分级多孔金-铜薄膜对苯甲醇的催化氧化

采用合金/去合金法，在金-铜合金线表面制备了分级多孔金-铜薄膜结构(Hierarchically porous Au-Cu thin films，HPAFs)。该分级多孔结构是由微米级的大尺寸孔道-系带和纳米级小尺寸系带-孔道构成。通过对电沉积、退火处理及腐蚀条件的控制可以调控表面多孔薄膜层的厚度、结构以及组成。研究结果表明，脱合金处理残留的铜在富金的系带上形成了金主导的AuCu合金-CuO_x异质结构，其可以有效地促进分子氧的活化，而分级多孔结构有利于反应物分子在孔内的扩散传质，从而赋予HPAFs催化剂对苯甲醇分子氧氧化反应高催化活性。     

不同钙合金对钢液脱砷作用的实验研究

为了充分利用我国含砷铁矿资源，采用精炼渣+不同Ca合金对钢液进行脱砷研究，获得较高的脱砷率，其中Si-Ca-Ba合金综合脱砷效果最佳。在相同操作条件下，通过改变实验条件，对钢液中砷含量随时间变化规律以及对脱砷效果的影响进行研究，并对高砷含量下不同Ca合金加入钢液后Ca的有效利用率进行详细分析。     

2021 年 2 期目录

β钛合金因其具有良好的生物相容性和耐磨性而被用作硬组织的替代物。对钛合金植入体进行表面改性可以保证材料的整体强度和弹性模量,同时使其与人骨接触部位能够呈现低弹性模量特性。选用Ti-40Nb合金作为基体材料,采用磁控溅射与去合金化相结合的表面改性工艺获得表面纳米多孔结构,并对纳米多孔结构进行微观组织表征和力学性能测试。结果表明,在0.5% HNO₃水溶液中去合金化4 h,随后在1 mol/L KOH水溶液中去合金化12 h,能够得到微纳通透的分层多孔,多孔结构的形成使得Ti-40Nb合金表面的弹性模量达到37 GPa,接近人骨的弹性模量,避免了应力屏蔽带来的影响,同时还保证了Ti-40Nb合金的整体强度。此外,通过分析铸态和薄膜态Ti-Nb-Cu合金去合金化形成多孔结构的过程,探索两者成孔机制的区别。     

不同成分Ni-Al合金去合金化过程中的结构演化与机理

采用真空熔炼与快速凝固相结合的方法制备Ni(原子分数)为15%~40%的Ni-Al前驱体合金薄带,通过不同去合金化工艺制备纳米多孔镍,用X射线衍射仪(XRD)、扫描电镜(SEM)分析多孔镍的相组成和微观形貌,研究前驱体Ni-Al合金成分与去合金化工艺对纳米多孔镍微观结构的影响及其形成机理.结果表明:镍原子分数为15%~30%时,可通过化学去合金化形成纳米多孔Ni,镍原子分数为25%~40%时,可通过电化学去合金化形成纳米多孔结构.相同成分的Ni-Al合金,电化学去合金化较化学去合金化获得的多孔结构更为均匀,骨架尺寸相对较小.2相的协同腐蚀作用对去合金化具有促进作用,且对纳米多孔镍的形貌及多层次纳米多孔结构的形成有重要影响.     

银-铂合金表面吸附氧的热脱附谱

用热脱附谱研究了氧在银-铂合金(含Pt 9.7 at.%)表面上的化学吸附。结果表明:氧在合金表面上主要存在两种吸附状态,峰温为580±10K的二级脱附峰,与氧原子在合金表面Ag原子上的吸附相对应,脱附活化能E_d=213±15kJ/mol;峰温在660K左右的二级脱附峰,与合金表面Pt原子对氧的作用有关,脱附活化能为330～430kJ/mol,并随氧暴露量的增加而增大。     

不同脱砷剂钢液脱砷研究

为了充分利用我国含砷铁矿资源，采用CaO+CaF2、CaC2+CaF和Si-Ca-Ba合金+CaF2对钢液进行脱砷研究，获得较高的脱砷率，其中Si-Ca-Ba合金+CaF2脱砷效果最明显，其脱砷率最高可达67.7%.在相同实验操作条件下，通过实验室研究，分析比较了温度、传质系数和S含量对不同脱砷剂脱砷效果的影响.     

