THE STRUCTURE AND PROPERTIES OF PHOSPHATE GLASSES WITH TRANSITION METALS ELEMENTS

Dans ce travail on a déterminé la formation du verre et quelques propriétés des verres du système : Ba(PO3)-Y2O3(MoO3)-TiO2(Fe2O3). Utilisant l'analyse des spectres Raman on présente les données de la structure du système ci-dessus mentionné. On a constaté la présence des groupes structurels métaphosphates et orthophosphates ainsi que la présence des fragments cristallins, dans la matrice du verre, dans le cas du système Ba(PO3)2-Y2O3. Les propriétés électriques des verres : la résistance spécifique (ρv), l'angle de perte (tgδx), la permittivité diélectrique (εr), indiquent le caractère diélectrique des verres, qui contiennent Y2O3 et une semi-conduction prononcée pour les verres à contenu Fe2O3 élevé.Conditions of melting glasses of the Ba(PO3)2 - Y2O3(MoO3) - TiO2 (Fe2O3) system and some of the properties of the glasses are discussed. Analysis of the Raman spectra was the source of information on the structure of the glasses. In the glass matrix of the Ba(PO3)2 - Y2O3 system were found structural metaphosphate and orthophosphate groups and crystal fragments. Electric properties : specific resistance (ρv), loss angle (tgδx) and permittivity (εr) indicated, the dielectric character for the glasses with Y2O3 and a highly semiconducting character for those with a greater content of Fe2O3

Modification of Ceo/CTo+Pd film structure under electric field influence during electron emission

We investigated the modification of structure of Ceo/Cyo+Pd films during cold electron emission from these films. Films were obtained by vacuum thermal deposition from two sources and were characterised before and after electron emission measurements by transmission electron microscopy and electron diffraction. Films were composed of nanocrystalline Pd objects dispersed in carbon/fullerenes matrix. I-V characteristics for electron emission were obtained in diode geometry with additionally applied voltage along the film surface. The modification of film structure occurred under applied electric field and the grouping of Pd nanocrystals into bigger objects was observed

Modification of Ceo/CTo+Pd film structure under electric field influence during electron emission

We investigated the modification of structure of Ceo/Cyo+Pd films during cold electron emission from these films. Films were obtained by vacuum thermal deposition from two sources and were characterised before and after electron emission measurements by transmission electron microscopy and electron diffraction. Films were composed of nanocrystalline Pd objects dispersed in carbon/fullerenes matrix. I-V characteristics for electron emission were obtained in diode geometry with additionally applied voltage along the film surface. The modification of film structure occurred under applied electric field and the grouping of Pd nanocrystals into bigger objects was observed

The Influence of Substrate on Size of Pd Nanoparticles in C-Pd Composites Obtained in the PVD and CVD Processes

This paper presents the results of research of C-Pd composite films obtained by the physical vapor deposition and chemical vapor deposition method. These films will be applied as hydrogen sensors. It has been examined whether the substrate has an impact on morphology and topologies of the C-Pd composite and whether the thermal conductivity of the substrate has an impact on the average size of the Pd nanoparticles. Substrates such as Al₂O₃, SiO₂, Si, and Mo were used, and in the physical vapor deposition process fullerene (C₆₀) and palladium acetate were deposited. Some of the samples were examined microscopically, while another part was modified in the chemical vapor deposition process in the presence of xylene. It was found that the average size of the Pd nanoparticles prepared in the physical vapor deposition process is independent of the substrate for all of the substrates used in the present experiment. During the chemical vapor deposition process an increase of the size of the Pd nanoparticles was observed - as expected. What is more, we noticed a weak relation between the size of the Pd nanoparticles and the type of substrate on which the C-Pd composite was deposited

Structural Studies of C-Ni-Pd Nanocomposite Films Deposited on Al₂O₃ Substrate

The properties of nanocomposite carbon-nickel-palladium (C-Ni-Pd) films deposited on Al₂O₃ substrate have been investigated and the results are presented in this work. C-Ni-Pd films were obtained by a 3 step process consisting of PVD/CVD/PVD methods. The structure and morphology of the obtained films were characterized by scanning electron microscopy and transmission electron microscopy techniques at various stages of film formation. Energy dispersive X-ray spectrometer was used for measuring the elements segregation in the obtained film. Transmission electron microscopy and scanning transmission electron microscopy observations have shown carbon nanotubes decorated with palladium nanoparticles in the final film. The average size of the palladium nanoparticles did not exceed 10 nm