镁合金纳米TiO2/Ni-P化学复合镀层的制备与性能研究

M—P／纳米TiO2颗粒复合镀层可在提高硬度的同时增强镁舍金的耐腐蚀性。本工作以硫酸镍为主盐对镁合金进行了纳米TiO2／Ni—P复合镀，并用金相法、扫描电镜（SEM）、X射线能谱（EDS）、动电位扫描等手段研究了其性能，并优化了施镀条件。结果表明，以硫酸镍为主盐可在镁合金基底上制得致密、厚度均匀、与基体结合良好的纳米TiO2／Ni—P复合镀层；复合镀层的硬度比无纳米合金镀层显著提高，但纳米颗粒加入量超过2g／L后镀层表面硬度几乎不再随加入量变化；复合镀层和合金镀层的耐腐蚀性都比基底镁合金高得多；纳米复合镀可提高镍磷合金镀层在3．5％NaCl溶液中的耐蚀性，而加入过多的纳米颗粒可以使复合镀层的耐蚀性降低。     

Ni-P/Ag纳米复合化学镀层的耐磨损性能

Ni-P/非金属纳米化学镀溶液中纳米粒子容易团聚,镀液难以保持稳定性.在化学镀Ni-P溶液中添加纳米银粒子,在钢铁基体上制备了Ni-P/Ag纳米复合镀层.用显微硬度计、金相显微镜等技术分析了镀层的厚度、硬度和表面形貌,用磨损试验机研究了镀层的耐磨损性能.结果表明:银纳米粒子在镀液中的含量为1.0×10-7mol/,L,银纳米粒子加快了镀层的沉积速度,使纳米复合镀层厚度增加;在相同的施镀条件下,Ni-P/Ag纳米复合镀层比Ni-P镀层具有更高的硬度和更好的耐磨损性能.     

Ni-P-TiO2纳米复合镀层的制备及性能研究

用化学沉积方法制备了Ni-P-TiO2纳米复合镀层,通过XRD、SEM、TEM和EDS对纳米复合镀层进行了表征,分析了在3.5%NaCl溶液中TiO2纳米颗粒浓度对纳米复合镀层的耐蚀性能影响,研究了热处理温度对复合镀层显微硬度的影响.结果表明:所得复合镀层中纳米粒子的复合量可达到11.33%;在3.5%NaCl溶液中,当TiO2浓度为8g/L时复合镀层腐蚀电位最高,耐蚀性能最好;在镀态或热处理后,复合镀层的硬度都明显高于Ni-P合金镀层,且经过400℃热处理后,复合镀层的硬度高达Hv1160.     

镁合金Ni-Cu-P/纳米TiO2化学复合镀层性能探究

对镁合金表面化学镀Ni-Cu-P进行改进,在其镀液中加入纳米粒子TiO2,在镁合金AZ91D上获得耐磨耐蚀性能优良且兼具有抗菌性能的化学复合镀层.对此镀层表面形貌、组织结构、抗菌、耐磨、耐蚀性能进行了分析,结果表明:该镀层均匀、致密,结合力优良;Ni-Cu-P/纳米TiO2化学复合镀层磨料磨损最佳耐磨性是基材的1.69倍,粘着磨损最佳耐磨性是基材的1.63倍;耐氯化钠和醋酸溶液腐蚀结果均显示该镀层具有较好的耐蚀性;抗菌性能中最佳杀菌率为99.7%,达到了理想的效果.     

AZ91D镁合金Ni-Cu-P/纳米TiO_2化学镀层的抗菌性能

为了探究化学复合镀Ni-P层的抗菌性能,对AZ91D镁合金进行了Ni-Cu-P/纳米TiO2化学复合镀,制备出了具有光催化性能及优异抗菌性能的镀层.利用扫描电镜和x射线衍射技术对镀层进行了分析,并对镀层进行了紫外光照射.结果表明:TiO2粉末与复合镀层使甲基橙的脱色率均为12.5%;镀液中TiO2含量为4 g/L时抗菌性能达99.70%,其余含量时抗菌率均达到95.00%以上.     

纳米金刚石复合镀层制备工艺的研究

纳米金刚石复合镀层具有金刚石和纳米颗粒的双重特性,应用前景广阔.采用复合电镀法制备了Ni-纳米金刚石复合镀层,考察了阴极电流密度、镀液pH值以及搅拌强度对纳米复合镀层显微硬度的影响,并分析了Ni-纳米金刚石复合镀层的共沉积过程.结果表明,选择适当的共沉积工艺参数,可以制备出同底材结合牢固,金刚石微粒弥散较均匀的高硬度纳米复合镀层,基质Ni中金刚石粒子的含量与镀面的机械俘获粒子的能力有关.     

