Improved densification by nano-sized sintering aids for Si3N4

1999 ◽  
Vol 14 (12) ◽  
pp. 4562-4569 ◽  
Author(s):  
Liwu Wang ◽  
Wolfgang M. Sigmund ◽  
Sukumar Roy ◽  
Fritz Aldinger
Keyword(s):  
Liquid Phase ◽  
Ball Milling ◽  
Combustion Process ◽  
Liquid Phase Sintering ◽  
Densification Process ◽  
Sintering Aids ◽  
X Ray Diffraction ◽  
X Ray

The densification of Si3N4 with nano-sized sintering aids that were in situ incorporated by a combustion process was studied in comparison with that of sintering aids mixed by ball milling. The combustion process directly produces amorphous and nano-sized Y–Al oxides within the Si3N4 powder. X-ray diffraction results indicate that amorphous Y–Al oxides begin to crystallize into Y3Al5O12 at about 600 °C. Additionally the nano-sized sintering aids are more homogeneously distributed and thereby promote the formation of eutectic melts at lower temperatures during liquid-phase sintering. Therefore, the densification process of Si3N4 during liquid-phase sintering is strongly accelerated. The microstructure of as-sintered parts from combusted powder seems more dense and homogeneous.

Preparation of Porous Nitinol Material by Hot-Isostatic Pressing

Materials ◽  
2005 ◽  
Author(s):  
Zhigang Xu ◽  
Cindy K. Waters ◽  
Gukan Rajaram ◽  
Jag Sankar
Keyword(s):  
Liquid Phase ◽  
Ball Milling ◽  
Energy Dispersive Spectroscopy ◽  
Hot Isostatic Pressing ◽  
Eutectic Point ◽  
Liquid Phase Sintering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isostatic Pressing ◽  
Preliminary Study

In this preliminary study, porous nitinol is fabricated using elemental Ni and Ti powders. The elemental powders were mixed at the ratio of 50:50 at.% by ball milling in preparation for pressing and sintering. The compacts were obtained by uniaxial pressing with a steel die of 12.5mm diameter. They were then subjected to hot isostatic pressing (HIPing) in an argon environment. The sintering pressure, temperature and time were varied in order to acquire porous nitinol. Porosity as high as 47.3% was achieved, which was benefited by partial liquid phase sintering. X-ray diffraction and energy dispersive spectroscopy (EDS) demonstrated that diffusion in the samples sintered at the temperature higher than the eutectic point was nearly complete, while the diffusion will take much longer time to complete at temperature lower that the eutectic point.

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.

Effect of WC Addition on Phase Formation and Microstructure of TiC-Ni Composites

2008 ◽  
Vol 55-57 ◽  
pp. 353-356
Author(s):  
Nawarat Wora-uaychai ◽  
Nuchthana Poolthong ◽  
Ruangdaj Tongsri
Keyword(s):  
Liquid Phase ◽  
Tungsten Carbide ◽  
Phase Formation ◽  
Liquid Phase Sintering ◽  
Precipitation Process ◽  
Solid Solution Phase ◽  
Binder Phase ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray

In this research, titanium carbide-nickel (TiC-Ni) composites, with tungsten carbide addition, were fabricated by using a powder metallurgy technique. The TiC-Ni mixtures containing between 0-15 wt. % tungsten carbide (WC), were compacted and then sintered at 1300°C and 1400°C, respectively. The phase formation and microstructure of the WC-added TiC-Ni composites have been investigated by X-ray diffraction and scanning electron microscopy techniques. Mechanical properties of these composites were assessed by an indentation technique. The X-ray diffraction patterns showed no evidence of tungsten rich phases in the sintered WC-added cermets. This indicates that during the sintering process, tungsten carbide particles were dissolved in metallic binder phase (Ni phase) via dissolution/re-precipitation process during liquid phase sintering. The liquid phase formed during sintering process could improve sinterability of TiC-based cermets i.e., it could lower sintering temperatures. The TiC-Ni composites typically exhibited a core-rim structure. The cores consisted of undissolved TiC particles enveloped by rims of (Ti, W)C solid solution phase. Hardness of TiC-Ni composites increased with WC content. Sintering temperature also had a slight effect on hardness values.

Phase Transformations in the Brazing Joint during Transient Liquid Phase Bonding of a γ-TiAl Alloy Studied with In Situ High-Energy X-Ray Diffraction

2018 ◽  
Vol 941 ◽  
pp. 943-948
Author(s):  
Katja Hauschildt ◽  
Andreas Stark ◽  
Hilmar Burmester ◽  
Ursula Tietze ◽  
Norbert Schell ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Materials Science ◽  
Transient Liquid Phase ◽  
High Energy ◽  
Transient Liquid Phase Bonding ◽  
X Ray Diffraction ◽  
Energy Materials ◽  
Joint Region ◽  
X Ray

TiAl alloys are increasingly used as a lightweight material, for example in aero engines, which also leads to the requirement for suitable repair techniques. Transient liquid phase bonding is a promising method for the closure of cracks (in non-critical or non-highly loaded areas). The brazing solder Ti-24Ni was investigated for brazing the alloy Ti-45Al-5Nb-0.2B-0.2C (in at. %). After brazing, the joint exhibits different microstructures and phase compositions. The transient liquid phase bonding process was investigated in the middle of the joint region in situ to acquire time resolved information of the phases, their development, and thus the brazing process. These investigations were performed using high-energy X-ray diffraction at the “High-Energy Materials Science” beamline HEMS, located at the synchrotron radiation facility PETRA III at DESY in Hamburg, Germany. For this, we used an induction furnace, which is briefly described here. During the analysis of the diffraction data with Rietveld refinement, the amount of liquid was refined with Gaussian peaks and thus could be quantified. Furthermore, while brazing four different phases occurred in the middle of the joint region over time. Additionally, the degree of ordering of the βo phase was determined with two ideal stoichiometric phases (completely ordered and disordered). Altogether, the phase composition changed clearly over the first six hours of the brazing process.

