The Properties of Bright Nickel Electrodeposits in Relation to the Period of Service of the Plating Bath

Atmospheric exposure tests at industrial and marine sites and accelerated tests in a moist atmosphere containing sulphur dioxide showed no tendency for the corrosion resistance of organic bright nickel + chromium coatings to vary with increasing length of service of the nickel bath. The pattern of attack was very similar in atmospheric and accelerated tests. Crazing of the chromium occurred to about the same extent in an industrial atmosphere as in the sulphur dioxide test. Extended salt spray tests had almost no effect on the coatings.     

The Structure and Protective Properties of Zinc and Nickel Alternate Electrodeposits

A NEW TYPE of coatings consisting of a large numberof laminar deposits has been the keen subject of muchresearch,because these layered-structure coatingspossess improved properties or novel phenomenon suchas increased mechanical strength,micro-hardness,giantmagnetoresistance and corrosion resistance[1"6'.Thesecoating systems with individual layers making upoverall structure are also called compositionallymodulated multilayer(CMM)coatings'3"5'.In view ofthe plating historical use of surface…     

用磁力搅拌法对Ti(C,N)粉体表面化学镀镍(英文)

研究在不使用感光剂和催化剂的条件下,对Ti(C,N)粉体表面进行化学镀镍,并利用XRD,SEM和EDS方法对镀镍后的Ti(C,N)粉体进行表面评价。结果显示:通过磁力搅拌法得到的Ti(C,N)粉体表面存在明显Ni-P镀层,而通过机械搅拌得到的Ti(C,N)粉体表面没有明显镀层出现,磁力搅拌过程中产生的磁场可能是Ni-P镀层产生的。     

The Properties of Bright Nickel Electrodeposits in Relation to the Period of Service of the Plating Bath. III-Composition and Microstructure

Carbon, oxygen, Hydrogen and nitrogen contents of bright nickel deposits from two proprietary solutions were determined by chemical analysis. The amount of organic material incorporated in the deposits tended to increase with increasing length of service of the plating bath. For both types of bright nickel there seemed to be a definite relationship between the ductility of the deposits and the amount of material (addition agents and impurities) included in them.

The results indicate that additions of anti-stress agent made periodically to one of the solutions, which tended to lower stress and raise ductility, reduced the total amount of organic material in the deposit. This requires confirmation, but could have important practical and theoretical implications.     

结晶器参数对电磁搅拌磁流耦合特性的影响研究

基于ANSYS有限元数值模拟方法研究了电磁搅拌中结晶器对磁流耦合场的影响规律。结果表明,结晶器的存在导致金属熔体中的磁场、电磁力以及流速等参数均减小;随着结晶器厚度的增加,金属熔体中的最大磁场和流速下降较快。     

Ce（SO4）2对化学镀镍液及镀层性能的影响

采用电化学方法研究了Ce（SO4）2对化学镀镍液及镀层性能的影响。结果表明：Ce（SO4）2的添加总体上提高了化学镀镍层的耐腐蚀性能和沉积速率,当加入量为2mg·L^-1时,镀层具有最高的沉积速率;当加入量为5mg·L-1时,镀层具有最好的耐蚀性能;Ce（SO4）2能够在电极表面吸附,对次亚磷酸根氧化的促进作用表现在提高了其氧化电流密度,并通过影响化学镀镍的阳极反应来影响化学镀镍层的沉积速率;Ce（SO4）2的加入增大了化学镀镍反应的活化能,提高镀液的稳定性。     

氧化铝粉末表面的快速镍金属化及其磁学性质

基于溶液/氧化铝界面的自催化氧化-还原反应,实现了金属镍在氧化铝粉末表面上的快速化学沉积,制备了氧化铝颗粒表面包覆镍层的微粉产物。用X射线衍射(XRD)、扫描电子显微镜(SEM)、剖面金相显微分析和傅立叶变换红外光谱(FTIR)综合表征了产物的形貌及结构。镍金属壳层由纳米级大小的晶体镍颗粒组成,厚度为2μm左右。镍包氧化铝产物具有类似于金属镍的导电性和磁学特性,其压片电阻率近似为零;饱和磁化强度(Ms)为39.6A·m2·kg-1,剩余磁化强度(Mr)6.0A·m2·kg-1,矫顽力(Hc)为6336A/m。     

镀液pH值对Co-Pt-W薄膜磁性能的影响(英文)

