Enhancement of the orientation and adhesion of Al films on LiNbO_3 with Ni underlayer

Al/Ni films were deposited on 128° Y-X LiNbO3 substrates by e-beam deposition. The influence of Ni underlayer on the microstructure, adhesion and resistivity of the Al/Ni films was investigated. It was found that Al films deposited on Ni underlayer thinner than 5 nm possessed strong texture. The textured Al/Ni films had a superior adhesion. Their resistivity decreased after annealing treatment at 200℃ for 30 min. With the textured Al/Ni films, a 2,30 GHz-range image-impedance connection SAW （Surface Acoustic Wave） filter was successfully fabricated.

Hydrogen storage properties of preferentially orientated Mg-Ni multilayer film prepared by magnetron sputtering

Mg-Ni multi-layer thin film was deposited on (001) Si wafer by magnetron sputtering with dual-target. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis reveal that the microstructure of the Mg-Ni multilayer thin film is composed of fine-crystalline Ni layer and crystalline [001] Mg layer. Hydrogenation process of the films were carried out by using the automatic gas reaction controller. The films undergone hydrogenation for different time were analyzed by XRD. The results show that hydrogenation properties of Mg with different preferential orientations are different. (002) diffraction peak of Mg disappears in compensating the appearing of the peaks of Mg2NiH4 and MgH2 in hydrogenation at 533 K, while the (101) peak still remains. The result reveals that the Mg film with (001) preferential orientation absorbs hydrogen at certain temperature easier than that of the Mg film with (101) orientation. This phenomenon can be explained in the view point of the energy change for the nucleation and growth of hydride in different crystal plane.

Ni-Cr薄膜换能组件静电响应特性与发火概率预测研究

针对电火工品在静电放电影响下可能发生误发火的问题,以Ni-Cr薄膜换能组件为研究对象,提出了一种分析其在人体静电放电下的响应特性,并预测发火概率的方法。首先,介绍了Ni-Cr薄膜换能组件系统架构,并建立了电火工品静电放电等效电路模型;其次,研究了Ni-Cr薄膜换能组件静电放电响应特性,分析了换能组件尺寸和放电电压对薄膜桥区温度的影响规律;最后,构建了Ni-Cr薄膜换能组件在统计特征下的输入条件,确定了换能组件失效判据,进而结合发火感度试验与数理统计方法,实现了在静电放电条件下电火工品发火概率的预测。研究结果表明:预测发火概率与试验值误差不超过5%,验证了本文方法的有效性。

Electrodeposition of Er-Ni Alloy Film in Dimethylsulfoxide

The cyclic voltammetry and chronoamperometry were used to investigate the electrochemical behaviors of Er(Ⅲ) and Ni(Ⅱ) in LiClO 4 DMSO(dimethylsufoxide) system on Pt and Cu electrodes. Experimental results indicated that the reduction of Er(Ⅲ) to Er and Ni(Ⅱ) to Ni were irreversible in one step on Pt and Cu electrodes. The diffusion coefficient and electron transfer coefficient of Er(Ⅲ) in 0.01 mol·L -1 ErCl 3 -0.1 mol·L -1 LiClO 4 DMSO system at 303K were 1.47×10 -10 m 2·s -1 and 0.108 respectively, and the diffusion coefficient and electron transfer coefficient of Ni(Ⅱ) in 0.01 mol·L -1 NiCl 2-0.1 mol·L -1 LiClO 4 DMSO system at 303K were 3.38×10 -10 m 2·s -1 and 0.160 respectively. The homogeneous, strong adhesive Er Ni alloy films with metallic lu- stre was prepared by potentiostatic electrolysis on Cu electrode in ErCl 3 NiCl 2 LiClO 4 DMSO system at -1.90～ -2.55 V (vs SCE).

Improvement of Joint Strength of SiCp/Al Metal Matrix Composite in Transient Liquid Phase Bonding Using Cu/Ni/Cu Film Interlayer

The compact oxide on the surface of SiCp/Al metal matrix composite （SiCp/Al MMC） greatly depends on the property of the joint. Inlaid sputtering target was applied to etch the oxide completely on the bonding surface of SiCp/Al MMC by plasma erosion. Cu/Ni/Cu film of 5μm in thickness was prepared by magnetron sputtering method on the clean bonding surface in the same vacuum chamber, which was acted as an interlayer in transient liquid phase （TLP） bonding process. Compared with the same thickness of single Cu foil and Ni foil interlayer, the shear strength of 200 MPa was obtained using Cu/Ni/Cu film interlayer during TLP bonding, which was 89.7% that of base metal. In addition, homogenization of the bonding region and no particle segregation in interfacial region were found by analysis of the joint microstructure. Scanning electron microscopy （SEM） was used to observe the micrograph of the joint interface. The result shows that a homogenous microstructure of joint was achieved, which is similar with that of based metal.