海外文献速递

电　镀2 0 0 2 0 90 1　显微工程中镍与硬纳米粒子复合层的电沉积———ＰｅｔｒｏｖａＭ .Ｇａｌｖａｎｏｔｅｃｈｎｉｋ ,2 0 0 1,92 (5 ) :136 6 (德文 )电镀镍硬纳米粒子复合层使用的镀液为氨基磺酸镍槽 ,第二相包括碳化硅、金刚石、氧化钛、氧化锆。详细介绍了工艺过程 ,ＳＥＭ观察了镀层的表面形貌 ,测定了每种复合镀层的显微硬度 ,其中含金刚石粒子的显微硬度最高。2 0 0 2 0 90 2　纳米金刚石与铬的共沉积———ＭａｎｄｉｃｈＮＶ .ＭｅｔａｌＦｉｎｉｓｈｉｎｇ ,2 0 0 1,99(6 ) :117(英文 )介绍了 3种电镀铬复合层的铬槽 :Ｓａｒ…     

Ni-P-纳米TiO2(溶胶)化学复合镀及镀层防腐蚀性能研究

为了改善Ni-P-纳米TiO2化学复合镀镀层的耐腐蚀性能和沉积速度,采用失重腐蚀法、磁力测厚仪和电化学方法,研究了工艺、配位剂、纳米TiO2溶胶含量对Ni-P-TiO2（溶胶）纳米化学复合镀镀层的沉积速度、腐蚀速率、孔蚀电位的影响,得出其较优工艺配方为：25.0g／L硫酸镍、25．0g/L次磷酸钠、15．0g/L乙酸钠、15．0g／L硼酸,1h,pH值5．5～6．5,80℃,100r／min,12.5mL／L纳米TiO2溶胶。此外,研究显示可用配位剂硼酸代替传统的乳酸。结果表明,在盐腐蚀介质中,Ni-P-纳米TiO2（溶胶）镀层的耐腐蚀性能比Ni-P镀层提高10多倍,在碱性腐蚀介质中提高约1倍,而在酸性介质中耐蚀性比Ni-P镀层略差。     

纳米TiO_2-Ni基镀层的电刷镀沉积行为研究

为了使纳米颗粒均匀地悬浮在镀液中从而获得纳米颗粒均匀分布的复合镀层,研究了不同表面活性剂对纳米TiO2在镀液中的分散行为的影响,采用电刷镀方法制备纳米TiO2-Ni基复合镀层,并运用SEM、EDS和XRD研究了纳米TiO2-Ni基镀层的表面形貌和成分特点。结果表明,阳离子型表面活性剂十六烷基三甲基氯化铵(CTAB)对纳米TiO2颗粒的分散效果最好,沉降时间超过40min;CTAB分散的纳米TiO2-Ni基镀层显微硬度比不加表面活性剂的提高50%左右,镀层结合性较好,孔隙率显著降低;CTAB分散的纳米TiO2-Ni基镀层均匀细致、晶粒细小,纳米TiO2被生长着的镍晶粒夹持嵌埋,分布于镍基间隙中,镀层由纳米TiO2颗粒和镍基组成。纳米粉末与镍共沉积符合迁移、吸附、嵌埋的过程。     

Ni-Co/纳米ZrO_2复合材料的电化学行为及摩擦磨损性能

通过超声辅助电沉积的方法,在加入粒径为50nm的ZrO_2粉体的氨基磺酸盐镀液中制备了Ni-Co/纳米ZrO_2复合镀层。利用电化学方法(线性扫描伏安法、循环伏安法)对沉积动力学进行分析。通过XRD,SEM和EDS分别对复合镀层的微观结构、表面形貌和相组成等进行表征。同时,对镀层进行了纳米压痕测试和旋转摩擦测试。结果表明,Co~(2+)的电沉积行为遵循3D"成核/生长"机制,合金共沉积电位为-0.72V,复合共沉积电位为-0.70V。ZrO_2纳米粒子的加入降低了体系的极化度,使得电极过程更容易进行。纳米ZrO_2的添加量为15g/L时,镀层硬度、弹性模量以及硬模比分别为6.13GPa,291GPa和0.026;摩擦因数为0.3273,磨损量为0.55×10~(-5)g/m,分别为Ni/Co合金的3/4和1/2,超声和纳米粒子的协同作用能够明显改善镀层的力学性能。     

