Glancing Angle X-ray Diffraction Techniques Research Articles

Electrochemical noise energy generated by nickel electroplating process

AbstractThe effects of current density (Jk) and bath temperature on the structure of deposition layer of nickel and electrochemical noise energy (ED) are studied, and the relationship between the structure of the deposit and ED is also discussed in detail using electrochemical noise technique in coupled with the scanning electron microscopy and the glancing angle X-ray diffraction techniques. The results show that ED theoretically mainly reflects the severity or rate of the local cathodic reaction rather than the integral cathodic reaction, and is markedly influenced by the electroplating current density (Jk)-depended nucleation/growth kinetics of the nickel deposit film. The proceeding of the nucleation (or the formation of new phase)/growth process of crystal nucleus on a foreign substrate possesses much more effect on ED value than the subsequent homogenous growth of the already formed film particles, and the factors which can accelerate the drastic change of the electrode surface state should result in large ED value.

Structural investigation of Nd-zirconolite irradiated with He+ ions

Zirconolite, a potential candidate for the immobilization of actinides was investigated for the induced effects of α-particles simulated through ion beam irradiation. Nd-doped zirconolite pellets (Ca0.8Nd0.2ZrTi1.8Al0.2O7) synthesized through two step solid state sintering were irradiated with 30 keV He+ ions and analyzed for irradiation induced structural modulations through glancing angle X-ray diffraction technique. Diffraction patterns showed reduction in peak intensity and broadening of peaks with increasing fluence, indicating loss of crystallinity. Though zirconolite didn’t amorphize even upon irradiation at the maximum fluence used i.e. 1 × 1017 ions/cm2. Measured lattice strain enhanced with fluence, further suggesting distortion of the structure.

Effect of ion and neutron irradiation on oxide of PHWR fuel tube material

The effect of heavy ion irradiation on the stability of oxide phase of autoclaved Zircaloy 4 fuel tube material, has been studied using Glancing angle X-ray diffraction (GIXRD) technique after 306 KeV Ar+9 ions irradiation at a dose of 3 × 1019 Ar+9/m2. To estimate the extent of damage, a simulation was carried out using “Stopping and Range of Ions in Matter (SRIM-2008)” computer program based on the Monte Carlo method. For the first time, the oxide formed in 0n1 irradiated fuel tube after 7600 MWD/T burn up in Pressurized Heavy Water Reactor (PHWR) has been characterized using GIXRD technique. The advantage of this technique is that the stress-induced phase transformation, which normally occurs during metallographic sample preparation for optical and electron microscopy, is eliminated. The un-irradiated autoclaved oxide in the steam environment (415 °C and 500 °C), both uniform as well as nodular oxide has been characterized using GIXRD, X-ray photo-electron spectroscopy (XPS), scanning electron microscopy (SEM) attached with Energy Dispersive spectroscopy (EDS). Cross-sectional transmission electron microscopy has been carried out in uniform oxide before and after heavy ion irradiation. It is observed that heavy ion and neutron irradiation induce monoclinic to tetragonal phase transformation in the oxide. Presence of significant fraction of tetragonal ZrO2 phase as well as sub-oxide Zr3O has been identified in the oxide layer near oxide-coolant interface in 0n1 irradiated in-pile sample whereas in unirradiated autoclaved oxide these phases are present in a small fraction near the oxide-metal interface. XPS analysis indicates the difference in the chemical state of alloying element in the oxide when autoclaving is carried out at different temperatures.

Effect of low energy (keV) ion irradiation on structural, optical and morphological properties of SnO2–TiO2 nanocomposite thin films

RF Sputtering deposition technique was used to deposit the thin films of nanocomposite oxides as SnO2–TiO2 on Si and ITO coated glass substrate. As a target, SnO2–TiO2 was taken according to their molecular weight percent ratio of 3:1. Material modification has been induced by low energy ion beam with varying ion fluence from 5E13 to 5E16 ions/cm2. Glancing Angle X-ray Diffraction technique was used to study crystallite size, phase transformation and stability of different planes of pristine and irradiated thin films. The important peaks observed in XRD pattern were at angles 26.95°, 34.27°, 37.60°, 50.88° and 52.46°. The grain size distribution and surface morphology were studied by Atomic Force Microscopy technique in tapping mode. The results show that the grain size varies with ion fluence. Raman analysis revealed that the sharp peak at the frequency of 520 cm−1 ascribed to the T2g mode was observed for the pristine and lowest fluence irradiated film deposited on Si substrate. With increasing ion fluence, an opposite trend in SnO2 B2g peak was observed at nearly 775 cm−1 and the also peak bump was observed as a function of ion beam fluence. The optical band gap decreases from 3.90 to 3.63 eV due to the generation of ions and free radicals in valance band by varying ion fluence which was observed by UV/Visible Spectroscopy. The film thickness was determined to be 220 nm using Rutherford Backscattering Spectrometry. It also confirmed the absence of any impurities in the pristine and irradiated thin films. The material properties were mainly modified by the point defects and grain size growth arising due to nuclear energy loss.

