scholarly journals Dense zircon (ZrSiO4) ceramics by a simple milling-sintering route

2018 ◽  
Vol 50 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Matías Gauna ◽  
María Conconi ◽  
Gustavo Suarez ◽  
Esteban Aglietti ◽  
Nicolás Rendtorff
Keyword(s):  
Vickers Hardness ◽  
Milling Time ◽  
Sintering Temperature ◽  
Rietveld Method ◽  
Tetragonal Zirconia ◽  
Time Effect ◽  
X Ray Diffraction ◽  
Refractory Powder ◽  
X Ray ◽  
Sintering Additives

In this work, a simple milling sintering route (pressure less) to process dense zircon ceramics from fine (D50 0.8 ?m) zircon powders is explored. Particularly, the milling time effect (0-120 min) and the maximum sintering temperature (1400-1600?C) were studied. The sintering grade developed microstructure and Vickers hardness (Hv) were evaluated and correlated. The dissociation of silicate into (monoclinic and tetragonal) zirconia and silica was evaluated by X-ray diffraction followed by the Rietveld method; it was found to be below 10 wt% in all the studied ranges. The sintering was enhanced by the milling pretreatment. No sintering additives were incorporated. Dense zircon (porosity below 1%) ceramics were obtained by a simple milling-sintering route of this high refractory powder at 100-200?C below the sintering temperature used with conventional processing routes to obtain equivalent final properties. The Vickers hardness reached: 9.0 GPa.

Effect of Process on the Dielectric Properties of BaTiO3-Based X9R Ceramics

2014 ◽  
Vol 906 ◽  
pp. 18-24 ◽  
Author(s):  
Bao Lin Zhang ◽  
Bin Bin Zhang ◽  
Ning Ning Wang ◽  
Jing Ming Fei
Keyword(s):  
Particle Size ◽  
Dielectric Properties ◽  
Milling Time ◽  
Sintering Temperature ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Sintered Ceramic ◽  
X Ray ◽  
Particle Size Analyzer

The effect of milling time and sintering process on the dielectric properties of BaTiO3-based X9R ceramics was investigated. The characterization of the raw powders and the sintered ceramic was carried out by X-ray diffraction and scanning electron microscopy. The particle size distribution of the mixed powders was examined by Laser Particle Size Analyzer. The results shown that with the milling time extended, the Cruie Peak was depressed, or even disappeared. Moreover, with the rise of sintering temperature, the dielectric constant of the ceramics increased and the dielectric loss decreased gradually. Eventually, by milling for 11h and sintering at 1090°Cfor 2h, good dielectric properties were obtained, which were ε25°C≥ 2526, εr/εr25°C≤± 12% (–55~200°C), tanδ≤1.12% (25°C).

Structure of Carbonated Hydroxyapatite Based on Rietveld Method

2008 ◽  
Vol 368-372 ◽  
pp. 1187-1189
Author(s):  
Xu Ran ◽  
Jun Guo Ran ◽  
Li Gou ◽  
Ji Yong Chen ◽  
Jiao Min Luo
Keyword(s):  
Crystal Structure ◽  
Sintering Temperature ◽  
Rietveld Method ◽  
Rietveld Analysis ◽  
Structure Parameters ◽  
X Ray Diffraction ◽  
Carbonated Hydroxyapatite ◽  
X Ray ◽  
Quantitative Results ◽  
Distortion Index

The crystalline structures of B-type carbonated hydroxyapatite (CHA) powders sintered at 700, 900 and 1100°C, respectively, were studied by Rietveld analysis of powder X-ray diffraction (XRD) data. A series of structure parameters, including lattice parameters (a and c), bond length and the distortion index of PO4 tetrahedron (Dind) were calculated by Rietveld method to characterize the fine structure of CHA. The broadening effect of XRD reflections was separated to calculate the micro-strain and crystalline size. The results showed that CHA become more stable with the increase of sintering temperature, but the CO3 2- is almost lost at temperature of 1100°C. The quantitative results about crystal structure of CHA based on crystalline structure simulated by Rietveld method are obtained.

