PVC薄膜电镀Cu-Ni-Cr

进行了PVC薄膜的Cu-Ni-Cr复合镀工艺研究,除物理粗化和化学粗化前处理工序外,后续的脱脂—调整剂处理—钯活化—解胶—化学镀镍—预镀铜—镀酸铜—镀半光镍—镀光镍—镀光亮铬工序均在塑料镀自动加工线上进行.使用金相显微镜、X射线荧光测厚仪(XRF)、精密鼓风干燥箱和扫描电镜(SEM)对复合镀层的厚度、耐热性和表面形貌进行了分析.结果 表明,物理粗化方式处理后获得的复合镀层在光亮度、附着力、热冲击性3方面均优于化学粗化方式获得的复合镀层.物理粗化获得的Cu镀层厚度均匀性较差,而Ni镀层厚度均匀性与化学粗化的比较接近,这是由于酸铜镀液分散能力好,填平能力强,从而使两种粗化获得的铜镀层表面都是平整的,但物理粗化的表面粗糙度较大,所以镀铜层厚度均匀性差.而镀镍是以镀铜层为基底,由于镀铜层的表面都很平整,所以两种前处理获得的镍层厚度相差不大.     

Ag/Cu和Cu/Ni纳米金属多层膜强度软化的理论分析

用电沉积法分别制备了具有不同调制波长的Ag/Cu和Cu/Ni金属多层膜,研究了多层膜的硬度与调制波长之间的关系.结果表明,当调制波长λ>300 nm时,两种多层膜的硬度与调制波长符合位错塞积机制的Hall-Fetch关系,当λ<300 nm时,都偏离了Hall-Fetch关系;Ag/Cu和Cu/Ni多层膜分别在λ=50nm和100nm处取得硬度峰值.基于Cheng等人的电子理论分别求出了Ag,Cu和Ni金属晶体的位错稳定的临界晶粒尺寸,进而定量地解释了Ag/Cu和Cu/Ni金属多层膜硬度峰值位置.     

1Cr17Ni2压气机叶片多层膜制备及耐蚀性研究

采用真空电弧离子镀技术在1Cr17Ni2不锈钢基体表面沉积Ti/TiN/Zr/ZrN多层膜,并对膜的形貌、相结构、结合力以及极化曲线和交流阻抗等电化学性能进行分析和测试。结果表明:制备的Ti/TiN/Zr/ZrN膜界面清晰、结构致密、晶粒细小,膜层厚度约为2~3μm,膜层的主要物相为TiN和ZrN两相,以及少量的金属Ti和Zr;膜层与基体结合良好,结合力大于70 N,显微硬度(HV_(0.025))高达29 000 MPa,Ti/TiN/Zr/ZrN多层膜与1Cr17Ni2基材相比,具有更高的极化电位和极化电阻,更低的腐蚀电流密度,更大容抗弧。     

The corrosion protection of mild steel by polypyrrole/polyphenol multilayer coating

Electrochemical synthesis of very thin polyphenol (PPhe) film was achieved on polypyrrole coated mild steel electrode (MS/PPy) and a multilayer coating was obtained, cyclic voltammetry technique was used for the synthesis. The corrosion performance of this multilayer coating and single PPy coating were investigated in 0.05 M H₂SO₄ solution by using electrochemical impedance spectroscopy (EIS), anodic polarization curves and open circuit potential (E_ocp)-time curves were used. It was found that the multilayer coating could provide much better protection than the single PPy coating for corrosion of MS for much longer periods and an efficiency of 98.3% was determined for this coating after 340 h exposure time in corrosive medium. It is proposed that the very thin PPhe film coated on top of PPy coating lowered the porosity and improved the barrier effect of the coating significantly.     

Microstructure and corrosion resistance of Cr/Cr2N multilayer film deposited on the surface of depleted uranium

Depleted uranium is widely used in national defence and nuclear energy fields. However, the inferior corrosion resistance limits its application. A Cr/Cr₂N film was prepared by magnetron sputtering on the uranium to improve its corrosion resistance. The Cr/Cr₂N film exhibits modulation structure. The introduction of the Cr/Cr₂N increases the corrosion potential; the corresponding current density decreases about three orders of magnitude. After polarization corrosion, the surface morphology of the Cr/Cr₂N-coated on uranium keeps integrated. Only a thin layer of film (∼40 nm) is oxidized. The Cr/Cr₂N film shows great potential in improving oxidation and corrosion resistance of depleted uranium.     