Fabrication of superconducting tantalum nitride thin films using infrared pulsed laser deposition

The authors report the successful fabrication of superconducting tantalum nitride (TaN) thin films using a pulsed laser deposition technique with 1064 nm radiation. Films with thickness ∼100 nm deposited on MgO (100) single crystals and on oxidized silicon (SiO2) substrates exhibited a superconducting transition temperature of ∼8 K and 6 K, respectively. The topography of these films were investigated using atomic force and scanning electron microscopy, revealing fairly large area particulate free and smooth surfaces, while the structure of the films were investigated using θ-2θ and glancing angle x-ray diffraction techniques. For films grown on MgO a face-centered cubic phase of TaN was observed, while films grown on SiO2 exhibited the face-centered cubic as well as a mononitride hexagonal phase. The transition temperature of the TaN deposited on SiO2 was found to be more sensitive to the nitrogen pressure during deposition as compared to the TaN deposited on MgO.

Physical properties of high performance fluoride ion conductor BaSnF4 thin films by pulsed laser deposition

This article presents the results on the growth and characterization of BaSnF4 thin films on glass substrates prepared by pulsed laser deposition technique. The structural results of BaSnF4 thin film carried out by glancing angle X-ray diffraction technique indicates the formation of the film with similar structure (tetragonal, P4/nmm) to the bulk target material. The absorption coefficient and band gap of the film is determined by suitable analysis of the transmittance spectra. The transport properties of the thin films are studied using impedance spectroscopy in the temperature range of 323–573 K. The frequency-dependent imaginary part of impedance plot shows that the conductivity relaxation is non-Debye in nature. The scaling behavior of the imaginary part of impedance at various frequencies indicates temperature-independent relaxation behavior.

Diamond coatings on cemented tungsten carbide tools by low-pressure microwave CVD

Diamond coatings were deposited on commercial, cemented tungsten carbide tools of various cobalt content (3%, 6% and 12% Co) by low-pressure microwave CVD to assess the role of cobalt on the quality and adhesion (reliability) of diamond coatings. The samples were characterized by micro-Raman spectroscopy, scanning electron microscopy, and low angle X-ray diffraction. Problems associated with the detrimental effects of cobalt on the quality and adhesion of diamond coatings as well as the effect of cobalt at low and high substrate temperatures were investigated. Micro-Raman spectroscopy was used to assess the quality of the diamond coatings (phase purity as well as the amount of amorphous carbon associated with the sp 2 structure with increase in the concentration of Co in the WC tools) and the residual stresses on the tools. The presence of surface cobalt on the cemented tungsten carbide tools was established for the first time using the glancing angle X-ray diffraction technique. Various surface pretreatment techniques (removal of surface cobalt with aqua regia, Murakami treatment, and Murakami followed by ultrasonic microscratching with fine diamond suspension) were investigated with a view to enhance the mechanical adhesion of diamond coatings on to the cemented tungsten carbide. The morphology of diamond coatings was assessed using an SEM. Etching by Murakami followed by ultrasonic seeding with diamond particles generated isotropically rough surface which facilitated a strong mechanical anchoring in all directions of the diamond coating to the substrate. The diamond films deposited were qualitative assessed for adhesion using the Rockwell hardness tester with a Brale indenter. Significant improvement in the adhesion of diamond coatings on WC–3%, 6% and 12% Co tools were obtained by proper surface treatment and processing conditions.