研究了溶液pH值对电沉积Co-Pt-W磁性能的影响。通过VSM,SEM及XRD技术分析研究了薄膜的磁性能和微结构。M-T磁化曲线表明,在不同pH值的溶液中所制备的磁性薄膜呈现出不同的热磁行为。在高pH值(pH=8.5)的情况下,所制备的薄膜随着温度升高,磁矩在降低;相反,在pH值为5.0的条件下,其磁矩则随着温度的升高先减小后增加,磁矩的降低对应于晶相的居里温度。VSM的测试表明,薄膜的矫顽力在很大程度上与溶液的pH值相关。同时,根据XRD的测试可知,磁性能的变化同样伴随着薄膜中相的转变。     

磁力研磨工艺对整体叶盘表面完整性的影响

针对铣削加工对整体叶盘零件表面完整性控制不能满足使用要求的难题,利用磁力研磨所特有的柔性、自适应性、可控性等优点,研发了一种基于机器人的自由曲面磁力研磨装置,对整体叶盘零件进行加工试验。试验结果表明:经过磁力研磨后零件的表面粗糙度数值大幅度降低;铣削加工残留下来的加工纹理基本去除;原始表面上的微裂纹减弱或彻底消除;近表层原始显微组织中的变质层被部分去除;残余应力也明显减小。由此表明磁力研磨加工工艺能够提高整体叶盘的表面完整性,从而可以提高零件的疲劳强度和使用寿命。     

电磁搅拌工艺对AZ91D合金组织和性能的影响

研究电磁搅拌频率、合金冷却速率对AZ91D合金组织及性能的影响.试验结果表明,冷却速率为2.0℃/s时,电磁搅拌频率大于20 Hz的电磁搅拌工艺可制备出初生α-Mg相尺寸小于80 um、形状因子大于0.8的AZ91D合金;电磁搅拌频率大于20 Hz时,电磁搅拌频率对初生α-Mg相尺寸影响甚微,但形状因子随频率的增加而增大.在冷却速率大与搅拌频率高的条件下,电磁搅拌工艺制备AZ91D合金的力学性能和耐腐蚀性能均有所提高.     

Influence of Ultrasound on the Properties of Electroless Plated Nickel

Ultrasonic agitation during electroless plating nickel affects the structure and properties of the deposits. In this work, a complete study was made of the action of ultrasound on the plating rate, micro-hardness, phosphorus content and corrosion properties of electroless plated deposits. It was found that in the presence of the ultrasound, the plating rate and micro-hardness of as-deposited were increased by about 30 and 10 percent respectively, whilst the phosphorus content was decreased from 10.49 to 8.39 at%. The changes in these parameters, in turn, affect the corrosion behaviour of the electroless deposits. The deposit formed with ultrasound exhibited active corrosion characteristics, whilst the deposit formed without ultrasound had a passive behaviour in 0.2 M H²SO⁴ solution.     

Effect of Substrate Type and Temperature on the Tribological Properties of MoS_x Coatings

SPUTTERING deposited MoSx coatings are often usedas a solid lubricant in space applications,where a lowcoefficient of friction and long lifetime of coating areneeded.But the lubricating properties and endurancelives of sputtered MoSx coatings are strongly dependenton the sputtering parameters and the substrateconditions.Spalvin[1]showed that three groups can be dividedabout the effect of temperature on the nucleation ofMoSx coatings:(1)amorphous(-195°C);(2)crystalline-amorphous(-195°C …     

Effect of the Current Density on Morphology,Porosity, and Tribological Properties of Electrodeposited Nickel on Copper

In the steel industry, nickel coating on copper has increased the lifespan of continuous ingot casting molds. The objective of this work is to estimate the porosity of nanocrystalline nickel electrodeposited onto copper. Characteristics of nickel coating such as hardness, wear resistance, porosity, morphology, and adhesion are very important for maximum performance of molds. The effective porosity in nickel coating was determined by using anodic voltammetry. The porosity of electrodeposited nickel onto copper increased from 0.16% up to 6.22% as the current density increased from 1.5 up to 8.0 A dm⁻². The morphology of the nickel electrodeposited at lower current densities was more compact. Tribological properties were studied using hardness measurements, and calotest. Results of calotest indicated a wear coefficient of 10⁻⁶ for all samples. An extremely low friction coefficient of 0.06-0.08 was obtained for the sample deposited with a current density of 1.5 A dm⁻², and a friction coefficient of 0.15-0.21 was measured for the nickel coating electrodeposited at a current density of 5 A dm⁻². Effects of the current density of the electrodeposition process on the morphology, porosity, and tribological properties were evaluated.     

The Influence of Adsorption Processes on Structural and Catalytic Properties of Nickel

Protection of Metals and Physical Chemistry of Surfaces - The effect of the conditions for carrying out the reaction of liquid-phase hydrogenation of the nitro group on a bulk nickel catalyst in a...     

