Properties of oxide films grown on 25Cr20Ni alloy in air-H_2O and H_2-H_2O atmospheres

The oxidation kinetics,surface morphology and phase structure of oxide films grown on 25Cr20Ni alloy in air-H2O and H2-H2O atmospheres at 900 ℃ for 20 h were investigated.The anti-coking performance and resistance to carburization of the two oxide films were compared using 25Cr20Ni alloy tubes with an inner diameter of 10 mm and a length of 850 mm in a bench scale naphtha steam pyrolysis unit.The oxidation kinetics followed a parabolic law in an air-H2O atmosphere and a logarithm law in a H2-H2O atmosphere in the steady-state stage.The oxide film grown in the air-H2O atmosphere had cracks where the elements Fe and Ni were enriched and the un-cracked area was covered with octahedral-shaped MnCr2O4 spinels and Cr1.3Fe0.7O3 oxide clusters,while the oxide film grown in the H2-H2O atmosphere was intact and completely covered with dense standing blade MnCr2O4 spinels.In the pyrolysis tests,the anti-coking performance and resistance to carburization of the oxide film grown in the H2-H2O atmosphere were far better than that in the air-H2O atmosphere.The mass of coke formed in the oxide film grown in the H2-H2O atmosphere was less than 10％ of that in the air-H2O atmosphere.The Cr1.3Fe0.7O3 oxide clusters converted into Cr23C6 carbides and the cracks were filled with carbon in the oxide film grown in the air-H2O atmosphere after repeated coking and decoking tests,while the dense standing blade MnCr2O4 spinels remained unchanged in the oxide film grown in the H2-H2O atmosphere.The ethylene,propylene and butadiene yields in the pyrolysis tests were almost the same for the two oxide films.

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.

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.

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.

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.

HIGH CONDUCTIVITIES OF LANGMUIR-BLODGETT FILMS OF TBT-TTF-NI(DMIT)_2/STEARIC ACID

Conductivities of Langmuir-Blodgett(LB) films of tetrabenzylthio- tetra-thiafulvalence-Ni(dmit)_2/stearic acid (SA)were described. This charge transfer complex was transferred with SA onto a glass plate coated with A1 electrodes. The relation of conductivities of LB films with molar ratio of SA was studied. The conductivities of LB films of TBT-TTF-Ni(dmit)_2/SA were measured under undoped and I_2 doped states. The maximum conductivity () of LB film was 40s/cm.

Effect of annealing on the characteristics of Au/Ni_(50)Fe_(50) bilayer films grown on glass

Sputter-deposited Au/NisoFeso bilayer films were annealed in a vacuum of 5×10^-4 Pa at 523 to 723 K for 30 or 90 min. The characteristics of the bilayer films were determined by Auger electron spectroscopy, field emission scanning electron microscopy, X- ray diffractometry, a four-point probe technique, and an alternating gradient magnetometer. When the annealing temperature and time reached 723 K and 90 min, Ni and Fe atoms markedly diffused into the Au layer. The grain size of the Au layer did not change markedly with the annealing condition. As the annealing time was 30 min and the annealing temperature exceeded 573 K, the resistance of the bilayer film increased with increasing the annealing temperature. Furthermore, the resistance of the bilayer film annealed at 723 K for 90 ,nin was lower than that of the bilayer film annealed at 723 K for 30 min. All the bilayer films showed magnetic hysteresis loops. The as-deposited bilayer film showed a hard magnetization. The bilayer film represented an easy magnetization with increasing the annealing temperature. The Au/Ni50Fe50 film that annealed at 723 K for 90 min had the lowest saturation magnetization.

