scholarly journals Surface Characterization and Conductivity of Two Types of Lithium-Based Glass Ceramics after Accelerating Ageing

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5632
Author(s):  
Marko Jakovac ◽  
Teodoro Klaser ◽  
Borna Radatović ◽  
Željko Skoko ◽  
Luka Pavić ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Glass Ceramics ◽  
Structural Defects ◽  
Lithium Silicate ◽  
Dental Ceramics ◽  
Ion Diffusion ◽  
X Ray ◽  
The Impact ◽  
Non Destructive ◽  
Scanning Electron

In this study, two different dental ceramics, based on zirconia-reinforced lithium-silicate (LS1) glass-ceramics (Celtra Duo, Dentsply Sirona, Bensheim, Germany) and lithium disilicate (LS2) ceramics (IPS e.max CAD, Ivoclar, Vivadent, Schaan, Liechtenstein) were examined. They were tested prior to and after the crystallization by sintering in the dental furnace. Additionally, the impact of ageing on ceramic degradability was investigated by immersing it in 4% acetic acid at 80 °C for 16 h. The degradability of the materials was monitored by Impedance Spectroscopy (IS), X-Ray Powder Diffraction (XRPD), and Field Emission Scanning Electron Microscope (FE-SEM) techniques. It was detected that LS2 (vs. LS1) samples had a lower conductivity, which can be explained by reduced portions of structural defects. XRPD analyses also showed that the ageing increased the portion of defects in ceramics, which facilitated the ion diffusion and degradation of samples. To summarize, this study suggests that the non-destructive IS technique can be employed to probe the ageing properties of the investigated LS1 and LS2 ceramics materials.

scholarly journals Methods of the Detection and Identification of Structural Defects in Saturated Metallic Composite Castings

2017 ◽  
Vol 17 (3) ◽  
pp. 37-44 ◽  
Author(s):  
K. Gawdzińska
Keyword(s):  
Electron Microscopy ◽  
Complex Structure ◽  
Gravimetric Method ◽  
Structural Defects ◽  
X Ray ◽  
Metallic Composite ◽  
Detection And Identification ◽  
Metallic Composites ◽  
Non Destructive ◽  
Scanning Electron

Abstract Diagnostics of composite castings, due to their complex structure, requires that their characteristics are tested by an appropriate description method. Any deviation from the specific characteristic will be regarded as a material defect. The detection of defects in composite castings sometimes is not sufficient and the defects have to be identified. This study classifies defects found in the structures of saturated metallic composite castings and indicates those stages of the process where such defects are likely to be formed. Not only does the author determine the causes of structural defects, describe methods of their detection and identification, but also proposes a schematic procedure to be followed during detection and identification of structural defects of castings made from saturated reinforcement metallic composites. Alloys examination was conducted after technological process, while using destructive (macroscopic tests, light and scanning electron microscopy) and non-destructive (ultrasonic and X-ray defectoscopy, tomography, gravimetric method) methods. Research presented in this article are part of author’s work on castings quality.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Effect of Dip-Coating Cycle on Some Physical Properties of Cu2NiSnS4 Thin Films for Photovoltaic Applications

2021 ◽  
Author(s):  
Ahmed ZITI ◽  
Bouchaib HARTITI ◽  
Amine BELAFHAILI ◽  
Hicham LABRIM ◽  
Salah FADILI ◽  
...  
Keyword(s):  
Thin Films ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sol Gel ◽  
Dip Coating ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Uv Visible ◽  
The Impact ◽  
Scanning Electron

Abstract Quaternary semiconductor Cu2NiSnS4 thin film was made by the sol-gel method associated to dip-coating technique on ordinary glass substrates. In this paper, we have studied the impact of dip-coating cycle at different cycles: 4, 5 and 6 on the structural, compositional, morphological, optical and electrical characteristics. CNTS thin films have been analyzed by various characterization techniques including: X-ray diffractometer (XRD), Raman measurements, scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDS), UV-visible spectroscopy and four-point probe method. XRD spectra demonstrated the formation of cubic Cu2NiSnS4 with privileged orientation at (111) plane. Crystallite size of cubic CNTS thin films increase with from 6.30 to 9.52 with dip-coating cycle augmented. Raman scattering confirmed the existence of CNTS thin films by Raman vibrational mode positioned at 332 cm− 1. EDS investigations showed near-stoichiometry of CNTS sample deposited at 5 cycles. Scanning electron microscope showed uniform surface morphologies without any crack. UV-visible spectroscopy indicated that the optical absorption values are larger than 104 cm− 1, Estimated band gap energy of CNTS absorber layers decrease from 1.64 to 1.5 eV with dip-coating cycle increased. The electrical conductivity of CNTS thin films increase from 0.19 to 4.16 (Ω cm)-1. These characteristics are suitable for solar cells applications.

