电沉积非晶态Co-W合金镀层在碱性溶液中的电催化析氢研究

利用恒电流直流电沉积方法在Cu基底表面制备了Co-W合金镀层,当镀液中WO_4~(2-)浓度≥0.075 mol/L时镀层为非晶态结构。电化学研究表明,非晶态Co-W合金镀层在1 mol/L NaOH溶液中表现出良好的电催化析氢活性,过程受Volmer-Heyrovsky路径控制。W含量约为40.1%(质量分数)的Co-W合金镀层析氢活性最强,其表观交换电流密度j_0为3.17×10~(-5)A/cm~2;当电位负于-1.464 V(相对于饱和甘汞电极电位)后该Co-W合金镀层的阴极电流密度超越了商用Pt片。结合电化学阻抗分析获知,由于镀层本征催化活性和比表面积(或电化学活性面积)均得到提升,使得非晶态Co-W合金镀层析氢活性获得提高。     

玻璃基体上电沉积Li—Co合金镀层的性能研究

对玻璃基体上电沉积Li-Co合金镀层的工艺及镀层的性能进行了研究，对底镀层的形貌、成分、结构进行了观察和分析，并测定了镀层的耐腐蚀性。结果表明，镀层在0．5mol/L H2SO4和5％ NaCl（pH=3）中的耐蚀性与1Cr18Ni9Ti相当。     

不同铁含量的碱性Zn-Fe合金镀层在3种溶液中的耐蚀性能

含铁量低于1%(质量分数,下同)的Zn-Fe合金具有优异的耐腐蚀性能,有必要对其耐蚀性及机理做深入研究。采用动电位极化技术和交流阻抗方法(EIS)研究了未钝化的纯Zn镀层和碱性Zn-Fe合金镀层(含铁0.15%～0.89%)在0.2 mol/L Na2B4O7-H3BO3,含0.05 mol/L Cl-的0.2 mol/L Na2B4O7-H3BO3和1%NaCl溶液中的耐蚀性能,采用XRD法研究了不同镀层的晶体结构。结果表明:少量铁在锌中的存在明显影响锌的耐蚀性能,含铁0.15%～0.60%的Zn-Fe合金镀层腐蚀电阻和反应电阻都较纯Zn层的大,腐蚀电流密度较小,在一定电位范围内形成的电化学钝化膜耐Cl-点蚀的能力强;含铁量为0.29%的合金表现出了最好的耐蚀性;Zn-Fe合金镀层与碱性纯Zn镀层的晶体结构相同,都是六方密排结构,铁在Zn-Fe合金中不是以独立相而是以固溶相的形式存在。     

碱性锌酸盐体系锌钴合金电镀工艺研究

目前国内对碱性锌酸盐体系电镀锌钴合金的研究较少。研究了碱性锌酸盐Zn-Co合金电镀体系中合金镀液组成及工艺条件对镀层Co含量的影响,得到了最佳镀液组成及工艺条件:锌钴离子总浓度0.3 mol/L,锌钴离子摩尔比9∶1,150 g/L氢氧化钠,15.0 m L/L添加剂A,1.0 m L/L添加剂B,电流密度Jc3 A/dm2,温度25~30℃。在最佳工艺条件下可得到Co含量为2.0%~2.2%的Zn-Co合金镀层。结果表明:Zn-Co金的沉积表现为异常共沉积;在一定范围内,镀层中钴含量的变化会影响镀层光亮度的变化;钴配位剂对Zn-Co合金的共沉积电化学行为不造成影响。     

Ni-Mo-P非晶态合金电沉积工艺及镀层耐蚀性

通过正交试验优化镀液组成和工艺参数,用电沉积法获得了外观呈银白色、平整光滑的Ni-Mo-P非晶态合金镀层。用扫描电镜、X射线衍射、能谱分析及电化学极化曲线法研究了镀层的表面形貌、组织结构、化学组成及耐蚀性能。结果表明,由于钼元素的加入,镀层的组织结构得到改善,致密性增加,在5%NaCl和0.5mol/L H2SO4溶液中的耐蚀性较不锈钢和Ni-P非晶镀层的更为优异。     

