Papers by Keyword: Glancing Angle X-Ray Diffraction (GAXRD)

Abstract: We have developed a bottom-up growth technology for nanostructures from a Cu surface by Ar ion irradiation. Cu2O conical nano-/micro-protrusions have been nucleated and grown from the surface of a preoxidized Cu plate by Ar ion irradiation in low vacuum. In this study, the growth direction or preferred orientation of the protrusions was analysed using glancing angle X-ray diffraction (GAXRD) analysis and an X-ray diffraction pole figure (XRD-PF) measurement. The GAXRD patterns showed that the main phase of the product obtained by Ar irradiation was Cu2O, shown as the highest peak of Cu2O (111), and CuO was additionally formed. The intensity ratio of Cu2O (110) to Cu2O (111) increased as the X-ray incident angle decreased from 10.0 to 0.5 deg, which indicated that the basal plane of the protrusions including the substrate was (110). Additionally, the XRD-PF {011}<001> 3-D plots showed the <110> preferred orientation of the product. These results explain that the growth direction or preferred orientation of the Cu2O protrusions is mainly <110>. The growth direction of the protrusions was separated and confirmed as <110> by checking the electron backscatter diffraction pattern (EBSP) of each protrusion.

Abstract: Titanium foils were subjected to soaking in NaOH aqueous solutions in the concentration range 0.1 M to 10.0 M, followed by oxidation in the range 400°C to 800°C. The samples were characterised by glancing angle X-ray diffraction and Raman microspectroscopy. The results showed that the corrosion by NaOH solution resulted in: • Partial dissolution of the anatase passive oxidation layer • Partial dissolution of the underlying titanium foil • Formation of a TiO2-rich sodium titanate hydrogel (Na2O·mTiO2·nH2O) The subsequent oxidation of the hydrogel on the titanium substrate resulted in: • Recrystallisation of sodium titanate (Na2O·5TiO2) • Recrystallisation of the rutile polymorph of TiO2 The concentration of the NaOH solution was important in that it affected the dissolution or retention of the anatase passive oxidation layer, where lower concentrations (0.5 M and 1.0 M NaOH) resulted in a lower degree of dissolution in comparison to where higher concentrations (5.0 M and 10.0 M NaOH) were used.

Abstract: Rutile nano-powders were suspended in a solution of acetylacetone and iodine. The suspensions were electrophoretically deposited on titanium foil at a voltage range of 5-30 V over times of 5-120 s. The dried tapes then were sintered at 800°C for 2 h in flowing argon. Both the green and fired tapes were examined by field emission scanning electron microscopy, optical microscopy, X-ray diffraction, and Raman microspectroscopy. The thickness of the films depended on the voltage and the time of deposition. The sintered microstructures depended significantly on the thickness of the film, which was a function the proximity to the Ti/TiO2 interface. The interface is critical to the microstructure because it acts as the source of defect formation, which enhances sintering, grain growth, and grain facetting.

Abstract: Anodic oxidation has been used to make well adhered and porous (≤1 μm pore diameter) thin films of anatase on titanium using electrolytic solutions with combinations of H2SO4, H3PO4, and H2O2. The crystallinity, film thickness, and pore size and number increase with time and voltage. The voltage is limited to ~180 V by electrolysis and/or breakdown and the film thickness is ≤3 μm.

Abstract: Capability of the X-ray scattering for study of low-dimensional structures is illustrated on few examples. They are focused to the phase analysis, residual stress measurement, calculation of the stress-free lattice parameters, investigation of the anisotropic lattice deformation and preferred orientation in UN thin films. Further, the study of concentration profiles in functionally graded hard-metals and investigation of the multilayer degradation caused by soft annealing are discussed.