Wear-induced phase transformation in yttria stabilized zirconia: X-ray photoelectron spectroscopic studies

X-ray photoelectron spectroscopy has been used to study near-surface phase transformation in yttria stabilized zirconia subjected to sliding wear. Characteristic differences are observed in the valence bands of the tetragonal and the monoclinic phases of zirconia. These valence bands have been used as ‘‘fingerprints’’ to monitor phase transformation during wear under different loading conditions. Conventional and glancing angle x-ray diffraction techniques were found inadequate to detect this phase transformation.

Diffusion barrier performance of pulsed laser deposited amorphous tungsten carbide films

The performance of pulsed laser deposited tungsten carbide films as diffusion barriers between a 〈100〉 Si substrate and an Al overlayer has been investigated. Four-point probe measurement of resistance is employed to monitor the electrical stability of the Al/WC/Si metallization schemes upon thermal annealing in a vacuum for 30 min in a temperature range from 100 to 500 °C. The Glancing angle x-ray diffraction technique has been used to characterize the as-deposited as well as annealed samples. To study the metallurgical interaction between Al overlayer and the barrier film, experiments on isothermal annealings are carried out. The data obtained have been used to estimate the activation energy for the formation of the intermetallic compound WAl12. Morphological features of the annealed samples have been obtained by employing the technique of scanning electron microscopy.

Investigation of the state of helium and radiation defects in He-irradiated nickel and copper by glancing angle X-ray diffraction

Abstract Damage caused by low energy helium implantation in nickel and copper has been investigated for the first time by glancing angle X-ray diffraction technique. The damage confined only to the near surface region, typically few thousands A, comprises of displacement type damage and implanted species. As X-ray penetration depth (for 99% absorption) can be continuously varied as a function of angle of incidence and X-ray wavelength, accurate lattice parameter measurements (back-reflection) can be used to obtain cumulative information regarding long- and short-range strain field of defects. High purity nickel and copper foils were irradiated at room temperature with 100 keV helium ions to fluence levels ranging from 1016 to 1018 ions/cm2. The results show: (a) simultaneous presence of two defect complexes of opposite strain field character in both nickel and copper, (b) mobility of vacancies is an important parameter for determining the nature and the strength of defect complex, and (c) local strains du...

Epitaxial Growth Of Nickel and Cobalt Germanides On Germanium

ABSTRACTTransmission and scanning electron microscopy, Rutherford backscattering-channeling and Read camera glancing angle x-ray diffraction techniques have been applied to study the epitaxial growth of nickel and cobalt germanides on germanium.NiGe, Co5Ge7 and CoGe2 were found to grow epitaxially on both (001) and (111)Ge. More extensive epitaxy on (111)Ge is correlated with better lattice matches at the germanide/Ge interfaces than those on (001)Ge for these epitaxial germanides.

Intermetallic compound formations in titanium-copper thin-film couples

Formation of intermetallic compounds in Ti-Cu thin film bilayer samples has been studied between 300–475 °C by Rutherford backscattering and glancing-angle x-ray diffraction techniques. The first intermetallic compound to be formed was TiCu and was followed by TiCu3, the latter showed detectable deviations from the stoichiometry. The thickening of both compounds obeyed a parabolic relationship with time. The interdiffusion coefficient derived from compound formation can be described by the following expressions: TiCu:D=4.85×10−4 exp(—1.48eV/kT) cm2/sec, TiCu3:D=7.73×10−2 exp(—1.82eV/kT) cm2/sec.

Kinetics of phase formation in Au—A1 thin films

Abstract Phase formation was studied in Au-A1 thin films by means of MeV He+ back-scattering and glancing angle X-ray diffraction techniques. In the initial stages of compound formetion where both unreacted Au and unreacted A1 layers are present, the phases Au5Al2 and Au2Al are found. The end phases of the low-temperature treatments (150–300°C) are AuAl2 or Au4Al in the presence of only unreacted Al or Au, respectively. The kinetics of the growth of the Al-rich compounds follow a (time)1/2 dependence. The activation energies for the growth of Au2Al and AuAl2 are 1.0 and 1.2 eV, respectively.

An X-Ray Diffraction Study of the Transformation of Retained Austenite by Fracture

DURING an investigation of the structure of a hardened 1½ per cent chromium steel, the presence of a small amount of retained austenite was observed in the microstructure. Examination of this material by the glancing-angle X-ray diffraction technique revealed retained austenite on a surface mechanically polished and etched for micro-examination, whereas retained austenite could not be found on the surface of a fracture produced by fatigue, or on a freshly produced brittle fracture surface.