钒对Zn-Fe合金镀层耐蚀性的影响

在电镀液中加入钒盐,在A3钢表面电镀出Zn-Fe合金薄膜.采用稳态法和循环伏安法研究了Zn-Fe合金镀层在30℃下0.5 mol/L H2SO4溶液中的腐蚀行为,采用扫描电镜(SEM)和X射线衍射(XRD)分析了钒对镀层在腐蚀前后微观结构的影响,用交流阻抗法研究了钒对电极等效电路的影响.结果表明,加入钒盐能改变Zn-Fe合金镀层的晶面择优取向和织构系数,当钒盐加入量为0.50～0.75 g/L时,镀层变得均匀、致密,镀层的致钝电流密度Jpp和维钝电流密度Jp明显降低,极化电阻增大,在强酸性溶液中的耐蚀性能明显增强.     

玻璃基体上电沉积Ni-Co合金镀层的性能研究

对玻璃基体上电沉积Ni Co合金镀层的工艺及镀层的性能进行了研究 ,对底镀层的形貌、成分、结构进行了观察和分析 ,并测定了镀层的耐腐蚀性。结果表明 ,镀层在 0 .5mol/LH2 SO4 和 5%NaCl(pH =3 )中的耐蚀性与 1Cr18Ni9Ti相当     

化学沉积Ni-Zn-P合金及其冲蚀特性

研究了镀液中硫酸锌、次亚磷酸钠、pH值及镀液温度对化学沉积Ni-Zn-P合金沉积速度、镀层成分和镀层表面形貌的影响。用SEM、EDS和XRD对沉积层进行表征。确定最佳工艺条件为:硫酸镍25g/L,次亚磷酸钠30g/L,硫酸锌8g/L,柠檬酸钠60g/L,硫酸铵25g/L,乳酸30ml/L,镀液温度为(85±1)℃,镀液pH值为9.0。X射线衍射分析表明,镀态下化学沉积Ni-Zn-P合金由非晶态的相和镍的固溶体存在。研究了沉积层在0.05mol/L盐酸流动介质中的冲蚀行为,化学沉积Ni-Zn-P合金层质量损失随介质流动速度提高,冲击角度的减小而增加。     

Sn40Pb共晶合金电镀工艺

目的对Sn40Pb共晶合金电镀工艺过程进行研究。方法采用电镀和超声辅助搅拌,Sn40Pb作为电镀阳极,在铜片上成功的制备了Sn40Pb共晶合金镀层。结果研究表明随着电流密度增大,镀层厚度增加,镀层中铅含量增加较快,电流密度过大时阴极析氢反应剧烈,锡铅镀层会变得粗糙,致密性变差。结论当电镀液成分为甲基磺酸为12 m L(24 g/L)、甲基磺酸锡为8 m L(16 g/L)、甲基磺酸铅为3.7 m L时,控制电流密度在4 A/dm~2、电镀时间为5 min左右,可以获得接近锡铅共晶的理想合金镀层。     

沉积电流密度对不锈钢表面Pd-Co合金镀层耐沸腾含Br~-甲乙混合酸腐蚀性能的影响

目前,鲜见Pd-Co合金镀层耐高温非氧化性腐蚀的研究报道。在不锈钢表面电镀了Pd-Co合金层;利用扫描电镜(SEM)、X射线衍射分析(XRD)、硬度测试、腐蚀失重及极化曲线等手段研究了电流密度对Pd-Co合金镀层耐沸腾含0.005 mol/L Br-甲乙混合酸腐蚀性能的影响。结果表明:随着沉积电流密度的增大,Pd-Co合金镀层中Co含量逐渐增多,膜层晶粒大小逐渐降低,硬度先增大后减小;当电流密度较低时,Pd-Co合金镀层具有较低的孔隙率,在沸腾含Br-甲乙混合酸溶液中具有良好的耐蚀性;当电流密度过高时,Pd-Co合金镀层变得疏松,粗糙度增大,孔隙率增多,耐蚀性显著降低;Pd-Co合金层与Pd镀层相比在搅拌条件下的耐腐蚀性能更好。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.