Synthesis and characterization of large-area graphene and graphite films on commercial Cu-Ni alloy foils

Controlling the thickness and uniformity during growth of multilayer graphene is an important goal. Here we report the synthesis of large-area monolayer and multilayer, particularly bilayer, graphene films on Cu-Ni alloy foils by chemical vapor deposition with methane and hydrogen gas as precursors. The dependence of the initial stages of graphene growth rate on the substrate grain orientation was observed for the first time by electron backscattered diffraction and scanning electron microscopy. The thickness and quality of the graphene and graphite films obtained on such Cu-Ni alloy foils could be controlled by varying the deposition temperature and cooling rate and were studied by optical microscopy, scanning electron microscopy, atomic force microscopy, and micro-Raman imaging spectroscopy. The optical and electrical properties of the graphene and graphite films were studied as a function of thickness.     

NdFeB磁性基材化学镀Ni-Cu-P初期形核过程及机赦

为了弄清NdFeB磁性材料表面化学镀Ni-Cu-P合金初期形核过程及机制,研究了不同时间化学镀Ni-Cu-P合金层初期形核过程、形貌和组织结构特征。结果表明：初期沉积过程具有明显的择优倾向和不均匀性：Ni和Cu原子并非以单个原子的形式沉积于基体表面,而是还原后在固．液界面处形成原子团在基体表面高能量区域优先沉积形核,然...     

Low-temperature growth of nanostructured diamond films

Nanostructured diamond films are grown on a titanium alloy substrate using a two-step deposition process. The first step is performed at elevated temperature (820 degrees C) for 30 min using a H2/CH4/N2 gas mixture to grow a thin (approximately 600 nm) nanostructured diamond layer and to improve film adhesion. The remainder of the deposition involves growth at low temperature (< 600 degrees C) in a H2/CH4/O2 gas mixture. The continuation of the smooth nanostructured diamond film growth during low-temperature deposition is confirmed by in situ laser reflectance interferometry, atomic force microscopy, micro-Raman spectroscopy, and surface profilometry. Similar experiments performed without the initial nanostructured diamond layer resulted in poorly adhered films with a more crystalline appearance and a higher surface roughness. This low-temperature deposition of nanostructured diamond films on metals offers advantages in cases where high residual thermal stress leads to delamination at high temperatures.     

The Gas-Phase Synthesis of a New Functional Hybrid Material on the Basis of Multiwalled Carbon Nanotubes Decorated with Faceted Aluminum Nanocrystals

The deposition of polyhedral aluminum nanocrystals onto the surface of multiwalled carbon nanotubes (MWCNTs) via metalorganic chemical vapor deposition with the use of triisobutylaluminum as the precursor has been performed for the first time. The new hybrid nanomaterial (Al/MWCNTs) has been characterized by X-ray phase analysis, scanning electron microscopy, and high-resolution transmission electron microscopy. The obtained Al/MWCNTs hybrid materials were tested as the filler for the creation of threedimensional composites on the basis of an AMg2 alloy via powder metallurgy. It has been shown that the use of Al/MWCNTs as the filler increases the hardness of the composites by 18% in comparison with the initial MWCNTs.     

Effect of Precipitating Phases on Tensile Strength and Microstructural Stability of a Spray-Deposited Al-Si-Fe-Mn-Cu-Mg Alloy

Spray deposition is a novel process which is used to manufacture rapidly solidified bulk and near-net-shape preforms. In this study, AI-20Si-5Fe-3Mn-3Cu-1Mg alloy was synthesized by spray deposition technique. The aging process of the alloy was investigated by differential scanning calorimetry (DSC) analysis and transmission electron microscopy (TEM). The results show that two kinds of phases, i.e. S(Al2CuMg) and σ(Al5Cu6Mg2), precipitate from matrix and improve the tensile strength of the alloy efficiently at both the ambient and elevated temperatures (300℃). In addition, the σ-Al5Cu6Mg2 is a relatively stable phase which improves microstructural stability of the alloy.     

