添加剂的吸附行为及其对Ni沉积层性能的影响

采用电化学及X射线衍射等方法研究有机添加剂苯磺酸钠、苯亚磺酸钠和糖精的吸附作用及其对Ni电沉积层的电化学活性、晶粒尺寸、织构及显微硬度的影响．结果表明，苯亚磺酸钠和糖精使Ni沉积层的电化学活性提高，（111）晶面的织构系数明显增大，而使（290）晶面的织构系数减小，还导致沉积层的晶粒尺寸显著减小和显微硬度提高；然而，苯磺酸钠对沉积层的活性及织构影响很小．讨论了上述添加剂的作用．     

A study on the orientation inheritance in laminated NiAl produced by in situ reaction annealing

In order to promote the performance of B2 NiAl by texture control of orientation during in situ processing, phase transformation in laminated NiAl with bimodal grain size distribution manufactured by reaction annealing of Ni and Al foils has been studied. It turned out that there existed a Kurdjumov–Sachs orientation relationship (K–S OR) between parent Ni and product NiAl by crystallography analysis according to the electron backscatter diffraction (EBSD) results. The parent Ni did not transform to the product NiAl directly but via the formation of Ni₃Al firstly according to the transmission electron microscope (TEM) observation of the interface. This led to a new K–S OR between Ni₃Al and NiAl with a small atomic misfit, which made less residual stress generated through the formation of Ni₃Al than directly from the parent Ni.     

Textured nickel tapes prepared from commercially available material

Textured Ni tapes were fabricated from commercially available nickel pellets (98.5% Ni). Ingots produced by a melt process were cold rolled to 150–400 μm thick tapes. Texturing was achieved by annealing in a reducing atmosphere (Ar + 6.5% v/v H₂). Sharp cubic biaxial textured Ni tapes were obtained by thermal treatment at 1000°C for 2 hours in a reducing atmosphere. The tapes were characterized by scanning electron microscopy, X-ray diffraction and by electron backscattering diffraction. The tensile strength, the thermal expansion behavior and the Vickers hardness for the cold rolled tapes and for the heat-treated tapes were measured.      

Investigation of microstructure evolution during self-annealing in thin Cu films by combining mesoscale level set and ab initio modeling

Microstructure evolution in thin Cu films during room temperature self-annealing is investigated by means of a mesoscale level set model. The model is formulated such that the relative, or collective, influence of anisotropic grain boundary energy, mobility and heterogeneously distributed stored energy can be investigated. Density functional theory (DFT) calculations are performed in the present work to provide the variation of grain boundary energy for different grain boundary configurations. The stability of the predominant (111) fiber texture in the as-deposited state is studied as well as the stability of some special low-Σ grain boundaries. Further, the numerical model allows tracing of the grain size distribution and occurrence of abnormal grain growth during self-annealing. It is found that abnormal grain growth depends mainly on the presence of stored energy variations, whereas anisotropic grain boundary energy or mobility is insufficient to trigger any abnormal growth in the model. However, texture dependent grain boundary properties, mobility in particular, contribute to an increased content of low-Σ boundaries in the annealed microstructure. The increased presence of such boundaries is also promoted by stored energy variations. In addition, if the stored energy variations are sufficient the coexisting (111) and (001) texture components in the as-deposited state will evolve into a (001) dominated texture during annealing. Further, it is found that whereas stored energy variations promote the stability of the (001) texture component, anisotropic grain boundary energy and mobility tend to work the other way and stabilize the (111) component at the expense of (001) grains.     

Textures and physical properties of marbles deformed at 20 – 250°c

Abstract

The experimental equipment at beam line 7A of the IBR-2 pulsed reactor at JINR, which includes a texture diffractometer and a high-pressure device, is used to characterize textural and structural changes of marbles in dependence upon directed stress, temperature and time. It was shown, that texture changes as a consequence of heating are not valid, in contrast, long-acting load even at moderate stresses led to significant texture modification. The neutron diffraction data are also used to demonstrate its usefulness for the calculation of the thermal expansion coefficient a of calcite, and to calculate the lattice stresses induced by temperature and mechanical stresses.     