The effect of deposition temperature on the intermixing and microstructure of Fe/Ni thin film

The physical vapour deposition of Ni atoms on α-Fe（001） surface under different deposition temperatures were simulated by molecular dynamics to study the intermixing and microstructure of the interracial region. The results indicate that Ni atoms hardly penetrate into Fe substrate while Fe atoms easily diffuse into Ni deposition layers. The thickness of the intermixing region is temperature-dependent, with high temperatures yielding larger thicknesses. The deposited layers are mainly composed of amorphous phase due to the abnormal deposition behaviour of Ni and Fe. In the deposited Ni-rich phase, the relatively stable metallic compound B2 structured FeNi is found under high deposition temperature conditions.

Electrodeposition of Ni-SiC nanocomposite film

The point of zero charge(PZC) of SiC nanoparticles was determined by means of standard potentiometric titration method, while the influences of the main technological parameters on the microstructure of electrodeposited Ni-SiC composite film were studied and optimized. The results show that high bath pH value favors SiC nanoparticles negatively charged and high bath temperature promotes them positively charged. Under the experimental conditions, sodium dodecyl-glycol is proven to be an effective surface modification anionic surfactant for SiC nanoparticles. The results also show that the optimized Ni-SiC composite film is composed of the nanoparticles with the average grain size in the nanometer range (100 nm), and SiC nanoparticles disperse into the nickel matrix uniformly.

Electro-Deposition of Ni-La Film in Urea-NaBr Melt and Its Hydrogen Evolution Properties

The Ni-La alloy was electro-deposited in urea-NaBr melt. The codeposition behavior and effect of the cathodic current density on the coating composition were examined. As a result, lanthanum codeposited with nickel to form Ni-La alloy under the inducement effect of nickel. With the increase of the cathodic current density, the content of lanthanum of the deposit rose at first, then decreased, and reached the maximal value (10.3%(atom fraction)) at the current density 15 mA·cm-2. The crystallization behavior of Ni89.7La10.3 coating was investigated by means of differential scanning calorimetry and X-ray diffraction. The structure of Ni89.7La10.3 as-plated coating was amorphous phase. The amorphous phase was converted into center cubic close packed Ni-La (Fm3m) solid solution at 469.8 ℃. The electro-catalytic activity of hydrogen evolution of Ni89.7La10.3 coating was studied using electrochemical experiments, the results showed that the electro-catalytic activity of hydrogen evolution of Ni89.7La10.3 coating was better than that of nickel.

Electrochemical Preparation of La-Ni Alloy Film in Acetamide-Urea-NaBr Melting System

The reduction of Ni(Ⅱ) is an irreversible reaction and La(Ⅲ) cannot be reduced to La directly but be co-deposited inductively in the present of Ni(Ⅱ) in the Acetamide-Urea-NaBr molten salt electrolyte at 353 K. The uncrystallized alloy film of La-Ni is obtained by potentiostatic electrolysis, and the amount of La grows with increasing cathodic overpotential, molar ratios of La(Ⅲ) to Ni(Ⅱ) and the electrolysis time. The maximum amount of La in alloy film reaches to 78.81% (mass fraction) in present study.

Magnetic properties and structure of Ni_80Fe_20/Ni_48Fe_12Cr_40 bilayer films deposited on SiO_2/Si(100) by electron beam evaporation

Ni80Fe20/Ni48Fe12Cr40 bilayer films and Ni80Fe20 monolayer films were deposited at room temperature on SiO2/Si（100） substrates by electron beam evaporation. The influence of the thickness of the Ni48Fe12Cr40 underlayer on the structure, magnetization, and magnetoresistance of the Ni80Fe20/Ni48Fe12Cr40 bilayer film was investigated. The thickness of the Ni48Fe12Cr40 layer varied from about 1 nm to 18 nm while the Ni80Fe20 layer thickness was fixed at 45 nm. For the as-deposited bilayer films the introducing of the Ni48Fe12Cr40 underlayer promotes both the （111） texture and grain growth in the Ni80Fe20 layer. The Ni48Fe12Cr40 underlayer has no significant influence on the magnetic moment of the Ni80Fe20/Ni48Fe12Cr40 bilayer film. However, the coercivity of the bilayer film changes with the thickness of the Ni48Fe12Cr40 undedayer. The optimum thickness of the Ni48Fe12Cr40 underlayer for improving the anisotropic magnetoresistance effect of the Ni80Fe20/Ni48Fe12Cr40 bilayer film is about 5 nm. With a decrease in temperature from 300 K to 81 K, the anisotropic magnetoresistance ratio of the Ni80Fe20 （45 nm）/Ni48Fe12Cr40 （5 nm） bilayer film increases linearly from 2.1% to 4.8% compared with that of the Ni80Fe20 monolayer film from 1.7% to 4.0%.