预变形量对Fe-19Mn和Fe-19Mn-1.5Si合金阻尼性能的影响

采用倒扭摆法评价了Fe 19Mn合金和Fe 19Mn 1.5Si合金在不同预变形量下的阻尼性能,并通过光学显微镜和X射线衍射仪分析了合金的微观组织形貌和层错几率.结果表明：预变形量小于4%时,由于Fe 19Mn和Fe 19Mn 1.5Si合金的层错数量增加而使其阻尼性能提高;预变形量在4%~10%时,Fe 19Mn合金的层错数量不断增加,但由于马氏体和层错的相互交割严重、层错和马氏体变得短小以及Shockley不全位错的脱钉运动困难,致使其阻尼性能反而下降;而由于Fe 19Mn 1.5Si中Si具有固溶强化和降低层错能的作用,合金本身的马氏体和层错较小,预变形量对其影响不大,即变形不改变Shockley不全位错的脱钉难度,故其阻尼性能继续保持稳定增长.     

锂离子电池合金负极材料研究进展

合金类材料具有高比容量和高安全性等优势,是极具潜力的锂离子电池负极材料。合金负极不同的脱嵌锂机制显著影响着锂枝晶生长、锂离子输运及体积膨胀等行为。介绍了不同合金负极的脱嵌锂机制,并从热力学、动力学角度分析了锂沉积形核过程及锂在电极内部输运过程的影响因素,总结了合金负极控制锂沉积行为及体积膨胀的研究进展和未来发展方向。     

采用混合元素法制备多孔Ni3Al材料

利用NaCl颗粒为造孔剂,通过粉末冶金方法制备多孔结构的Ni3Al合金,并采用控制升温速度和保温时间的烧结工艺,添加不同质量分数的NaCl制备Ni3Al.研究造孔剂NaCl的添加量与Ni3Al合金的孔隙度、孔隙结构之间的关系.并研究采用元素粉末法制备多孔Ni3Al合金的反应过程与孔隙形成过程.结果表明,Ni3Al的多孔结构是由真空状态下材料中添加的NaCl挥发后所形成的,添加NaCl的量对材料孔隙度和孔隙结构有显著的影响,通过调节NaCl颗粒的大小可以直接控制材料中孔隙的大小,孔隙形状与NaCl颗粒的形状一致.孔隙度随NaCl添加量的提高而提高,材料密度随NaCl添加量的提高而降低,基本呈线性关系.当采用NaCl的质量分数为50%时,得到孔隙分布均匀、孔隙无聚集的多孔Ni3Al材料.     

淮南煤矸石电解制备Al-Si-Ti合金的研究

对淮南煤矸石低温焙烧酸浸脱杂并电解制备Al—Si—Ti合金进行了研究,结果表明:采用该工艺生产Al—Si—Ti合金切实可行,关键在于煤矸石中杂质的去除.焙烧温度是影响脱杂的主要因素,在300～500℃之间能取得最佳效果,脱杂煤矸石在实验电解槽内能全部被还原并共同沉积形成合金.     