冷喷涂中颗粒形状和温度对其沉积过程的影响

为提高镁合金的抗腐蚀性能,以冷喷涂方法在其表面喷涂铝颗粒并采用有限元ALE网格方法对该过程进行了数值计算。考察了颗粒和基板的变形特性、温度分布;研究了颗粒形状、颗粒和基板初始温度对其沉积过程、颗粒反弹特性等的影响。结果表明,颗粒形状对系统局部变形影响较大;颗粒形状及速度对其反弹能、基板表面坑深、最大接触面积等也有较大影响。对系统预热有利于颗粒和基板的结合。当椭球形颗粒沿着其长轴碰撞以及球形颗粒碰撞时,温度和塑性变形都对称分布。结果可初步用于冷喷涂实验参数的选择和优化。     

Effect of lactic acid on nucleation morphology and surface roughness of electroless Ni–P deposition in nanoscale

The present work aims to study effect of lactic acid concentration as complexing agent on surface roughness and nucleation morphology of electroless N?CP deposition. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) have been used to study nucleation morphology and surface roughness of deposition. Deposition process started at some initial priority growing centres independently distributed on the substrate. We found that the morphology and surface roughness of deposition strongly depends on the complexing agent concentration. Morphology of initial deposited centres with no concentration of lactic acid was in coniform structure. By increasing the complexing agent concentration, the structure of initial growing centres changed from coniform to nodular shape and the surface roughness of depositions decreased.     

Preparation of New Type Ni-P Micro/Nano Metal Material Based on Bacteria Shape

A new type of Ni-P alloy with rod-shape was prepared by electroless deposition method based on the shape of Nocadia, a kind of bacteria. The material was characterized by microbiological method, scanning elec-tron microscope, energy dispersion spectroscopy, transmission electron microscopy, fourier transform infrared spectroscopy, X-ray diffraction and vibrant sample magnetometer. It was found that Ni-P alloy deposited on Nocadia surface was amorphous when pH=8.0. The amount of Ni crystalline increased with pH of plating solution. Ni-P nano-particles deposited on active locations on the surface at the initial stage, and then ho-mogeneous Ni-P film formed with time. Nocadia remained their original rod shape after Ni-P nano-particles deposition. The new type metal material formed of Ni-P alloy with nano-particles was prepared. The mag-netization of the material prepared at pH=9.7 is greater than that prepared at pH=8.0. The magnetic loss of the material prepared at pH=9.7 is less than 0.1. The dielectric loss exceeds 0.3 when frequency is higher than 14 GHz, which is 1.5 at 18 GHz. The new type Ni-P metal material with Nocadia shape has dielectric loss property.     

Microstructural characterization and dry sliding wear resistance of MoO2-strengthened γ/NiMo alloys with different primary phases

Two γ/NiMo alloys strengthened by a refractory metal oxide MoO₂ phase were fabricated by a laser melting deposition process. Microstructural transformation of the alloys with different primary phases was identified and the crystal structure of the primary phases was confirmed by both X-ray diffraction and transmission electron microscopy. Meanwhile, room-temperature dry sliding wear behavior and mechanism difference of the alloys were also investigated mainly by scanning electron microscopy. Microstructures of the alloys varied from hypoeutectic to hypereutectic, as the molybdenum content increases. The hypoeutectic alloy was solidified on the basis of a Ni-base solid solution γ primary phase, whereas the hypereutectic alloy was grown based on an intermetallic compound with NiMo primary phase. The γ, NiMo primary phases and MoO₂ strengthening phase were confirmed to have face-centered cubic, orthorhombic and monoclinic structures, respectively. Compared with the hypoeutectic alloy, the hypereutectic alloy exhibited higher wear resistance under the same condition. The predominant wear mechanism of the γ/NiMo alloys transformed from micro-cutting to microcracking.     

AZ91D镁合金锌系磷化膜成膜机理和生长过程的研究

以磷酸盐化学转化膜为研究体系,采用SEM、XRD、OCP等分析方法及检测手段,研究AZ91D镁合金系磷酸盐化学转化膜的成膜机理、膜层结构及生长过程。研究发现AZ91D镁合金在磷化液中成膜过程分5个阶段:初始成核(1～5s)、基体快速溶解(5～60s)、晶体快速生长(1～2min)、膜层稳态生长(2～10min)和膜层沉积溶解平衡阶段(10min以后)。AZ91D镁合金表面的磷酸盐晶核的形成并非在金属进入溶液的最初时刻一次形成,是分批形成。最先形成的晶核逐渐长大,新的晶核不断生成,磷酸盐晶粒对其表面的覆盖度逐渐增大,直至各个晶粒逐渐长大相互接界,将其表面完全覆盖,结晶过程结束。晶核的形成未优先发生在基体金属的晶界上,随着晶核的生长和外延而形成磷化膜。