Simple technique for texture function analysis in granular thin film media

In this work a simple technique to extract the texture function in granular thin film media is implemented. The technique is based on previous work in which the distribution function of particles easy axes f(α) is calculated from the measured parallel remanence curve (M_rp(β)). In this simple technique we consider that the measured M_rp(β) curve can be fitted to a series of cos(2β), i.e. M_rp(β)=B₀+B₂ cos(2β)+B₄ cos(4β) where the angle β is the angle by which the film is rotated. This approximation is found to be valid when the texture function has a standard deviation >20°. On this basis, the constants B₀, B₂ and B₄ can be determined by using only three data points for the parallel remanence, M_rp(0), M_rp(45°) and M_rp(90°). The new technique is applied to a textured thin film consisting of cobalt ferrite particles 17 nm in diameter and to a commercial Sony video tape. Using this simple technique, the obtained texture functions are found to be similar to those obtained from the full M_rp(β) curves. This new technique will furnish a simple method with which the texture function in 2D systems can be obtained.     

Inverse Hall–Petch relation of nanostructured Ni films prepared by electrodeposition

We report the morphology, texture, mechanical properties of Ni films with nanosized grains prepared by electrodeposition as a function of current density. With an increase in current density, the morphology of the nanostructured films was greatly affected and the textures changed from face-centered cubic (1 1 1)- to (2 0 0)-orientation. Consequently, the textural and microstructural alteration exerted strong influence on the hardness of the films, leading to decrease in the hardness (in particular, the inverse Hall–Petch relation) as current density increased, attributed to the distribution of colonies of grain agglomerate and the variation of directional tensile strength.     

New method to measure whole-wavelength transmittance of TCO substrates for thin-film silicon solar cells

High transmittance of transparent conductive oxide (TCO) substrates is one of the most important factors for achieving high efficiency in thin-film silicon solar cells. Immersion (IM) method with CH₂I₂ liquid is widely used for the evaluation of optical properties (transmittance, reflectance and absorption) for TCO substrates with textured surface in order to reduce the scattering at the TCO surface. However, in order to measure transmittance accurately, three problems have been found. (1) CH₂I₂ liquid itself absorbs the light in short wavelength region. (2) The transmittance around the absorption edge of CH₂I₂ liquids is very sensitive to its amount. (3) Scattering cannot be suppressed when the scattering surfaces are more than 2 surfaces (for example, TCO on reactive ion etching (RIE) processed glass). To overcome these problems, we proposed a new setup to measure optical properties of TCO substrates by holding the samples inside the integral sphere. As the results, we have confirmed that their absorption in all wavelength could be measured accurately and the transmittance measured by the new method was well consistent with the external quantum efficiency (EQE) of the fabricated cell while the transmittance measured with conventional IM method showed differently. Therefore, this new method could be a useful tool to evaluate TCO substrates for thin-film silicon solar cells.     

Large magnetostriction and structural characteristics of Fe83Ga17 wires

The columnar-grained structure induced by directional solidification was beneficial to improve the deformability of Fe₈₃Ga₁₇ alloy. Fe₈₃Ga₁₇ wires with diameter of 0.5∼0.9 mm were prepared successfully by hot rotary swaging and warm drawing from the directional solidified rods. The magnetostriction and microstructure of the as-drawn and the annealed Fe₈₃Ga₁₇ wires with diameter of 0.6 mm were investigated. Results demonstrated that the magnetostriction of Fe₈₃Ga₁₇ wires depended on the microstructure and the fiber texture, which were controlled by heat treatment process. The maximum magnetostriction of 160 ppm was detected in the annealed wire, which has the ideal <100> fiber texture. The phase mixture of A2 containing heterogeneous modified-DO₃ phase has beneficial effect on magnetostriction.     

Effect of pulsed magnetic field annealing on the microstructure and texture of grain-oriented silicon steel

The effect of pulsed magnetic primary annealing on the microstructure and texture of two-stage cold-rolled silicon steel is investigated. Specimens are annealed at 700 °C for 1 h under a 1 T pulsed magnetic field along different directions with respect to the sample coordinate system. Crystallographic orientation and grain size are identified by analyzing electron backscattered diffraction pattern. The effects of magnetic field treatment are related to the magnetic field direction. Based on the anisotropy energy of ferromagnetic material during magnetic annealing, a hypothesis is proposed. All of the experimental results in this work support the proposed model.