X-ray Amorphous Structure Research Articles

A New and Simple Method for Manufacturing Electrochromic Tungsten Oxide Films

A new and simple method for the preparation of electrochromic tungsten oxide film is presented. This novel approach can be realized by introducing a nanoporous textured polyacrylic acid (PAA) layer between tungsten oxide layer and indium tin oxide (ITO) one by dip-coating process. Homogeneous film with a thickness of about 0.8 μm is made by single dipping a PAA-coated ITO glass in the WO3-NH4OH solution and shows an X-ray amorphous structure. During the cathodic and anodic processes by chronopotentiometry, the present films exhibit highly reversible electrochemical insertion of lithium ions; the corresponding inserted charge of 12.5 mC/cm2gives rise to a marked blue color yielding the change in optical density (AOD) of 0.65 at 550 nm and a coloration efficiency(η)of 51.8 cm2/C.

Investigation into the structure of electrodeposited nickel-phosphorus alloy deposits

This paper presents a study into the structure of NiP deposits containing 1.15–15.43 mass% P using X-ray diffraction. The coatings were deposited from electrolytes containing both phosphorous and phosphoric acids using conventional direct current. Samples obtained by electroless deposition were also examined for comparative purposes. The effects of composition on crystallite/grain size have been determined quantitatively using an X-ray diffraction line broadening technique and the formation of X-ray amorphous structures have also been followed using X-ray diffraction. The development of the amorphous phase, however, was found to be sensitive to crystallographic orientation. At amorphous contents above 70%, the crystalline nickel phase was associated only with (111) (222) orientations parallel to the surface of the deposits. This appeared to result from a decrease in the growth rate of other orientations, e.g. (200), relative to the (111) orientation.

Author index of volumes 61 and 62

Recently, it was found that the reactive magnetron sputtering of TiN films with the addition of small (≤ 10 at.%) amount of Fe makes it possible to change the preferred crystallographic orientation of grains in the film when the partial pressure of nitrogen pN2 in the sputtering gas is continuously increased. Between the films with different preferred crystallographic orientations there is a transition region (TR). The films produced inside TR are characterized by an X-ray amorphous structure. In spite of the fact that the films produced inside TR and outside of it strongly differ in their structure, both kinds of films exhibit an enhanced hardness [J. Musil, H. Polakova, J. Suna, J. Vlcek, Surf. Coat. Technol. 177–178 (2004) 289]. It was found that the enhanced hardness arises in two cases: (1) in the materials composed of a mixture of small grains of different crystallographic orientations, i.e. in the films produced inside TR, and (2) in the materials composed of nanocolumns perpendicular to the film/substrate interface, i.e. in the films produced outside TR. These findings are in an agreement with a new concept of nanocomposite phases with enhanced hardness based on the size of grains and the shape of crystallites [J. Musil, in: A. Cavaleiro, J.T.M. De Hosson (Eds.), Nanostructured Hard Coatings, Kluwer Academic/Plenum Publishers, New York, 2005, Chapter 10]. A development of mechanical properties of the Zr–Ni–N films with increasing pN2 is also discussed in detail.

Crystallization of Amorphous Metastable Ceramic PVD-Coatings

ABSTRACTCeramic PVD coatings have got very often an X-ray Amorphous structure. This is regarded for all classes of ceramics like covalent and ionic Materials. These Amorphous materials start to crystallize at temperatures about 800 °C, a quite low temperature for the practical use of such Materials. This prevents the propagation of this materials in applications like high temperature wear protection, oxidation resistivity etc.This paper describes several possible techniques to increase the thermal stability of the Amorphous state of ceramic PVD-coatings like A1203 and SiC up to 1200 °C. The best way is the incoporation of an additional element like nitrogen into the thin filmsl. The change of the mechanical properties of alumina leads to new applications like diffusion barriers.

A combined QEXAFS/XRD method for on-line, in situ studies of catalysts: Examples of dynamic measurements of Cu-based methanol catalysts

The development of a new in situ method which allows high quality XRD and EXAFS to be obtained on-line under ideal catalytic conditions is discussed. The possibility to obtain both types of information simultaneously enables a much better structural description of catalytic materials which typically contain both crystalline and X-ray amorphous structures. The system employs a capillary tube as the microreactor/in situ cell. The high degree of temperature uniformity of the cell and the possibilities of fast changes in reaction conditions make the system ideal for dynamic studies. For this purpose, the EXAFS measurements are carried out in the newly developed quick scanning mode (QEXAFS) which also allows high quality data to be obtained. The XRD is acquired using a position sensitive detector. The application of the setup for time resolved measurements is demonstrated in a study of the calcination and reduction of Cu-based methanol catalysts where the changes take place over a few degrees. The high quality of the data made it possible to obtain important new insight regarding the presence of intermediate phases during these processes. Studies of Cu/SiO2 catalysts show the advantages of a newly developed theory for a better estimation of coordination numbers (and thus particle sizes) from EXAFS.

Author index of volume 49

Recently, it was found that the reactive magnetron sputtering of TiN films with the addition of small (≤ 10 at.%) amount of Fe makes it possible to change the preferred crystallographic orientation of grains in the film when the partial pressure of nitrogen pN2 in the sputtering gas is continuously increased. Between the films with different preferred crystallographic orientations there is a transition region (TR). The films produced inside TR are characterized by an X-ray amorphous structure. In spite of the fact that the films produced inside TR and outside of it strongly differ in their structure, both kinds of films exhibit an enhanced hardness [J. Musil, H. Polakova, J. Suna, J. Vlcek, Surf. Coat. Technol. 177–178 (2004) 289]. It was found that the enhanced hardness arises in two cases: (1) in the materials composed of a mixture of small grains of different crystallographic orientations, i.e. in the films produced inside TR, and (2) in the materials composed of nanocolumns perpendicular to the film/substrate interface, i.e. in the films produced outside TR. These findings are in an agreement with a new concept of nanocomposite phases with enhanced hardness based on the size of grains and the shape of crystallites [J. Musil, in: A. Cavaleiro, J.T.M. De Hosson (Eds.), Nanostructured Hard Coatings, Kluwer Academic/Plenum Publishers, New York, 2005, Chapter 10]. A development of mechanical properties of the Zr–Ni–N films with increasing pN2 is also discussed in detail.

ChemInform Abstract: MECHANOCHEMICAL CHANGES OF NEODYMIUM PHOSPHATES BY GRINDING

AbstractDurch die mechanochemische Behandlung wird hexagonales NdPO4‐O.5 H2O bereits bei Raumtemp. in das monokline NdPO4 übergeführt (bei thermischer Behandlung erst bei 600°C).

Mechanochemical Changes of Neodymium Phosphates by Grinding

Abstract The effect of mechanochemical treatment on some neodymium phosphates was investigated. It is worth noting that on mechanochemical treatment NdPO4·0.5H2O (hexagonal) is gradually transformed into NdPC4 (monoclinic) at room temperature, while thermal change of NdPO4·0.5H2O to NdPO4 (monoclinic) happens at above 600 °C. Condensed phosphates, meta- and ultraphosphates, easily turned to X-ray amorphous structure by grinding.