旋转磁场对激光熔凝钛合金熔池的影响研究

本文运用有限元方法对不同频率下电磁搅拌辅助装置中心处磁场强度以及熔池电磁力进行了模拟分析,并研究了旋转磁场对熔池电磁力和熔池温度分布及流场影响,结果表明当电流频率增大时,熔池中电磁力首先有缓慢减小趋势,同时功率损耗迅速增大,当频率继续增大时,电磁力逐渐增大,此时功率损耗基本趋于稳定;在激励电流变化的一个周期内,搅拌装置中磁场强度也发生周期性变化。在施加旋转磁场条件下,熔池整体温度有所降低,温度梯度减小,熔池内形成围绕熔池做周向流动的环流,流速分布均匀。     

氧化石墨烯对锂基润滑脂摩擦学性能的影响

目的 研究氧化石墨烯(GO)作为添加剂对润滑脂摩擦性能的影响.方法 将鳞片石墨利用经典的Hummers氧化法氧化得到GO,并表征了GO,再分别以不同的质量分数(0.1％、0.3％、0.5％、1.0％、1.5％)与润滑脂复配.同时增加了空白润滑脂与石墨粉复配的润滑脂作为对比.利用Optimol SRV型摩擦磨损试验机评价...     

搅拌摩擦加工MB8镁合金的组织与力学性能分析

研究了MB8(Mg-1.5Mn-0.3Ce)合金在FSP不同工艺参数条件下的组织和力学性能。试验在加工速度恒定为60mm/min,旋转速度分别为800、1200和1800r/min的条件下进行。结果表明,经FSP加工,原始轧制态MB8镁合金的粗大不均匀组织受到搅拌头的剧烈搅拌作用而破碎、分散,并发生动态再结晶,获得细小、均匀的等轴晶粒。在转速为800r/min时,搅拌区的平均晶粒尺寸由原始轧制态的16.5μm细化至6μm。常温拉伸试验结果表明,MB8镁合金经FSP加工后抗拉强度大幅下降,但伸长率显著增大,在1200r/min时伸长率达57%,是原始材料伸长率的160%。此外,采用SEM观察拉伸试样断口,分析了MB8镁合金的断裂机制。     

电磁搅拌参数对Cu-6%Ag合金凝固组织及性能的影响

为了细化Cu-Ag合金,进一步提高合金性能,在不同电磁搅拌参数下制备了Cu-6%Ag合金。结果表明,随着电磁搅拌频率和电流增加,合金晶粒明显细化。初生Cu枝晶转变成等轴晶和胞晶,并且胞晶中的Ag元素含量降低明显。枝晶状初生Cu相有利于合金硬度升高,等轴晶状Cu相有利于提高合金的电导率。     

The Effect of Brush Plating on the Structure and Wear Properties of Electrodeposits

In this work, the structure and wear properties of brush plated electrodeposits were investigated. An additive free sulphamate solution was used for plating with different methods of solution supply as well as conventional bath plating, and the structures were investigated by TEM and X-ray diffraction.

The structure of the nickel sulphamate deposit obtained by brush plating with pumped solution supply was found to resemble that of bath plated deposits. When solution supply was realised by dipping of the anode, the coatings had a more fine grained structure and higher hardness.

Ball-on-ring tests were carried out on samples brush plated with different nickel and cobalt alloy coatings. A comparison was made with specimens bath plated with hard chromium. The cobalt and chromium deposits gave similar results, while nickel coatings were found to be less wear resistant.     

Cu颗粒和条纹表面织构的协同作用对摩擦副摩擦磨损性能的影响

利用电加工的方法在45钢表面制备了宽度为15μm,深度为30 μm的条纹织构,在SRV往复式摩擦磨损试验机上对具有不同织构面积率的试样进行了摩擦磨损性能试验,分别考察了在纯液体石蜡和添加Cu颗粒液体石蜡润滑条件下摩擦副的摩擦因数和磨损情况,并结合扫描电镜观察和能谱分析研究了表面织构与Cu颗粒协同作用对摩擦磨损行为的影响.结果表明:在摩擦过程中,Cu颗粒能够改善摩擦磨损性能,而条纹织构的存在一方面增大了摩擦,但同时也起到了容纳磨屑的作用.条纹织构对摩擦因数的影响和织构面积率以及施加的载荷有关.在较大载荷下,二者的协同作用能有效的降低摩擦因数.在实验初期,添加0.2%Cu颗粒液体石蜡润滑条件下,当载荷为300 N时,织构面积率为15%的表面平均摩擦因数比原始表面降低约13.5%;而当载荷为500 N时,织构面积率为30%的表面的平均摩擦因数比原始表面降低约11.8%.