Porosity Evaluation and the Power Spectral Densities Analyses of Carbon-Nickel Composite Films Annealed at Different Temperatures

The densification and the fractal dimensions of carbon-nickel films annealed at different temperatures 300, 500, 800, and 1000℃ with emphasis on porosity evaluation are investigated. For this purpose, the refractive index of films is determined from transmittance spectra. Three different regimes are identified, T 〈 500℃, 500℃ 〈 T 〈 800℃ and T 〉 800℃. The Rutherford baekscattering spectra show that with increasing the annealing temperature, the concentration of nickel atoms into films decreases. It is shown that the effect of annealing temperatures for increasing films densification at T 〈 500℃ and T 〉 800℃ is greater than the effect of nickel concentrations. It is observed that the effect of decreasing nickel atoms into films at 500℃ 〈 T 〈 800℃ strongly causes improving porosity and decreasing densification. The fractal dimensions of carbon-nickel films annealed from 300 to 500℃ are increased, while from 500 to 1000℃ these characteristics are decreased. It can be seen that at 800℃, films have maximum values of porosity and roughness.

Nickel Antimony Sulphide Thin Films for Solar Cell Application: Study of Optical Constants

Chemical bath deposition technique has been used to deposit Ni-doped Sb2S3 thin films onto glass substrate. Doping was carried out by adding 1, 3 and 5 wt% of Ni. Bath temperature was kept as 10℃ and films were annealed at 250℃ under vacuum. Polycrystalline nature of films with an orthorhombic phase was analyzed by X-ray diffraction technique. Scanning electron microscopy was used for morphological study which shows that grains are spherical. Optical measurements using transmittance data indicated that films have a direct band gap of 1.00 - 2.60 eV with an absorption coefficient of ~104 cm-1 in visible range. The average value of electrical conductivity was calculated as 1.66, 1.11 and 1.06 (Ω·cm)-1 for as-deposited films and 1.90, 2.08 and 1.15 (Ω·cm)-1 for annealed films while refractive indices were found as 2.18 - 3.38 and 1.91 - 3.74 respectively. The obtained films can be used for solar cell applications due to their good absorbing properties like higher absorption coefficient and refractive index values.

Effect of Nickel Distributions Embedded in Amorphous Carbon Films on Transport Properties

Electrical properties of C/Ni films are studied using four mosaic targets made of pure graphite and stripes of nickel with the surface areas of 1.78,3.21,3.92 and 4.64%.The conductivity data in the temperature range of400-500 K shows the extended state conduction.The conductivity data in the temperature range of 150-300 K shows the multi-phonon hopping conduction.The Berthelot-type conduction dominates in the temperature range of 50-150 K.The conductivity of the films in the temperature range about 〈 50 K is described in terms of variable-range hopping conduction.In low temperatures,the localized density of state around Fermi level（F）for the film deposition with 3.92% nickel has a maximum value of about 56.2×10^（17）cm^（-3）eV^（-1） with the minimum average hopping distance of about 3.43 × 10^（-6） cm.

Magnetic Properties of NiCuZn Ferrite Thin Films Prepared by the Sol-gel Method

Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing （RTA）, and their magnetic properties and crystalline structures were investigated. The samples calcined at and above 600 ℃ have a single-phase spinel structure and the average grain size of the sample calcined at 600 ℃ is about 20 nm. The initial permeability μi, saturation magnetization M and coercivity H of the samples increase with the increasing calcination temperature. The sample calcined at 600 ℃ exhibits an excellent soft magnetic performance, which has μi=33.97 （10 MHz）, Hc=15.62 Oe and Ms=228.877 emu/cm^3. Low-temperature annealing can enhance the magnetic properties of the samples. The work shows that using the sol-gel method in conjunction with RTA is a promising way to fabricate integrated thin-film devices.

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.

