60°弯道动床模型试验,探索采用激光雷达扫描技术获得河床数字地形,以激光扫描数字地形和水准测量地形为边界开展水流数值模拟,并将模拟值与试验测量值进行对比分析。结果表明,流场数值模拟结果与试验值吻合较好。沙波地形的精度对纵向时均流速、水深平均流速影响有限,但对河床切应力及断面流场结构影响明显。将激光雷达扫描技术和数值模拟技术相结合,既能获得高精度的河床数字高程和精细水流流动结构,又可大大缩短试验流场测量周期。     

Aqueous-phase reforming of n-BuOH over Ni/Al2O3 and Ni/CeO2 catalysts

The aqueous-phase reforming (APR) of n-butanol (n-BuOH) over Ni(20 wt%) loaded Al₂O₃ and CeO₂ catalysts has been studied in this paper. Over 100 h of run time, the Ni/Al₂O₃ catalyst showed significant deactivation compared to the Ni/CeO₂ catalyst, both in terms of production rates and the selectivity to H₂ and CO₂. The Ni/CeO₂ catalyst demonstrated higher selectivity for H₂ and CO₂, lower selectivity to alkanes, and a lower amount of C in the liquid phase compared to the Ni/Al₂O₃ sample. For the Ni/Al₂O₃ catalyst, the selectivity to CO increased with temperature, while the Ni/CeO₂ catalyst produced no CO. For the Ni/CeO₂ catalyst, the activation energies for H₂ and CO₂ production were 146 and 169 kJ mol⁻¹, while for the Ni/Al₂O₃ catalyst these activation energies were 158 and 175 kJ mol⁻¹, respectively. The difference of the active metal dispersion on Al₂O₃ and CeO₂ supports, as measured from H₂-pulse chemisorption was not significant. This indicates deposition of carbon on the catalyst as a likely cause of lower activity of the Ni/Al₂O₃ catalyst. It is unlikely that carbon would build up on the Ni/CeO₂ catalyst due to higher oxygen mobility in the Ni doped non-stoichiometric CeO₂ lattice. Based on the products formed, the proposed primary reaction pathway is the dehydrogenation of n-BuOH to butaldehyde followed by decarbonylation to propane. The propane then partially breaks down to hydrogen and carbon monoxide through steam reforming, while CO converts to CO₂ mostly through water gas shift. Ethane and methane are formed via Fischer-Tropsch reactions of CO/CO₂ with H₂.     

Steam reforming of acetic acid using Ni/Al2O3 catalyst: Influence of crystalline phase of Al2O3 support

Ni-based catalysts supported on various alumina supports with different crystalline phases (γ-, α-, θ- and δ-Al₂O₃) were prepared and the effects of crystalline phases on the catalytic performance towards acetic acid steam reforming (AASR) were investigated. An acetic acid conversion of nearly 100% was observed in all the four catalysts, and their hydrogen selectivities were in the following order: Ni/α-Al₂O₃ (90%) > Ni/γ-Al₂O₃ (79%) > Ni/δ-Al₂O₃ (53%) > Ni/θ-Al₂O₃ (25%). Using different characterization methods, the inner relationship between catalyst crystalline phase and catalytic properties was determined. Through TEM, H₂-TPR and XPS characterization, Compared with α-Al₂O₃, on the surface of other crystalline phases of Al₂O₃ support were formed NiAl₂O₄ which indicated stronger interaction intensity between these supports and Ni., and that would reduce the formation of metallic Ni. It was confirmed that metallic Ni played a core role of catalytic AASR. More metallic Ni content caused better CC bonds and CH bonds breaking capability and eventually enhanced the selectivity towards hydrogen. That would be the key reason for Ni/α-Al₂O₃ showed best hydrogen selectivity among these four catalysts.     

MIL-101(Cr)-NH2/CaCl2复合材料的热化学蓄热性能研究

将金属有机骨架MIL-101(Cr)-NH₂与CaCl₂通过浸渍的方法复合得到MIL-101(Cr)-NH₂/CaCl₂热化学蓄热复合材料。采用X射线衍射分析仪（XRD）、扫描电子显微镜（SEM）、能谱分析（EDS）、全自动比表面积及孔径分析仪以及同步热分析仪（TG-DSC）等分析了复合材料的表观形貌、盐含量、比表面积和蓄热密度等参数。结果显示,复合材料的盐含量为49%,在30℃、32%湿度下的最大吸水量为0.54 g(H₂O)/g(样品),蓄热密度达到了1 204 kJ/kg,并且在经历了17次吸附-解吸循环后,其蓄热密度仅降低了6.5%,表现出优异的循环稳定性,出色的吸附性能表明这一新型复合材料在太阳能蓄热领域具有广阔的应用前景。     

Influence of La2O3 addition on activity and coke formation over Ni/SiO2 for acetic acid steam reforming

The influence of the addition amount of lanthanum oxide on the activity and coke formation over Ni/SiO₂ catalyst for hydrogen production from AcOH steam reforming was studied in the paper. Through the catalyst characterization and experimental research, it was found that with the addition of La₂O₃ the particle size of the active metal Ni decreased, and the active Ni-support interaction was enhanced. With the optimal addition amount of La₂O₃ (30 wt %), Ni/30LaSi catalyst displayed the highest activity with the high carbon conversion rate of 98.8%. The surface morphology and thermogravimetric analysis of the spent catalyst revealed that the carbon deposition was mainly in the form of filamentous coke and the diameter of the carbon fiber was related with the Ni particle size. The addition of suitable La₂O₃ can inhibit the formation of carbon deposition, decrease the content of encapsulating coke, and improve the catalyst stability.     

17Cr2Ni2MoA渗碳淬火回火的工艺研究

采用小滴量滴注法，对17Cr2Ni2MoA渗碳淬火回火工艺进行了研究，总结出了渗碳工艺，淬火回火工艺。确认通氮气排出炉内的空气能缩短渗碳时间，采用金相组织法估测硬化层深度和碳化物的状况。