Study of the Potentiality of Residue from Kaolin Industry as Ceramic Raw Material to Produce Porcelanate Gres

2005 ◽  
Vol 498-499 ◽  
pp. 420-424
Author(s):  
M.A.F. Ramalho ◽  
Lisiane Navarro de Lima Santana ◽  
Gelmires Araújo Neves ◽  
Hélio Lucena Lira
Keyword(s):  
Public Health ◽  
Physical And Mechanical Properties ◽  
Mechanical Tests ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Public ◽  
The World ◽  
The Impact ◽  
Scanning Electron

The recycling of industrial residues has being intensified all over the world, mainly due to the increase of the impact to the environment, and the growing volume of solid residues that put in risk the public health and degrade the natural resources. So, the aim of this work is to study the potentiality of the residue from kaolin industry, as ceramic raw material to produce porcelanate gres. A composition was formulated, mixed and forming by pressing (from 30 MPa to 50 MPa). After, it was sinterized at temperatures of 1180°C, 1200°C, 1220°C and 1240°C. The samples were submitted to physical and mechanical tests and characterized by X-ray diffraction and scanning electron microscopy. The preliminary results from physical and mechanical properties showed that the residue can be used to produce porcelanate gres according to Brasilian Norms (NBR 13818), at temperatures of 1220°C and 1240°C.

Influences of Fe2O3 Doping on the Crystallization of SiO2-Al2O3-MgO-K2O-ZrO2-F Glass-Ceramics

2009 ◽  
Vol 79-82 ◽  
pp. 1503-1506 ◽  
Author(s):  
Qing Bo Tian ◽  
Li Na Xu ◽  
Li Yang ◽  
Yan Sheng Yin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Elevated Temperatures ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Crystallization Peak ◽  
X Ray ◽  
Microstructural Morphology ◽  
Microscopy Techniques ◽  
Scanning Electron

The influences of Fe2O3 doping on crystallization characteristics and microstructural morphology in the SiO2-Al2O3-MgO-K2O-ZrO2-F glass were investigated by using differential scanning calorimeter, X-ray diffraction and scanning electron microscopy techniques. The results indicate that the addtions of Fe2O3 shift the crystallization peaks to higher temperatures and the crystallization peaks increases in magnitude and the gap values between two crystallization peak temperatures boarden with the increment of Fe2O3 contents.The star-shaped crystals of cordietite by dendritic-manner growths are homogeneously precipitated in the rusidual glass. The mica phases, which are precipitated at interdendritic cordietite phases and formed the plate shapes at the elevated temperatures. The mica crystals grow at the expense of cordietite phases and finally form the composites of mica/cordietite uniformly distributed.

Gel-derived amorphous cesium-aluminosilicate powders useful for formation of pollucite glass-ceramics

1991 ◽  
Vol 6 (2) ◽  
pp. 217-219 ◽  
Author(s):  
Mari A. Hogan ◽  
Subhash H. Risbud
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Amorphous Powder ◽  
Glass Crystallization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Powders ◽  
Gel Processing ◽  
Scanning Electron

Amorphous powders in the Cs2O–Al2O3−SiO2 system were prepared by sol-gel processing. Gels made from TEOS, Al-chelate, and Cs-acetate were dried and calcined to obtain molecularly mixed powders of analyzed compositions in the range useful for conversion to pollucite (CsAlSi2O6) glass-ceramics. X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetry (TG), and scanning electron microscopy (SEM) were used to characterize the powders. A typical amorphous powder of analyzed chemical composition (in wt.%) = 28.05Cs2O, 37.77SiO2, and 37.96Al2O3 was found to have a glass transition temperature of 945 °C and a glass crystallization temperature of 1026 °C. Preliminary experimental results of densification and crystallization of the amorphous powders show pollucite/mullite phases to be present.

Investigation of Structural Defects in 4H SiC Wafers

1994 ◽  
Vol 339 ◽  
Author(s):  
M. Tuominen ◽  
R. Yakimova ◽  
R. C. Glass ◽  
T. Tuomi ◽  
E. Janzén
Keyword(s):  
Electron Microscopy ◽  
Structural Defects ◽  
Semiconductor Materials ◽  
Power Device ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Device Applications ◽  
Scanning Electron

ABSTRACTFor high-power device applications SiC has better physical and electronic properties than the traditional semiconductor materials Si and GaAs. In this work, structural defects of 4H SiC wafers have been studied and partly compared with results from a previous study of 6H material. Optical microscopy, scanning electron microscopy, high-resolution X-ray diffraction and synchrotron X-ray topography were used for structural studies of 4H SiC.Optical micrographs show micropipes and larger specific defects - tubes and cracks. X-ray rocking curve peaks are broad and split revealing the mosaicity of the material. Synchrotron X-ray topographs show areas having a large number of defects, images of cracks and micropipes, and misorientated regions close to the micropipes.

Fabrication and Characterization of a Feldspar-Alumina for Dental Ceramic

2010 ◽  
Vol 160-162 ◽  
pp. 424-427
Author(s):  
Guang Lei Zhang ◽  
Guo Qiang Qin ◽  
Yuan Hua Zhang ◽  
Pu Cheng ◽  
Chang Tao Shao
Keyword(s):  
Sinter Temperature ◽  
Bending Strength ◽  
Dental Ceramics ◽  
Alumina Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fabrication And Characterization ◽  
Sintering Method ◽  
Scanning Electron

Feldspar-alumina dental ceramics were produced by impressed sintering method and characterized by X-ray diffraction and scanning electron microscope techniques. The machinability of the obtained alumina ceramics was evaluated by grinding capacity in the simulative grinding experiment. The results show that an appropriate amount of feldspar additive can reduce the sinter temperature and improve density, bending strength and machinability of alumina dental ceramics. Under 10 wt% feldspar and 1450 °C sinter temperature, the relative density and bending strength of ceramic reached 93.62% and 235MPa, respectively.

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