纳米多孔铜带的制备及表征

以Cu15Al85合金薄带为前驱体,采用去合金化法,制备孔结构单一、均匀且三维贯通的纳米多孔铜（NPC）,研究不同去合金腐蚀液和退火处理条件对样品微观形貌的影响。经场发射扫描电镜（FE-SEM）、X-射线衍射（XRD）和能谱仪（EDS）对 NPC 检测,结果表明：与在 w（HCl）=5%的酸性腐蚀液中自由腐蚀去合金化得到的 NPC 相比,经 w（NaOH）=5% 的碱性腐蚀形成的 NPC 的多孔结构更加完整,孔径由150 nm 减小到100 nm,孔壁由40 nm 减小到10 nm;对前躯体合金薄带进行退火处理后,去合金化形成的 NPC 多孔形貌更加完整均一,孔径尺寸由 150 nm 减小到 100 nm。     

Glass-forming ability,microhardness, corrosion resistance,and dealloying treatment of Mg60?xCu40Ndx alloy ribbons

The influence of Nd addition on the glass-forming ability (GFA), microhardness, and corrosion resistance of Mg60?xCu40Ndx (x = 5, 10, 15, 20, and 25, at%) alloys were investigated by differential scanning calorimetry, Vickers-type hardness tests, and electrochemical me-thods. The results suggest that the GFA and microhardness of the amorphous alloys increase until the Nd content reaches 20at%. The corro-sion potential and corrosion current density obtained from the Tafel curves indicate that the Mg35Cu40Nd25 ternary alloy exhibits the best corrosion resistance among the investigated alloys. Notably, nanoporous copper (NPC) was synthesized through a single-step dealloying of Mg60?xCu40Ndx (x = 5, 10, 15, 20, and 25) ternary alloys in 0.04 mol·L?1 H2SO4 solution under free corrosion conditions. The influence of dealloying process parameters, such as dealloying time and temperature, on the microstructure of the ribbons was also studied using the sur-face diffusivity theory. The formation mechanism of dealloyed samples with a multilayered structure was also discussed.     

Influences of ultrasonic irradiation on the morphology and structure of nanoporous Co nanoparticles during chemical dealloying

The Co-61.8 wt% Al nanoparticles of 45 nm were prepared by hydrogen plasma-metal reaction (HPMR) method. The nanoparticles display core shell structure with Al13Co4 and CoAl core and aluminum oxide shell (about 2 nm). Under ultrasonic irradiation, nanoporous fcc-Co nanoparticles were produced successfully by chemically dealloying the Co-Al nanoparticles at room temperature, whereas, without ultrasonic irradiation CoAl phase could hardly react with sodium hydroxide solution. At 323 K the Co-Al nanoparticles could be dealloyed to fcc-Co and hcp-Co phases even without ultrasonic irradiation. The surface area of the dealloyed nanoparticles under ultrasonic irradiation was larger than that of the dealloyed sample without ultrasonic irradiation at the same temperature. It is believed that the microjet and shock-wave induced by ultrasonic irradiation give rise to particles size reduction, interparticle collision and surface cleaning, and accelerate the dealloying process and the phase transformation.     

多孔结构对Vero White型光敏树脂力学性能的影响

多孔结构设计是影响使用性能的主要因素之一,优化多孔结构是减少质量的重要途径.利用静力学仿真分析不同板材内部结构力学性能的变化规律及特点.采用以色列Objet Eden250光固化设备,对Vero White型光敏树脂进行不同结构光固化成型,利用AG-Xplus电子万能试验机测试了试样抗压性能,并与仿真结果对比.研究结果表明,多孔结构的抗压强度随着孔隙率的升高而降低,不同结构的多孔结构的抗压强度的变化范围在15～70 MPa.蜂窝状结构的性能优于六面体结构,六面体结构优于八面体结构.研究结果与理论结果基本一致,为多孔结构在增材制造的成功应用提供了理论依据和实验依据.     

Fabrication of fine spongy nanoporous Ag-Au alloys with improved catalysis properties

Fine NP-AgAu(nanoporous AgAu) alloys with spongy structure was fabricated by chemical dealloying from rapidly solidified amorphous precursors Ag_(38.75-x)Cu_(38.75)Si_(22.5)Au_x(x=0, 0.5, 1 and 5). The results indicate that the addition of small content Au in precursor can refine both the ligaments and pores obviously. Among the present components of the precursors, NP-AgAu alloys dealloying from Ag_(37.75)Cu_(38.75)Si_(22.5)Au_1 had the finest spongy structure. The size of pores was 5–10 nm and the grain size of ligaments was 10–20 nm. It also had the highest surface area of 106.83 m~2g~(-1) and the best catalytic activity towards electro-oxidation of formaldehyde with the peak current of 665 mA mg~(-1).     