Crystallization Kinetics of NiTi Films with Different Ni Contents

Three kinds of NiTi films with different Ni contents were prepared by DC magnetron sputtering. The crystallization kinetics of amorphous films was determined by using non-isothermal single- scan techniques. The results show that the activation energy of crystallization of Ni-rich NiTi film(Ni 51.10 at. pct, Ti 48.90 at. pct) is 715 kJ/mol; while that of Ti-rich films are similar: one is 445 kJ/mol (Ni 46.74 at. pct. Ti 53.26 at. pct), the other is 418 kJ/mol (Ni 43.21 at. pct, Ti 56.7g at. pct), which i5 lower than Ni-rich film. The Avrami parameter n of different films are 0.92 and 0.74 for Ni-rich film and Ti-rich films, respectively. The difference of kinetic parameters for NiTi films with various Ni contents implies that the crystallization behaviors of these films are distinct, which is confirmed by the calculated isothermal kinetics at different temperatures. The thorough research on this phenomenon is in progress.

Evolution of magnetic domain structure of martensite in Ni–Mn–Ga films under the interplay of the temperature and magnetic field

Ferromagnetic shape memory Ni-Mn-Ga films with 7M modulated structure were prepared on MgO （001） substrates by magnetron sputtering. Magnetization process with a typical two-hysteresis loop indicates the occurrence of the reversible magnetic field-induced reorientation. Magnetic domain structure and twin structure of the film were controlled by the in- terplay of the magnetic and temperature field. With cooling under an out-of-plane magnetic field, the evolution of magnetic domain structure reveals that martensitic transformation could be divided into two periods： nucleation and growth. With an in-plane magnetic field applied to a thermomagnetic-treated film, the evolution of magnetic domain structure gives evidence of a reorientation of twin variants of martensite. A microstructural model is described to define the twin structure and to produce the magnetic domain structure at the beginning of martensitic transformation; based on this model, the relationship between the twin structure and the magnetic domain structure for the treated film under an in-plane field is also described.

贴膜式Ni-Cr换能元设计及性能研究

通过热压工艺将5μm的Ni-Cr薄膜附着在聚酰亚胺薄膜上制备了贴膜式Ni-Cr薄膜,采用激光刻蚀加工工艺制备了贴膜式Ni-Cr换能元电桥,仿真优化设计了蝶形、S形换能元电桥,并开展了2种形状电桥的贴膜式Ni-Cr换能元的伏安特性、最大不熔断电流、50 ms脉冲恒流电爆特性以及发火特性试验研究。研究结果表明:桥区长度为3 mm的换能元电桥在1 A 5 min恒流激励后桥区温度最低;贴膜式Ni-Cr换能元在33μF电容放电时,随着充电电压的升高断桥时间缩短,蝶形和S形未发生断桥的电压分别为16,20 V;蝶形和S形换能元在5 min恒流脉冲输入下的最大不熔断电流分别为1.3,1.2 A;在50 ms脉冲恒流电爆时,随着施加电流幅度的不断增加,其工作电压也不断增高,其断桥时间越来越短,S形换能元和蝶形换能元分别在2.4,2.3 A时电桥未发生爆炸;33μF、28 V电容放电下贴膜式Ni-Cr换能元可以点燃斯蒂芬酸铅,并正常发火。

Transformation behaviors,structural and magnetic characteristics of Ni-Mn-Ga films on MgO(001)

Ferromagnetic Ni-Mn-Ga films were fabricated by depositing on MgO （001） substrates at temperatures from 673 K to 923 K. Microstructure, crystal structure, martensitic transformation behavior, and magnetic properties of the films were studied. With increasing deposition temperature, the surface morphology of the films transforms from granular to continu- ous. The martensitic transformation temperature is not dependent on deposition temperature; while transformation behavior is affected substantially by deposition temperature. X-ray analysis reveals that the film deposited at 873 K has a 7M marten- site phase, and its magnetization curve provides a typical step-increase, indicating the occurrence of magnetically induced reorientation （MIR）. In situ magnetic domain structure observation on the film deposited at 873 K reflects that the marten- sitic transformation could be divided into two periods： nucleation and growth, in the form of stripe domains. The MIR occurs at the temperature at which martensitic transformation starts, and the switching field increases with the decrease of temperature due to damped thermal activation. The magnetically induced martensitic transformation is related to the difference of magnetization between martensite and austenite. A shift of martensite temperature of dT/dH = 0.43 K/T is observed, consistent with the theoretical value, 0.41 K/T.