Nanofabricated multilayer coatings of Zn-Ni alloy for better corrosion protection

As an effort to increase the corrosion resistance of conventional monolayer Zn-Ni alloy coating, the multilayer Zn-Ni alloy coating have been done electrolytically on mild steel (MS), using gelatin and glycerol as additives. Multilayered, or more correctly composition modulated multilayer alloy (CMMA) coatings have been developed using square current pulse. Successive layers of alloys, in nanometric scale having alternately changing composition were fabricated by making the cathode current to cycle between two values, called cyclic cathode current densities (CCCD’s). The coatings having different configuration, in terms of composition and thicknesses of individual layers were developed and their corrosion performances were evaluated by electrochemical methods. The corrosion rate (CR)’s were found to decrease drastically with progressive increase in number of layers (up to 300 layers), and then increased. The coating configurations have been optimized for best protection against corrosion. The CMMA Zn-Ni coating having 300 layers was found to be about 37 times more corrosion resistant than corresponding monolayer alloy, developed from same bath for same time. High protection efficacy of the coatings were attributed to alternate layers of alloys having different surface structure and composition, supported by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) study, respectively. Optimization procedure has been explained, and results are discussed.     

Ni含量对0Cr17Ni4Cu4Nb不锈钢力学性能的影响

研究了Ni含量对0Cr17Ni4Cu4Nb不锈钢力学性能的影响.结果表明:添加Ni元素可以降低合金中的δ-铁素体含量,Ni含量越高,合金中δ-铁素体越少;Ni含量高的合金中的富铜相颗粒分布密集,细小,而Ni含量低的合金中的富铜相分布稀疏,且相对粗大;在相同回火温度下,较高Ni含量的合金的强度较高,塑性较低.     

Cu和Cr对耐候钢的力学性能及耐蚀性能的影响

研究了不同Cu和Cr含量对低合金高强耐候钢的力学性能及耐腐蚀性能的影响规律。结果表明,Cu元素含量对合金的强度影响较为明显,随Cu含量增加,合金的屈服强度逐渐提高;随Cr含量增加,合金屈服强度也略有上升,但强化效果不明显。Cu和Cr的加入均会提高合金的韧脆转变温度,但冲击功的绝对值仍保持在较高的水平。Cu和Cr元素的加入,增加了锈层的致密度,使得合金的耐腐蚀性能得到明显提升。     

Mechanical and corrosion properties of dc magnetron sputtered Al/Cr multilayers

Mechanical and corrosion properties of Al/Cr multilayer coatings deposited by dc magnetron sputtering are investigated and compared to pure Al and Cr coatings. The objective of this study is to increase the mechanical properties of sacrificial Al-based coatings. The results indicate that mechanical and corrosion properties depend on the architecture organisation. The reduction of the layer thickness allows an increase of the coating hardness. The nanolayer architecture leads to a “hard and tough” material compared to the other architectures. Moreover, the intrinsic corrosion resistance is enhanced, as the corrosion and the pitting corrosion potentials are progressively shifted towards positive values. The nanolayer coating presents the highest intrinsic corrosion resistance but multilayer and nanolayer Al/Cr coatings become nobler than the steel substrate. The corrosion resistance of the coated steel is then strongly dependent on the microscopic coating defects which act as preferential pathways for the corrosive solution. So the nanolayer architecture organisation improves the mechanical properties but does not permit to conserve the sacrificial behaviour of the aluminium based coating, which is harmful for the corrosion protection of coated steel.     

Tribological behaviour and residual stress of electrodeposited Ni/Cu multilayer films on stainless steel substrate

In the present study, [Ni (4.5 nm)/Cu (t_Cu = 2, 4 and 8 nm)] multilayers were pulse electrodeposited on stainless steel (AISI SS 304) substrate from sulphate based single bath technique. X-ray diffraction (XRD) was used to investigate the structure and stress of the Ni/Cu multilayer. The results from XRD analysis indicated that the deposited multilayers had a preferred crystal orientation of [111] and presence of satellite reflection suggested the formation of superlattice. The stress level within the deposited multilayers was found to be sensitive to the sublayer thickness. Sliding wear behaviour of electrodeposited Ni/Cu multilayer films has been investigated against a tungsten carbide (WC) ball as the counter body and compared with that of the constituents, Cu and Ni coatings. The wear tests were carried out by using a reciprocating ball-on-flat geometry at translation frequencies of 5 and 10 Hz, slip amplitude of 1 mm and at five different loads of 3, 5, 7, 9 and 11 N. Friction force was recorded on-line during the tests. At the end of the tests, the wear scars were examined by laser surface profilometry and scanning electron microscopy (SEM). Friction coefficient was found to be dependent on load and Cu layer thickness (t_Cu) and the values for multilayers were border between Ni and Cu. Among multilayers, sample with minimum t_Cu has shown the lowest friction coefficient and wear rate. With increasing t_Cu, the wear mechanism changes from pure abrasive wear at t_Cu = 2 nm, to particle entrapment at t_Cu = 4 nm to particle embedding at t_Cu = 8 nm. Detailed investigation of the wear scar morphology as well as wear rate measurement revealed that at low loads, (H/E) ratio and residual stress governed the wear rate and the principle wear mode was abrasive cutting. At intermediate loads, the role of residual stress became insignificant while wear was governed by (H/E) ratio and plastic deformation. However, at higher loads, plastic deformation played the major role.     