Microstructure and Properties of In Situ Fabricated Al-5wt.%Si-Al2O3 Composites

2012 ◽  
Vol 567 ◽  
pp. 15-20 ◽  
Author(s):  
Ling Cheng ◽  
De Gui Zhu ◽  
Ying Gao ◽  
Wei Li ◽  
Bo Wang
Keyword(s):  
Shear Strength ◽  
Liquid Phase ◽  
Solid Phase ◽  
Hold Time ◽  
Aluminum Matrix ◽  
Liquid Phase Sintering ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
X Ray

Alumina reinforced aluminum matrix composites (Al-5wt.%Si-Al2O3) fabricated by powder metallurgy through hot isotactic pressing were sintered in different processes, i.e. solid and liquid phase sintering. Optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-ray (EDX) techniques were used to characterize the sintered composites. The effects of solid phase and liquid phase sintering on density, microstructure, microhardness, compression and shear strength were investigated. It was found that in situ chemical reaction was completed in solid phase sintering, but the composites had lower microhardness, comprehension and shear strength due to low density and segregation of alumina and Si particles in microstructure. Segregation of reinforcement particles in solid phase sintering resulted from character of solid reaction and Si diffusion at high temperature over a long hold time.

In situ synchrotron X-ray diffraction studies of hydrogen desorption and absorption properties of Mg and Mg–Mm–Ni after reactive ball milling in hydrogen

2009 ◽  
Vol 57 (13) ◽  
pp. 3989-4000 ◽  
Author(s):  
R.V. Denys ◽  
A.B. Riabov ◽  
J.P. Maehlen ◽  
M.V. Lototsky ◽  
J.K. Solberg ◽  
...  
Keyword(s):  
Ball Milling ◽  
Hydrogen Desorption ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
X Ray ◽  
Milling In Hydrogen

High Tc Superconductor Films Grown by the Liquid Phase Epitaxial Technique

1989 ◽  
Vol 169 ◽  
Author(s):  
C. S. Yang ◽  
A. S. Yue
Keyword(s):  
Liquid Phase ◽  
Cross Sections ◽  
X Ray Diffraction ◽  
High Tc ◽  
Liquid Phase Epitaxial ◽  
X Ray ◽  
Diffraction Patterns ◽  
High Degree ◽  
Superconductor Films

AbstractHigh Tc superconducting YBa2Cu3O7 films have been prepared by the Liquid Phase Epitaxial (LPE) technique. The x‐ray diffraction patterns displayed a high degree of (00l) preferred orientations with c‐axes perpendicular to the film surfaces. The in‐situ grown YBa2Cu3O7 films showed zero‐resistivity at 76*K. Examination of the film cross sections by SEM revealed a growth mechanism.

Effect of Li0.8Ca0.2F1.2 on Sintering and Microwave Dielectric Properties of (Mg0.95Zn0.05)(Ti0.8Sn0.2)O4 Ceramics

2013 ◽  
Vol 538 ◽  
pp. 266-269
Author(s):  
Guo Guang Yao ◽  
Hong Ma ◽  
Xiu Lao Tian
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Microwave Dielectric Properties ◽  
Liquid Phase Sintering ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric

The effects of Li0.8Ca0.2F1.2 doped on the sinterability, phase constitutions and microwave dielectric properties of (Mg0.95Zn0.05)2(Ti0.8Sn0.2)O4 (MZTS) ceramics were investigated. The crystal structure was analyzed using X-ray diffraction. With 3.0 wt% Li0.8Ca0.2F1.2 addition, the densification sintering of MZTS ceramics was significantly lowed from 1325 oC to 1150 oC due to the liquid phase sintering. Secondary phases CaTiO3 and MgO were formed by reaction between MZTS and CaF2. 3.0wt% Li0.8Ca0.2F1.2-doped MZTS ceramics at 1150 oC for 5 h exhibited dielectric properties: εr=13.4, Qxf=46 672.3 GHz (at 9.3 GHz).

Preparation and Dielectric Properties of Li2O Doped BaZr0.25Ti0.75O3 Ceramics

2011 ◽  
Vol 284-286 ◽  
pp. 1460-1465
Author(s):  
Di Chen ◽  
Xiang Yun Deng ◽  
Jian Bao Li ◽  
Li Ming Wang ◽  
Xin Zheng Wu ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
X Ray Diffraction ◽  
Sintering Aid ◽  
X Ray ◽  
Ceramic Process ◽  
Low Sintering Temperature

BaZr0.25Ti0.75O3(BZT) ceramics were prepared by conventional ceramic process at a relatively low sintering temperature and with an addition of Li2O as the liquid-phase sintering aid. X-ray diffraction characterized results showed that the main crystal phase of the samples with 1.0wt% Li2O additive sintered at 1050°C～1250°C for 4h presented perovskite structure. The dielectric properties of BZT ceramics have been investigated. The dielectric constant of 1.0wt% Li2O doped BZT sintered at 1150°C decreased, and the dielectric loss increased by 0.0012 compared with that of the pure BZT sintered at 1450°C.

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