Interface between metallic film from Fe-Ni-C system and HPHT as-grown diamond single crystal

Microstructures of surface layer (near diamond) of the metallic film from Fe Ni C system are composed of (Fe,Ni) 3C, (Fe,Ni) 23 C 6 and γ (Fe,Ni), from which it can be assumed that graphite isnt directly catalyzed into diamond through the film and there exists a transition phase (Fe,Ni) 3C that can decompose into diamond structure. AFM morphologies on the film/diamond interface are traces preserved after carbon groups moving from the film to diamond. The morphologies on the as grown diamond are similar to those on corresponding films, being spherical on (100) face and sawtooth like steps on (111) face. Diamond growth rates and temperature gradients in boundary layer of the molten film at HPHT result in morphology differences.

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.

EFFECT OF HEAT TREATMENTS ON THE MICROSTRUCTURE AND TRANSFORMATION CHARACTERISTICS OF TiNiPd SHAPE MEMORY ALLOY THIN FILMS

Microstructure and phase transformation behaviors of the film annealed at different temperatures were studied by X-ray diffractometry （XRD）, transmission electron microscopy and differential scanning calorimeter （DSC）. Also tensile tests were examined. For increasing annealed temperature, multiple phase transformations, transformations via a B19-phase or direct martensite/austenite transformtion are observed. The TiNiPd thin film annealed at 750℃ had relatively uniform martensite/austenite transformtion and shape memory effect. Martensite/austenite transformtion was also found in strain-temperature curves. Subsequent annealing at 450℃ had minor effect on transformation temperatures of Ti-Ni-Pd thin films but resulted in more uniform transformation and improved shape memory effect.

热处理温度对Fe-Ni合金薄膜微结构及磁性的影响

采用直流电沉积法在硫酸盐-氯化物镀液中制备了Fe-44wt％Ni纳米晶合金薄膜。通过原子力显微镜（AFM）、X射线衍射（XRD）、透射电子显微镜（TEM）以及开路磁测量装置，对Fe-44wt％Ni合金薄膜镀态和退火态样品的微结构和磁性能进行测量。结果表明：退火温度升高能够降低薄膜内应力，使薄膜结晶均匀，但对薄膜晶粒尺寸和磁性能影响很大。Fe-44wt％Ni合金薄膜是由γ-（Fe，Ni）相和α-（Fe，Ni）相构成。在250℃真空退火处理1h后Fe-44wt％Ni合金薄膜的晶粒尺寸在20～30nm之间，且具有良好的软磁性能，饱和磁感应强度BS为1．06T，矫顽力HC为40A／m。

Er-Fe-Ni合金膜在二甲基亚砜中电化学制备的研究

利用循环伏安法和恒电位电解法研究了室温条件下在LiClO4 DMSO (二甲基亚砜 )体系中Er Fe Ni合金膜的电化学制备 ,实验结果表明 :在 0 .1mol·L- 1 ErCl3 0 .1mol·L- 1 FeCl2 0 .1mol·L- 1 NiCl2 0 .1mol·L- 1 LiClO4 DMSO体系中 ,控制电位在 -2 .0 0V～ -2 .60V范围内进行恒电位电解 ,可得到表面均匀、附着力强、有金属光泽的黑色非晶态Er Fe Ni合金膜 ,其中稀土Er的质量百分含量可达 3 1.3 9%～ 41 63 %。

模板辅助电化学沉积三维有序大孔Fe-Ni合金膜

三维有序大孔磁性材料在光子晶体和新功能磁性材料方面具有潜在优势.采用电化学沉积方法制备三维有序大孔Fe-Ni合金,将聚苯乙烯(PS)微球在ITO导电玻璃上自组装高度有序的胶体晶体阵列作为模板,向模板空隙中电沉积Fe-Ni合金,去除PS模板后获得六方密排多孔结构的Fe-Ni合金薄膜.采用金相显微镜和扫描电子显微镜对多孔薄膜的微观结构进行表征,结果表明,多孔薄膜孔径的大小由模板聚苯乙烯微粒的粒径决定,不同孔径的薄膜由于布拉格衍射呈现出不同的颜色.通过调整沉积时间和沉积温度可以控制有序大孔材料的结构和厚度.