Glass-forming ability,microhardness, corrosion resistance,and dealloying treatment of Mg60-xCu40Ndx alloy ribbons

The influence of Nd addition on the glass-forming ability (GFA), microhardness, and corrosion resistance of Mg_60-xCu₄₀Nd_x (x=5, 10, 15, 20, and 25, at%) alloys were investigated by differential scanning calorimetry, Vickers-type hardness tests, and electrochemical methods. The results suggest that the GFA and microhardness of the amorphous alloys increase until the Nd content reaches 20at%. The corrosion potential and corrosion current density obtained from the Tafel curves indicate that the Mg₃₅Cu₄₀Nd₂₅ ternary alloy exhibits the best corrosion resistance among the investigated alloys. Notably, nanoporous copper (NPC) was synthesized through a single-step dealloying of Mg_60-xCu₄₀Nd_x (x=5, 10, 15, 20, and 25) ternary alloys in 0.04 mol·L-1 H₂SO₄ solution under free corrosion conditions. The influence of dealloying process parameters, such as dealloying time and temperature, on the microstructure of the ribbons was also studied using the surface diffusivity theory. The formation mechanism of dealloyed samples with a multilayered structure was also discussed.     

ZnO/Zn/CNT三维多孔复合结构的制备及对甲基橙的无光催化降解

以碳纳米管(CNTs)、纳米ZnO/Zn复合粉体和造孔剂聚甲基丙烯酸甲酯(PMMA)微球为原料,通过超声分散、真空抽滤、焙烧的方法制备ZnO/Zn/CNT三维多孔复合结构.利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、能谱仪(EDS)和拉曼光谱仪对样品的微观结构及成分进行表征.结果显示,样品内部存在大量的连通孔,ZnO/Zn复合粉体均匀分散于CNTs所构筑多孔结构的孔隙中.在多孔复合结构的制备过程中,ZnO晶体结构未发生变化也无杂质生成.多孔复合结构对模拟污染物甲基橙的暗室催化降解结果证明,由于独特的孔结构存在和ZnO与CNTs的协同作用,使得样品在80min时对甲基橙的降解率达99.9%.     

Self-supported amorphous nanoporous nickel-cobalt phosphide catalyst for hydrogen evolution reaction

Hydrogen evolution reaction(HER) through electrocatalysis using cost-efficient and long-term stable bimetallic phosphide as electrocatalyst holds a great promise for sustainable clean energy technologies. In this study, self-supported nanoporous Ni-Co-P(np-Ni-Co-P) catalyst with amorphous structure was synthesized by utilizing a facile electrochemical dealloying strategy. The results showed that due to the nanoporous structure, disorder atomic arrangement and alloying effect, the np-Ni-Co-P exhi...     

Evolution of nanoporosity in dealloying

Dealloying is a common corrosion process during which an alloy is 'parted' by the selective dissolution of the most electrochemically active of its elements. This process results in the formation of a nanoporous sponge composed almost entirely of the more noble alloy constituents. Although considerable attention has been devoted to the morphological aspects of the dealloying process, its underlying physical mechanism has remained unclear. Here we propose a continuum model that is fully consistent with experiments and theoretical simulations of alloy dissolution, and demonstrate that nanoporosity in metals is due to an intrinsic dynamical pattern formation process. That is, pores form because the more noble atoms are chemically driven to aggregate into two-dimensional clusters by a phase separation process (spinodal decomposition) at the solid-electrolyte interface, and the surface area continuously increases owing to etching. Together, these processes evolve porosity with a characteristic length scale predicted by our continuum model. We expect that chemically tailored nanoporous gold made by dealloying Ag-Au should be suitable for sensor applications, particularly in a biomaterials context.