XRD Analysis of Al-6vol%SnPb Composites Fabricated by Cold Forging Process with Various Sintering Temperatures

2015 ◽  
Vol 1087 ◽  
pp. 420-423
Author(s):  
Marwan Zakaria ◽  
Siti Rodiah Karim ◽  
Nur Azam Badarulzaman
Keyword(s):  
Vickers Hardness ◽  
Constant Pressure ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Xrd Analysis ◽  
Cold Forging ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optimum Result ◽  
Forging Process

This paper focused on fabrication of Al-6vol%SnPb from recycled Aluminium and recycled solder and its characterization in different sintering temperature. Al-20SnPb was fabricated by using cold forging process of flakes chip raw materials. Constant pressure (56.4 MPa) was used to implement cold forging process. Various sintering temperature (200 0C, 250 0C, 300 0C and 3500C) was studied to obtain the optimum hardness properties. The diffraction pattern of X-Ray diffraction (XRD) reveals the influence of varying sintering temperature of Al-6vol%SnPb. Vickers hardness result also support that, optimum result obtained is at sintering temperature 300 °C.

scholarly journals The Influence of Surface Preparation, Chewing Simulation, and Thermal Cycling on the Phase Composition of Dental Zirconia

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2133
Author(s):  
Markus Wertz ◽  
Florian Fuchs ◽  
Hieronymus Hoelzig ◽  
Julia Maria Wertz ◽  
Gert Kloess ◽  
...  
Keyword(s):  
Phase Composition ◽  
Rietveld Method ◽  
Tetragonal Zirconia ◽  
Surface Preparation ◽  
Dental Restoration ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chewing Simulation ◽  
Yttria Content ◽  
Dental Restorative

The effect of dental technical tools on the phase composition and roughness of 3/4/5 yttria-stabilized tetragonal zirconia polycrystalline (3y-/4y-/5y-TZP) for application in prosthetic dentistry was investigated. Additionally, the X-ray diffraction methods of Garvie-Nicholson and Rietveld were compared in a dental restoration context. Seven plates from two manufacturers, each fabricated from commercially available zirconia (3/4/5 mol%) for application as dental restorative material, were stressed by different dental technical tools used for grinding and polishing, as well as by chewing simulation and thermocycling. All specimens were examined via laser microscopy (surface roughness) and X-ray diffraction (DIN EN ISO 13356 and the Rietveld method). As a result, the monoclinic phase fraction was halved by grinding for the 3y-TZP and transformed entirely into one of the tetragonal phases by polishing/chewing for all specimens. The tetragonal phase t is preferred for an yttria content of 3 mol% and phase t″ for 5 mol%. Mechanical stress, such as polishing or grinding, does not trigger low-temperature degradation (LTD), but it fosters a phase transformation from monoclinic to tetragonal under certain conditions. This may increase the translucency and deteriorate the mechanical properties to some extent.

The Effect of Milling Time and Sintering Temperature on Synthesis of PbTiO3 by Mechanical Alloying

2015 ◽  
Vol 1123 ◽  
pp. 109-113
Author(s):  
Rindang Fajarin ◽  
Hariyati Purwaningsih ◽  
Febri Nugroho
Keyword(s):  
Mechanical Alloying ◽  
Room Temperature ◽  
Milling Time ◽  
Sintering Temperature ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Test Device ◽  
Test Analysis ◽  
X Ray ◽  
Multilayer Actuator

PbTiO3is one of electroceramic materials which can be applied for electronics and microelectronics due to their dielectric, pyroelectric, and piezoelectric properties. The members of PbTiO3-based ferroelectrics are widely used in multilayer, actuator and sensor capacitor. At room temperature, PbTiO3has a tetragonal perovskite structure. In this research, PbTiO3particles are synthesized by mechanical alloying method with variation of milling time and sintering temperature. The milling time variation is taken for 10, 20 and 30 hours. Sintering temperature variation is performed at 850, 900 and 1000°C. The powders used in the milling process are PbO and TiO2powders. X-Ray Diffraction (XRD) and Scanning Electron Microscopy–Electron Difraction X-ray (SEM-EDX) are performed to analyze the formation of PbTiO3phase. It is found that the synthesized powders contain 100% PbTiO3phase for all sintering temperatures. The PbTiO3particles have agglomeration shape with a broad particle size. The electrical properties of PbTiO3are measured using electrical test device. Electricity test analysis shows that the synthesized PbTiO3behaves as semiconductor-like.

scholarly journals Yttria stabilized tetragonal zirconia ceramics: preparation, characterization and applicationspplications

2018 ◽  
Vol 53 (2) ◽  
pp. 111-116 ◽  
Author(s):  
N Sultana ◽  
K Bilkis ◽  
R Azad ◽  
MR Qadir ◽  
MA Gafur ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Tetragonal Zirconia ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Zirconia Ceramics ◽  
X Ray ◽  
Hardness Tester ◽  
Maximum Value ◽  
Different Temperatures ◽  
Temperature Water

