Jesús Ma. Rincón

Characterization techniques of glasses and ceramics

1. Rare Earth Elements: Applications and Determination.- 2. Scanning Tunneling Microscopy: Applications to the Study of Ordered and Disordered Conducting Solid Surfaces.- 3. Basis and Applications of Convergent Beam Electron Diffraction (CBED) for the Investigation of Phases in Ceramics and Glass-Ceramics.- 4. Basis and Applications of High Resolution Electron Microscopy (HREM) for the Characterization of Ceramics and Glass-Ceramics.- 5. Applications of Differential Scanning Calorimetry for the Study of Transformation Processes in Quenched Alloys.- 6. Use of Thermal Analysis in Zeolite Research and Application.- 7. Viscous Flow of Glass Forming Liquids: Experimental Techniques for the High Viscosity Range.- 8. Diffusion Structural Analysis in the Characterization of Inorganic Materials.- 9. Texture Determination by Using X ray Diffraction.- 10. Recent Advances in X-Ray Fluorescence (XRF) Analysis.- 11. Mossbauer Spectroscopy Applied to Inorganic Materials.- 12. Neutron Diffraction in Amorphous Structures.

magnetic properties of glasses with high iron oxide content

A study of the magnetic properties of glasses with high iron oxide content has been carried out. This glass series was obtained by recycling goethite (FeOOH) industrial waste, with dolomite and glass cullet as complementary raw materials. The magnetisation as a function of applied magnetic field for these glasses was measured. According to the magnetic behaviour, which closely correlates with the iron content, these glasses can be classified as ferrimagnetic, superparamagnetic and paramagnetic. The magnetisation curves were analysed in terms of current models for these types of magnetic behaviour.

Indentation properties of ZrO2–SiO2 coatings on glass substrates

Abstract Sol–gel coatings of different composition in the ZrO 2 –SiO 2 system have been prepared, starting from several precursors (alkoxides and alkylalkoxides). Common soda lime silicate glass slides were used as substrates for coating deposition. The Vickers microhardness, H V , of the coated glass substrates have slightly higher values than that of uncoated glass. Young modulus, E , values for coated glass substrates are higher than that of uncoated glass. To compare the mechanical properties of the samples, the ratio H V / K IC (where K IC is the toughness) has been calculated and the concept of fragility discussed. The fragility of coated samples increases as the ZrO 2 content diminishes and the SiO 2 increases. Both scanning and transmission electron microscopy observations were performed to characterise the textural and microstructural properties of the coatings.

Mössbauer effect and x-ray distribution function analysis in complex Na2O-CaO-ZnO-Fe2O3-Al2O3-SiO2 glasses and glass-ceramics

Abstract Mossbauer spectroscopy at room temperature was carried out to determine the state of iron ions in complex glasses and glass-ceramics in the SiO 2 –CaO–ZnO–Na 2 O–Fe 2 O 3 –Al 2 O 3 system. Isomer shift values of the glasses suggest that Fe 3+ and Fe 2+ are in tetrahedral and octahedral coordination, respectively. The spectrum of the glass-ceramic shows that about 60 wt% total iron is in the magnetite phase. The Fe +3 /Fe +2 ratio varies with the total iron oxide content of the glasses, indicating that the vitreous network is more distorted when the iron content is greater. X-ray diffraction measurements were carried out to obtain the radial distribution function (RDF). The interatomic distances for Si–Si and Si–O have been determined. The complex composition of these glasses does not allow the estimation of Al–O and Fe–O distances.

Electron microscopy and EDX-microanalysis of photochromic silver halide glasses of the composition systems Al2O3-B2O3-SiO2 and Na2O-CaO-SiO2

The microstructure and microanalysis study of two glasses containing AgCl precipitated particles have been carried out by transmission electron microscopy (TEM, replica method), scanning electron microscopy (SEM) and SEM/EDX (energy dispersive X-ray spectrometry). The composition of these glasses doped with silver halide and CuO was formulated from the Al2O3-B2O3-SiO2 and Na2O-CaO-SiO2 systems respectively. In both glasses the seeds, nuclei, crystals and matrix were analysed, and the mean size and number of crystals were evaluated from the TEM and SEM observations. The microstructure in both glasses is different because of the different shape of the silver halide particles; the particles of the Al2O3-B2O3-SiO2 glass are rounded while Na2O-CaO-SiO2 shows square precipitated particles. Likewise, the darkening behaviour is basically different; the Al2O3-B2O3-SiO2 glass shows a higher darkening velocity than the Na2O-CaO-SiO2 glass, showing for this glass a very small slope value.

Optical properties of glasses in the ZnO–CdO–SiO 2 ternary system

The optical properties of new glasses in the ZnO-CdO-SiO(2) system containing high CdO levels (50-90 wt. %) has been determined. The refractive-index variation versus CdO and ZnO composition has been considered. Likewise, the refractive index and spectral transmittance in the 200-2600-nm range for these glasses has been carried out. From these optical measurements it can be stated that glasses in the ZnO-CdO-SiO(2) system would be adequate for infrared windows or as laser matrices.

Characterization of mullite/ZrO2 toughness ceramic materials microstructure by medium voltage analytical electron microscopy

Abstract A series of mullite/ZrO 2 and mullite/alumina/ZrO 2 high-toughness ceramic materials have been examined by analytical electron microscopy (AEM) at 300 kV and by using the following techniques: energy dispersive X-ray (EDX) microanalysis, microdiffraction and convergent beam electron diffraction (CBED). The relative advantages and disadvantages for the analysis at higher voltages on the investigation of advanced ceramics are compared with results obtained at 120 kV.