Morphology Structure and Electrical Properties of NiCr Thin Film Grown on the Substrate of Silicon Prepared by Magnetron Sputtering

NiCr micron-resistor was designed and prepared by magnetron sputtering and lithography on the substrate of silicon with different powers. It is found that there exists a big gap in the TCR between the annealed group and the un-annealed group. A series of tests were made to figure out the reasons lying behind the gap in the TCR between the annealed group and the un-annealed group. UV reflection results show that there is no increase in the concentration of free electrons after annealing. However, the data obtained from XRD reveal that the annealing does not have an obvious influence on the strain of thin films, but really increases the grain size of thin films. Therefore, the grain boundary scattering plays a dominant role in explaining the obvious difference in the TCR. Finally through appropriate methods, a micron-resistor for heating-up with a low TCR value was obtained.

Oxygen Evolution at Nickel Hydroxide Films Co deposited Light Rare Earth Elements

Composite nickel hydroxide films were prepared by cathodic co electrodeposition from metal nitrate solution and characterized by cyclic voltammetry in 1.0 mol/L KOH solution. The codeposited light rare earth elements were lanthanum, cerium, praseodymium and neodymium. The films were analyzed by spectrophotometry and optical transmission. The results of the cyclic voltammetry in 1.0 mol/L KOH solution showed that the current density for oxygen evolution at the film electrode was affected by the co deposited rare earth metal ions in the film. About 20 mA/cm 2 increase of current density for oxygen evolution was found when the film was obtained from the solution with cerium (7% v/v) and nickel (93% v/v) nitrate. The effects of galvanostatic cathodic current density for the film formation on the oxygen evolution at the film electrodes from the alkaline were discussed.

Mg-Ni THIN FILM-A POTENTIAL NEGATIVE ELECTRODE FOR NIKEL-METAL HYDRIDE BATTERY

Mg-Ni thin films for nickel-metal hydride (Ni-MH) battery negative electrode were prepared on three different substrates by using magnetron sputtering with compacted Ni and Mg mixture powder. The microstructure of Mg-Ni thin films deposited on the glass and the Ni foil substrate respectively was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the Mg-Ni thin films were in amorphous structure and the composition of the thin film was homogeneous. Electrochemical measurement show the discharge capacity of the thin film negative electrode deposited on the foam Ni substrate was 284.8mAh/g in 6M alkaline electrolyte and the internal resistance was much lower than that of the electrode prepared by the ball-milled powder during the charge-discharge cycle.

Oxidation Behavior of Fe26Cr1Mo Stainless Steel in the Presence of Ni-La_2O_3 Electrodeposited Composite Film

The oxidation behaviors of Fe26Cr1Mo with and without the Ni La 2O 3 electrodeposited composite film have been investigated by thermogravimetric analysis (TGA) and a scanning electron microscope equipped with an energy dispersive analytical X ray system(SEM/EDAX). The experimental results show that the oxide scale growing on Fe26Cr1Mo exposed at 900 ℃ spalled severely during cooling, while after the stainless steel was coated with the Ni La 2O 3 electrodeposited composite film, its high temperature cyclic oxidation resistance was significantly improved. The reason is that a La 2O 3 modified NiO scale, which has a superior adhesion to the substrate, was formed on the Fe26Cr1Mo stainless steel coated with Ni La 2O 3 composite film.

Electrochemical investigation on the formations of Dy-Ni alloy films in dimethylformamide

The elexctrochemical properties of Dy (III), Ni(II) + Ni(II) indimethylformamide were studied by cyclic voltammetry on Pt or Cuelectrode. Black, metallic lustered, compact and well adhesive Dy-Nialloy films can be co-deposited on Cu electrode bysweeping-potential-deposition method within some potentials. SEM,EDAX and XRD were used to analyze the alloy films. The Dy content inthe Dy-Ni alloy film is up to 56.91/100 (mass fraction) and the Dy-Ni alloy films are amorphous.

Protective Characteristics and Formation Mechanism of the Corrosion Product Films of B30 Tubes Exposed to Seawater

The corrosion product films of two kinds of B30 tubes(similar to CDA 715)exposed to seawat- er for various periods of time were investigated by SEM,AES and XPS.The results show that the pro- tective corrosion product film is thin,uniform and adherent.FeOOH is found to be present in the film surface,which confirms the hypothesis that iron hydroxide segregates at the surface of the film.The FeOOH promotes Ni enrichment in the corrosion layer by preventing Ni from running off.The corro- sion product film with no protectiveness is of lay- ered structure,loose and bad adherence.The for- mer film is formed through direct oxidation and the latter by precipitation and redeposition from dis- solved species.