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.

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.

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.

Preparation of HA-Zirconia Nanocomposite for Dental Applications

2013 ◽  
Vol 662 ◽  
pp. 35-39
Author(s):  
Kok Fong Lim ◽  
Muchtar Andanastuti ◽  
Rusnah Mustaffa ◽  
Chou Yong Tan
Keyword(s):  
Ball Milling ◽  
Cold Isostatic Pressing ◽  
Minimum Amount ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isostatic Pressing ◽  
Dental Applications

Hydroxyapatite (HA)-zirconia nanocomposite is synthesised by mixing as-synthesised HA with commercially available yttria-stabilised zirconia nanopowder using wet ball milling. The sample is consolidated using uniaxial pressing followed by cold isostatic pressing. The composites containing 0 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, and 5 wt% zirconia are prepared and sintered at 1100, 1200, and 1300 °C. Results from the X-ray diffraction (XRD) and density analyses show that the proposed approach produced a highly dense sample (>98.8%) with minimum amount of impurity, which is suitable for dental applications.

Rapid synthesis of bulk Ti2AlC by self-propagating high temperature combustion synthesis with a pseudo–hot isostatic pressing process

2009 ◽  
Vol 24 (8) ◽  
pp. 2528-2535 ◽  
Author(s):  
Yuelei Bai ◽  
Xiaodong He ◽  
Yibin Li ◽  
Chuncheng Zhu ◽  
Sam Zhang
Keyword(s):  
High Temperature ◽  
Combustion Synthesis ◽  
Hot Isostatic Pressing ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
X Ray ◽  
Isostatic Pressing ◽  
Pressing Process ◽  
Temperature Combustion ◽  
High Temperature Combustion

In this study, the dense polycrystalline Ti2AlC was synthesized by self-propagating high-temperature combustion synthesis with the pseudo–hot isostatic pressing process (SHS/PHIP). The resultant phase purity is highly dependent on the mol ratio of raw powders. The Ti2AlC was densified by applying pressure after the SHS reaction. The resultant sample mainly contains typical plate-like nonstoichiometric Ti2AlCx (x = 0.69) with grain size of ∼6 µm. The sample shows the Vickers hardness of 5.5 GPa, highest flexural strength of 431 MPa, compressive strength of 1033 MPa, and fracture toughness of 6.5 MPa·m1/2. No indentation cracks in Ti2AlCx were observed, indicative of a damage material nature. The reaction mechanism for the formation of SHS/PHIP-derived Ti2AlC is also discussed based on differential thermal analysis and x-ray diffraction results.

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).

Formation of Superconducting La2−xSrxCaCu2O6−δ Ceramic with Application of O2-HIP Technique

1991 ◽  
Vol 251 ◽  
Author(s):  
Kiyoshi Oshima ◽  
Yuichi Watanabe ◽  
Masasuke Takata ◽  
Kozo Ishizaki
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Strong Correlation ◽  
Hot Isostatic Pressing ◽  
Lattice Parameters ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isostatic Pressing ◽  
Diffraction Patterns

ABSTRACTSuperconducting La2−xSrxCaCu2O6−δ ceramics (x=0−0.6) were prepared with application of the oxygen-hot-isostatic pressing (O2-HIP) technique. The Tc of various samples was found to depend on both the Sr content and the applied oxygen partial pressure in the HIP treatment. The maximum Tc onset of 50K was observed for samples of the composition x=0.3 and 0.4 HIPped at 1050°C under 60atm oxygen partial pressure, and x=0.1 and 0.2 HIPped at 1050°C under 400atm oxygen partial pressure, respectively. From the analysis of x-ray diffraction patterns for superconducting substances, it was found that there existed a strong correlation between superconducting properties and the lattice parameters.

Thermal Conversion of Cs-exchanged IONSIV IE-911 into a Novel Caesium Ceramic Wasteform by Hot Isostatic Pressing

2013 ◽  
Vol 1518 ◽  
pp. 67-72 ◽  
Author(s):  
Tzu-Yu Chen ◽  
Joseph A. Hriljac ◽  
Amy S. Gandy ◽  
Martin C. Stennett ◽  
Neil C. Hyatt ◽  
...  
Keyword(s):  
Diffraction Data ◽  
Hot Isostatic Pressing ◽  
Rietveld Analysis ◽  
Thermal Conversion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isostatic Pressing ◽  
B Method ◽  
Mass Fractions

ABSTRACTHot Isostatic Pressing of Cs-exchanged IONSIV IE-911 samples is shown to produce a mixture of ceramic phases, the nature and mass fractions of these have been determined by Rietveld analysis of powder X-ray diffraction data. The main Cs phase that forms is Cs2TiNb6O18, after this reaches approximately 30% of the total crystalline content the remaining Cs is partitioned into Cs2ZrSi6O15. Durability tests using the PCT-B method for 7 days at 90 °C with deionised water lead to Cs leach rates of 0.032 and 0.038 g∙m−2∙day−1 for samples exchanged to 6 and 12 wt% Cs, respectively, indicating a durable wasteform is produced.

Sintering of Titanium Powder Compacts for Containerless Hot Isostatic Pressing

2009 ◽  
Vol 618-619 ◽  
pp. 509-512 ◽  
Author(s):  
Ray J. Low ◽  
Ian M. Robertson ◽  
Ma Qian ◽  
Graham B. Schaffer
Keyword(s):  
Liquid Phase ◽  
Titanium Powder ◽  
Hot Isostatic Pressing ◽  
Cost Effective ◽  
Liquid Phase Sintering ◽  
Full Density ◽  
Isostatic Pressing ◽  
Surface Densification ◽  
Powder Compacts ◽  
Made In

The liquid-phase sintering of Ti-Si binary alloys using mixed elemental powders has been explored. Sintering at low liquid contents avoids excessive porosity and bulging of compacts, and leads to development of a densified surface. Compacts made in this way can be HIPped without a container to full or near full densities. Exploiting the surface densification phenomenon may enable cost-effective net shape manufacturing of full density titanium components.

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