Microstructure,mechanical and corrosion properties of TiN/Ni nanomultilayered films

Nanomultilayered TiN/Ni thin films with different bilayer periods(57.8-99.7 nm) and Ni single-layer thickness(3.9-19.2 nm) were prepared by alternatively sputtering Ti and Ni targets in N_2 gas atmosphere.The micros tructure,mechanical and corrosion properties of the multilayer films were investigated by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),X-ray photoelectron spectroscopy(XPS),nanoindenter and electrochemical technologies.The multilayer films are fine with a mean grain size of ～8-9 nm independent of the bilayer period.However,the smoothness and compactness seem to decrease with the bilayer period increasing.The hardness(H) and elastic modulus(E) of the multilayer films gradually decrease as the bilayer period increases,and the multilayer film with bilayer period of 57.8 nm exhibits higher H,ratios of(H/E~*and H~3/E~(*2))(E*is effective Young's modulus)than the monolithic TiN film and the other multilayers.The multilayer films exhibit an obvious passivation phenomenon in 10% H_2SO_4 solution,and the passive current and corrosion current densities decrease,whereas the corrosion potential increases when the bilayer period or Ni single-layer thickness decreases.It is found that the passivating behavior and corrosion potential of the multilayers are more sensitive to Ni single-layer thickness than the bilayer period.More corrosion pits and lamellar flaking could be found on the films with larger bilayer period or Ni single-layer thickness.     

YL12/Cu/0Cr18Ni9Ti异种材料扩散连接接头微观分析

选取纯铜箔作过渡层,采用真空热压扩散工艺,在加热温度480～500 ℃、压力10 MPa、真空度1.0×10-2Pa工艺条件下,制备了变形铝合金LY12和不锈钢0Cr18Ni9Ti双金属复合材料.利用扫描电子显微镜(SEM)、电子探针(EPMA)、X射线衍射(XRD)、显微硬度(HV)等测试分析方法对双金属复合材料的两个连接界面及基体进行组织及性能分析.结果表明不锈钢-纯铜界面形成了宽为1.5 μm的互扩散区,但其过渡区无金属间化合物生成;铝/铜界面生成了宽约35 μm的扩散过渡区,过渡区的相组成为金属间化合物Al4Cu9,Al2Cu.     

Study of surface roughness and corrosion performance of Ni/Zn–Fe and Zn–Fe/Ni compositionally modulated multilayer coatings

Compositionally modulated multilayer coatings consisting alternative layers of nickel and zinc–iron alloy were electroplated using dual bath technique. The coating's surface morphology was studied using a scanning electron microscope. The effects of coatings configuration, i.e., order and the number of layers on the coatings surface roughness was investigated. It was observed that as the number of layers increases in the different Ni/Zn–Fe CMM coatings, 2 and 4-layer Zn–Fe/Ni CMM coatings the final surface roughness is decreased due to the lower grain growth of zinc–iron individual layers. The coatings corrosion protection performance was evaluated using Tafel extrapolation, anodic polarization and salt spray tests. The results of corrosion study showed that all Ni/Zn–Fe and Zn–Fe/Ni CMM coatings, except the 8-layer Zn–Fe/Ni coating, had a better corrosion protection performance compared to the single layer zinc–iron alloy coating or nickel coating.     

调制周期对Cr/CrN纳米多层膜的结构与性能的影响

采用多弧离子镀技术在65Mn钢表面制备了不同调制周期的Cr/CrN纳米多层膜.采用俄歇能谱仪(AES)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)、纳米硬度仪、轮廓仪和划痕仪,分析了不同调制周期Cr/CrN纳米多层膜的成分分布、微观结构、力学性能、残余应力和结合强度.结果表明,Cr/CrN纳米多层膜的表面平整致密,截面层状调制结构清晰,其调制结构为Cr层-过渡层-CrN层的"三明治"结构,调制比约为1∶ 1.多层膜由CrN、Cr2N和Cr相组成,在CrN(200)方向上出现择优取向.当调制周期为80 nm时,多层膜的硬度值相对较高.随调制周期的增大,Cr/CrN多层膜的残余应力值减小,结合强度值先增大后减小.当调制周期为120 nm时,涂层的划痕临界载荷值相对较高,为69 N.