A hydrothermal hot-pressing method: apparatus and application

Yamasaki, Nakamichi; Yanagisawa, Kazumichi; Nishioka, Mamoru; KANAHARA, Satoshi

doi:10.1007/978-94-009-0743-0_70

Cited by 26 publications

(34 citation statements)

References 4 publications

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“…6a). Likewise, a multimodal PSD curve was determined for the MgHA4 (1.5 m particle size) green pellet, which had large pore size interval ( [25,29]. These results agree with the apparent density variation of the MgHA pellets ( Fig.…”

Section: Packing Mechanism Of Mgha Powders Under Hhp Conditionssupporting

confidence: 82%

“…The moistened powder was then placed in a cylindrical autoclave chamber (20 mm in diameter), which is used in conventional HHP, which is described in ref. [29]. The HHP autoclave was subsequently loaded at a constant pressure of 60 MPa, and this pressure was continuously applied during the heating, compaction time and cooling-down stages.…”

Section: Densification Of Mgha Powders Under Hhp Conditionsmentioning

confidence: 99%

“…A water content above 15 wt% caused moisture leakage from the pellet during the heating and compaction stages. The leaked moisture migrated to the inner piston reservoir volume and was then condensed during the cooling stage of the HHP treatment [29]. This excess water content did not react with the MgHA particles and therefore had a limited contribution to the densification process of the powders.…”

Section: Low-temperature Densification Of Mgha Powders By Hhpmentioning

confidence: 99%

“…In general, the vast research work conducted last two decades on the HAp low-temperature powder densification. It has been based on the hydrothermal reaction kinetics principals and mechanisms [37][38][39], which were determined for various inorganic [40][41][42][43][44] and organic [45] powders at temperatures in the range of 100 -300 ºC that reacted with water and alkaline medium under HHP conditions. Likewise, a new technology for sintering ceramic materials named as hydrothermal-assisted cold sintering process has recently been proposed, which involves hydrothermal reaction fundamentals in a broad variety of aqueous solutions [46].…”

Section: Microstructural Aspects and Mechanical Strength Of Mgha Compmentioning

confidence: 99%

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Low-temperature densification of Mg-doped hydroxyapatite fine powders under hydrothermal hot processing conditions

Montoya-Cisneros

Rendón-Ángeles

Matamoros-Veloza

et al. 2017

Ceramics International

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Abstract:Densification of calcium hydroxyapatite fine powders doped with different concentrations of Mg (2, 4 and 6 mol % Mg, MgHA) was successfully achieved for the first time in a nearly fully dense state using the 2 hydrothermal hot pressing (HHP) technique at low temperatures. Consolidation of MgHA powders was studied under different temperatures (150-240 ºC), reaction times (1-6 h), and powder particle size (20 nm-1.5 m). X-Ray diffraction analyses indicated that the particle densification under HHP conditions proceeded without any variation in the crystalline structure and regardless of the Mg content. The results from this work showed that an increase in temperature accelerates the reaction between MgHA particles and water (solvent) mixed during the hydrothermal treatment. Particle packing associated with bulk densification was achieved through a massive dissolution-recrystallisation mechanism, which induced the formation of small particles that rapidly crystallised on the surface of the partially dissolved original MgHA particles. The optimum conditions to obtain pellets with a high apparent density of 3.0758 ± 0.001 g/cm 3 and tensile strength value of 12.6 ± 0.6 MPa were 10 wt% of water at a temperature of 240 ºC with a 6 h reaction time and 6 mol % of Mg (MgHA3). The use of the HHP technique coupled with the fine particle size and reactivity of the MgHA precursor powders with water allowed us to produce disks that were compacted to a nearly full dense state with a low content of open porosity of 2.0 %.

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Section: Packing Mechanism Of Mgha Powders Under Hhp Conditionssupporting

confidence: 82%

Section: Densification Of Mgha Powders Under Hhp Conditionsmentioning

confidence: 99%

Section: Low-temperature Densification Of Mgha Powders By Hhpmentioning

confidence: 99%

Section: Microstructural Aspects and Mechanical Strength Of Mgha Compmentioning

confidence: 99%

See 2 more Smart Citations

Low-temperature densification of Mg-doped hydroxyapatite fine powders under hydrothermal hot processing conditions

Montoya-Cisneros

Rendón-Ángeles

Matamoros-Veloza

et al. 2017

Ceramics International

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“…Developed in Japan, hydrothermal hot-pressing is based on an autoclave that is externally heated [7], the powder with a proper content of water being placed between two pistons, which transmit uniaxial pressure. The pistons have a space for the release of water included in the starting powder.…”

mentioning

confidence: 99%

Unveiling the mechanisms of cold sintering of ZnO at 250 °C by varying applied stress and characterizing grain boundaries by Kelvin Probe Force Microscopy

et al. 2018

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The sintering behavior of nanocrystalline ZnO was investigated at only 250 °C. Densification was achieved by the combined effect of uniaxial pressure and the addition of water both in a Field Assisted Sintering Technology/Spark Plasma Sintering apparatus and a warm hand press with a heater holder. The final pure ZnO materials present high densities (> 90 % theoretical density) with nano-grain sizes. By measuring the shrinkage rate as a function of applied stress it was possible to identify the stress exponent related to the densification process. A value larger than one points to non-linear relationship going beyond single solid-state diffusion or liquid phase sintering. Only a low amount of water (1.7 wt.%) was needed since the process is dictated by the adsorption on the surface of the ZnO particles. Part of the adsorbed water dissociates into H + and OH -ions, which diffuse into the ZnO crystal structure, generating grain boundaries/interfaces with high defect chemistry. As characterized by Kelvin Probe Force Microscopy, and supported by impedance spectroscopy, this highly defective grain boundary area presents much higher surface energy than the bulk. This highly defective grain boundary area with high potential reduces the activation energy of the atomic diffusion, leading to sinter the compound at low temperature.

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Solid‐State Li Ion Batteries with Oxide Solid Electrolytes: Progress and Perspective

Jiang

Cao

et al. 2023

Energy Tech

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Figure 5. a) Cross-section scanning electron microscopy (SEM) of Li|LMF@LLZTO interface and the corresponding partial enlarged view. Reproduced with permission. [98] Copyright 2022, Elsevier. b) The molten Li-C composite on LLZTO pellet. Reproduced with permission. [100] Copyright 2019, Wiley-VCH. c) The Nb-modified LLZO/LiCoO 2 interface suppresses the mutual diffusion and produces a Li-conductive amorphous phase. Reproduced with permission. [106] Copyright 2014, Elsevier. d) The amorphous Ge coating between LAGP SSE and Li metal.

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A hydrothermal hot-pressing method: apparatus and application

Cited by 26 publications

References 4 publications

Low-temperature densification of Mg-doped hydroxyapatite fine powders under hydrothermal hot processing conditions

Low-temperature densification of Mg-doped hydroxyapatite fine powders under hydrothermal hot processing conditions

Unveiling the mechanisms of cold sintering of ZnO at 250 °C by varying applied stress and characterizing grain boundaries by Kelvin Probe Force Microscopy

Solid‐State Li Ion Batteries with Oxide Solid Electrolytes: Progress and Perspective

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