In this study, yttria stabilized tetragonal zirconia (YSTZ) ceramics were prepared and were sintered at different temperatures to find out the optimum sintering temperature for their better tetragonality and mechanical properties for their application as optical ferrule. Vicker’s hardness was performed by micro hardness tester and it was found to increase with the increase of sintering temperature to a maximum value, then it was decreased with higher sintering temperature. Water absorptivity and porosity were also seen to decrease as the densities of the specimens were increased. X-ray diffraction was employed to determine crystal structure of sintered samples. Surface morphology of the sintered samples was examined through field emission scanning electron microscope.Bangladesh J. Sci. Ind. Res.53(2), 111-116, 2018

Magnetic Properties and Hardness of Nanostructured WC-Co Cemented Carbide

2012 ◽  
Vol 727-728 ◽  
pp. 430-435
Author(s):  
J.B. Manuel ◽  
M.J. Diniz ◽  
Uílame Umbelino Gomes ◽  
Ariadne de Souza Silva ◽  
J.H. Araújo
Keyword(s):  
Magnetic Properties ◽  
Vickers Hardness ◽  
Milling Time ◽  
High Energy ◽  
Cemented Carbides ◽  
Time Increase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Fine Grain

Nacrystalline WC-10wt.%Co powders were prepared by high energy milling and liquid phase sintered. The powders with different milling time were characterized by X-ray diffraction and SEM. After sintered the WC-10wt.%Co cemented carbides exhibits ultra fine grain sizes. Coercitive field and Vickers hardness measurements on the consolided samples detected a significant increase and decrease Vickers hardness with the milling time increase in sintered samples.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

scholarly journals Synthesis and Na+ Ion Conductivity of Stoichiometric Na3Zr2Si2PO12 by Liquid-Phase Sintering with NaPO3 Glass

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3790
Author(s):  
Yongzheng Ji ◽  
Tsuyoshi Honma ◽  
Takayuki Komatsu
Keyword(s):  
Solid State ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Ion Conductivity ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Sintering Time ◽  
Lower Activation

Sodium super ionic conductor (NASICON)-type Na3Zr2Si2PO12 (NZSP) with the advantages of the high ionic conductivity, stability and safety is one of the most famous solid-state electrolytes. NZSP, however, requires the high sintering temperature about 1200 °C and long sintering time in the conventional solid-state reaction (SSR) method. In this study, the liquid-phase sintering (LPS) method was applied to synthesize NZSP with the use of NaPO3 glass with a low glass transition temperature of 292 °C. The formation of NZSP was confirmed by X-ray diffraction analyses in the samples obtained by the LPS method for the mixture of Na2ZrSi2O7, ZrO2, and NaPO3 glass. The sample sintered at 1000 °C for 10 h exhibited a higher Na+ ion conductivity of 1.81 mS/cm at 100 °C and a lower activation energy of 0.18 eV compared with the samples prepared by the SSR method. It is proposed that a new LPE method is effective for the synthesis of NZSP and the NaPO3 glass has a great contribution to the Na+ diffusion at the grain boundaries.

scholarly journals Transport and Dielectric Properties of Mechanosynthesized La2/3Cu3Ti4O12 Ceramics

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 313
Author(s):  
Mohamad M. Ahmad ◽  
Hicham Mahfoz Kotb ◽  
Celin Joseph ◽  
Shalendra Kumar ◽  
Adil Alshoaibi
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Boundary Conductivity ◽  
X Ray ◽  
Giant Dielectric ◽  
Mechanochemical Milling ◽  
Giant Dielectric Constant ◽  
Lower Temperature

La2/3Cu3Ti4O12 (LCTO) powder has been synthesized by the mechanochemical milling technique. The pelletized powder was conventionally sintered for 10 h at a temperature range of 975–1025 °C, which is a lower temperature process compared to the standard solid-state reaction. X-ray diffraction analysis revealed a cubic phase for the current LCTO ceramics. The grain size of the sintered ceramics was found to increase from 1.5 ± 0.5 to 2.3 ± 0.5 μm with an increase in sintering temperature from 975 to 1025 °C. The impedance results show that the grain conductivity is more than three orders of magnitude larger than the grain boundary conductivity for LCTO ceramics. All the samples showed a giant dielectric constant (1.7 × 103–3.4 × 103) and dielectric loss (0.09–0.17) at 300 K and 10 kHz. The giant dielectric constant of the current samples was attributed to the effect of internal barrier layer capacitances due to their electrically inhomogeneous structure.

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