Search results for "Microscope"

Li2OSiO2Al2O3MeIIO Glass-Ceramic Systems for Tile Glaze Applications

1991

In order to verify the possibility of using glass-ceramic materials as tile coatings, the devitrification processes of three industrial formulations belonging to the Li2O─Al2O3─SiO2 glass-ceramic system were investigated by differential thermal analysis, X-ray diffractometry, scanning electron microscopy, and IR spectroscopy. Compositional variations were made by addition of large amounts of MgO or CaO or PbO (ZnO) oxides as well as through smaller additions of other oxides. In these systems the surface crystallization contributes appreciably to the bulk crystallization mechanism. All the systems investigated show a high tendency toward crystallization even at very high heating rates, devel…

Microstructural Evolution in Fast-Heated Cordierite-Based Glass-Ceramic Glazes for Ceramic Tile

2004

The crystallization mechanism of α-cordierite from a B 2 O 3 -and TiO 2 -containing glass submitted to fast heating in the cordierite primary phase field of the CaO-MgO-Al 2 O 3 -SiO 2 quaternary system was investigated. Addition of B 2 O 3 to a SiO 2 -rich glass suppressed the formation of μ-cordierite. This suppression facilitated densification by viscous flow before crystallization. Powder X-ray diffractometry, field-emission electron scanning microscopy, and energy-dispersive X-ray analysis revealed that α-cordierite nucleated directly from glass on the boundaries of original particles and was probably favored by TiO 2 , which acted as a nucleant. The growth kinetics of α-cordierite cry…

Effect of MgO/CaO ratio on the microstructure of cordierite-based glass-ceramic glazes for floor tiles

2005

Abstract The effect of the MgO/CaO ratio on the microstructure and microhardness of cordierite-based glass-ceramic glazes was studied. For this purpose glasses, with compositions in the cordierite primary phase field of the CaO–MgO–Al 2 O 3 –SiO 2 quaternary system and, with different MgO/CaO ratios, were prepared by melting. Glass powder pellets pressed under low pressure were fast heated at several temperatures simulating industrial floor-tile processing, and characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray emission spectroscopy (EDX). The studied glasses crystallized α-cordierite as the only crystalline phase…

Layer-by-Layer Graphene Growth on β-SiC/Si(001)

2019

ACS nano 13(1), 526 - 535 (2019). doi:10.1021/acsnano.8b07237

Atomic-resolution imaging of clean and hydrogen-terminated C(100)-(2×1)diamond surfaces using noncontact AFM

2010

Received 22 April 2010; published 14 May 2010High-purity, type IIa diamond is investigated by noncontact atomic force microscopy NC-AFM .Wepresent atomic-resolution images of both the electrically conducting hydrogen-terminated C 100 - 2 1 :Hsurface and the insulating C 100 - 2 1 surface. For the hydrogen-terminated surface, a nearly square unitcell is imaged. In contrast to previous scanning tunneling microscopy experiments, NC-AFM imaging allowsboth hydrogen atoms within the unit cell to be resolved individually, indicating a symmetric dimer alignment.Upon removing the surface hydrogen, the diamond sample becomes insulating. We present atomic-resolutionimages, revealing individual C-C dim…

Why are hydrogen ions best for MeV ion beam lithography?

2013

The exposure characteristics of poly-(methyl methacrylate) (PMMA) for 2MeV ^1H^+, 3MeV ^4He^2^+ and 6MeV ^1^2C^3^+ have been investigated. The samples were characterised using Atomic Force Microscopy (AFM), optical microscopy and Raman spectroscopy. Development was carried out using a 7:3 propan-2-ol:H"2O mixture to determine clearing and cross-linking fluences. It was found that protons had a considerably wider tolerance to exposure variations and a smaller span of doses within the ion track. Furthermore, the void formation and consequent stress-induced surface roughening were smaller for protons. For all ions, the C?C bond Raman signal increased continuously with dose and fluence, even we…

Multi-scale characterization of porosity in Boom Clay (HADES-level, Mol, Belgium) using a combination of X-ray μ-CT, 2D BIB-SEM and FIB-SEM tomography

2015

Abstract The Oligocene age Boom Clay is a potential host material for radioactive waste disposal in Belgium. To better understand the physical basis of transport mechanisms of radionuclides, we aim to characterize the pore space and its connectivity at nm-scale in 3D. In the present study, X-ray μ-CT and FIB-SEM (focused ion beam scanning electron microscopy) tomography were combined, to investigate the 3D pore space of a Boom Clay sample from the Mol-1 borehole (depth corresponding to the level of the HADES-URF – ‘high activity disposal experimental site underground research facility’) at the Mol–Dessel research site for radioactive waste disposal (Belgium). BIB-SEM (broad ion beam scannin…

2019

TEMPO-oxidized cellulose nanofibrils (TCNFs) have unique properties, which can be utilised in many application fields from printed electronics to packaging. Visual characterisation of TCNFs has been commonly performed using Scanning Electron Microscopy (SEM). However, a novel imaging technique, Helium Ion Microscopy (HIM), offers benefits over SEM, including higher resolution and the possibility of imaging non-conductive samples uncoated. HIM has not been widely utilized so far, and in this study the capability of HIM for imaging of TCNFs was evaluated. Freeze drying and critical point drying (CPD) techniques were applied to preserve the open fibril structure of the gel-like TCNFs. Both dry…

Evaluation of Silver Ion Bioavailability from Silver Doped Hydroxyapatite

2014

Thein vitrobehavior of silver doped hydroxyapatite (HAp/Ag) prepared by two wet precipitation routes were studied in water and simulated body fluid (SBF). In order to evaluate the silver ion bioavailability from HAp/Ag, the samples were soaked in SBF or water and kept at 37°C for fixed periods of time up to one year. After fixed periods of time, analyses of SBF and water solutions were performed and silver ion concentration within the solutions determined. According to silver release data from dense and porous HAp/Ag ceramic scaffolds, release rate of silver ions were reduced in water as the ion exchange there was slower compared to SBF solution. X-ray diffraction and scanning electron micr…

Charged colloidal model systems under confinement in slit geometry: a new setup for optical microscopic studies.

2013

A new experimental setup for optical microscopic studies of charged colloidal model systems under confinement between two flat walls is presented. The measurement cell consists of optically flat quartz substrates attached to piezo actuators. Those facilitate fast and flexible adjustment of the confining geometry. Optionally, the local cell height can be quantitatively controlled by in situ interferometric measurements. Proper choice of materials guarantees sufficient chemical inertia against contamination with salt ions. For efficient preparation of charged colloidal suspensions under strongly deionized conditions, the cell can be connected to a conventional pump circuit including a mixed b…