Abstract:High magnetostriction and coupling coefficient for sintered cobalt ferrite derived from superparamagnetic nanoparticles Appl. Phys. Lett. 101, 072405 (2012) Electrical and thermoelectric properties of single-wall carbon nanotube doped Bi2Te3 Appl. Phys. Lett. 101, 031909 (2012) The effect of Peltier heat during current activated densification Appl. Phys. Lett. 101, 013113 (2012) Studies of sintered MRE-Fe-B magnets by DyF3 addition or diffusion treatment (MRE=Nd+Y+Dy) J. Appl. Phys. 111, 07A736 (2012) Prope… Show more
“…In most cases, these approaches involved the diamond deposition on seeds. Recently, solvothermal diamond nucleation, growth, and sintering were proposed by Yamasaki and co-workers [30,31].…”
Section: Development Of New Solvothermal Processes For Preparing Funcmentioning
International audienceNitrides constitute an important class of materials due to their physical properties. In this way, all processes related to their synthesis or shaping are of relevant interest. A solvothermal process can be described as a reaction between precursors in a close system in the presence of a solvent and at a temperature higher than the boiling point of the solvent, with pressure being consequently involved. Depending on the pressure and temperature, the solvent is in sub- or supercritical conditions. The system precursors/solvent can be either homogeneous or heterogeneous. Concerning nitrides, solvothermal processes have been mainly developed in three domains: 1. the preparation of novel compositions / 2. the elaboration of nanocrystallites well defined in size and morphology / 3. the crystal-growth of functional nitrides such as GaN. Considering the synthesis of novel nitrides, different solvothermal reactions can be used versus the nitriding agent (N3- or N./GHPR_A_350185_O_XML_IMAGES/GHPR_A_350185_O_ILM0001.gif ) and the nature of the solvent (nitriding solvent or non-reactive solvent). Different examples will be given and the potentialities of solvothermal processes in the preparation of novel nitrides will be discussed
“…In most cases, these approaches involved the diamond deposition on seeds. Recently, solvothermal diamond nucleation, growth, and sintering were proposed by Yamasaki and co-workers [30,31].…”
Section: Development Of New Solvothermal Processes For Preparing Funcmentioning
International audienceNitrides constitute an important class of materials due to their physical properties. In this way, all processes related to their synthesis or shaping are of relevant interest. A solvothermal process can be described as a reaction between precursors in a close system in the presence of a solvent and at a temperature higher than the boiling point of the solvent, with pressure being consequently involved. Depending on the pressure and temperature, the solvent is in sub- or supercritical conditions. The system precursors/solvent can be either homogeneous or heterogeneous. Concerning nitrides, solvothermal processes have been mainly developed in three domains: 1. the preparation of novel compositions / 2. the elaboration of nanocrystallites well defined in size and morphology / 3. the crystal-growth of functional nitrides such as GaN. Considering the synthesis of novel nitrides, different solvothermal reactions can be used versus the nitriding agent (N3- or N./GHPR_A_350185_O_XML_IMAGES/GHPR_A_350185_O_ILM0001.gif ) and the nature of the solvent (nitriding solvent or non-reactive solvent). Different examples will be given and the potentialities of solvothermal processes in the preparation of novel nitrides will be discussed
“…The first one consists of mixing diamond seeds with different liquids such as 10 M NaOH, C-H-O rich, water, 1,1,1-tichlorethane, hexachlorocyclohexane or dichloromethane. These experiments were mostly performed in piston cylinder (1–2 GPa) ( Figure 7 a) or Roy-Tuttle autoclave (few hundred MPa) at temperatures up to 1450 °C (mostly to 300 °C) and for duration between 1 and 21 days, mostly 3 days [ 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ]. In all these studies, it is unclear if diamonds grow on seeds or not.…”
Section: On the Way To Catalyst-free/binderless Synthetic Diamondsmentioning
Nowadays, synthetic diamonds are easy to fabricate industrially, and a wide range of methods were developed during the last century. Among them, the high-pressure–high-temperature (HP–HT) process is the most used to prepare diamond compacts for cutting or drilling applications. However, these diamond compacts contain binder, limiting their mechanical and optical properties and their substantial uses. Binderless diamond compacts were synthesized more recently, and important developments were made to optimize the P–T conditions of sintering. Resulting sintered compacts had mechanical and optical properties at least equivalent to that of natural single crystal and higher than that of binder-containing sintered compacts, offering a huge potential market. However, pressure–temperature (P–T) conditions to sinter such bodies remain too high for an industrial transfer, making this the next challenge to be accomplished. This review gives an overview of natural diamond formation and the main experimental techniques that are used to synthesize and/or sinter diamond powders and compact objects. The focus of this review is the HP–HT process, especially for the synthesis and sintering of binderless diamonds. P–T conditions of the formation and exceptional properties of such objects are discussed and compared with classic binder-diamonds objects and with natural single-crystal diamonds. Finally, the question of an industrial transfer is asked and outlooks related to this are proposed.
“… Figure 3 Road map tracing milestones in near room temperature consolidation ( T < 300 °C) over the past four decades. Several techniques have been developed, based on dry (top) and wet (bottom) ULES [11-74]. …”
Section: Recent Developments In Near Room Temperature Consolidation: ...mentioning
confidence: 99%
“…Consolidation and crystallisation of amorphous titania by hydrothermal hot-pressing with a Vickers hardness 7.83 GPa was achieved at 350 °C (slightly above the typical temperature limit for ULES) under 200 MPa by Yanagisawa et al [47]. In 2006, Yokosawa et al [51] attempted HHP of diamond powder in the presence of a chlorinated hydrocarbon under a pressure of 1 GPa (their equipment was particularly advanced and was able to apply pressure up to 5 GPa). Raman spectroscopy of the sintered material detected only sp3 bonds, suggesting the formation of diamond to diamond bonding.…”
Section: Recent Developments In Near Room Temperature Consolidation: ...mentioning
The need to reduce the energy consumed and the carbon footprint generated by firing ceramics has stimulated research to develop consolidation techniques operating at lower temperatures, ideally not exceeding 300°C. This has been realised in Ultra Low Energy Sintering (ULES) using high pressure (hundreds of MPa) in the presence of a transient liquid phase, which accelerates plasticity, grain boundary/surface diffusion and mass transport. Several ULES techniques have been developed in the past 50 years, and a common feature of all of them is low temperature consolidation, through mechanisms not yet fully understood, enabling multi-material integration (e.g. organics and inorganics). This research could transform the traditional firing of functional and structural materials. Early stage work on ULES, started in the 1960s, clearly demonstrated cohesion between the compacted particles exceeding what was possible if simply produced by Van der Waals bonding, suggesting the formation of primary inter-particle bonds. Surprisingly, metals Cold Sintered (CS) in dry conditions at room temperature can be even stronger than their counterparts sintered at high temperatures (typically ≈ 2/3 T m). Hydrothermal Hot Pressing (HHP) was originally conceived in the context of sustainability and environmental preservation, with some examples being the concept of 'synthetic rock' for immobilisation of toxic/radioactive waste and the consolidation of high surface area porous ceramics for filtration. Follow up work on HHP considered the possibility of recreating in the lab bio-mineralisation using hydroxyapatite and bioglass (including hybrids) as proof of concept. Recent work on the Cold Sintering Process has demonstrated the potential to bridge the processing gap of multimaterial devices (sensors, batteries, 5G antennas, electronic components and biomaterials), enabling integration of polymers, ceramics and metals without degradation of the individual components both at the bulk and interface level. The absence of heating unlocks grain boundary design to an unprecedented level, offering further degrees of freedom in tuning functional properties. This review provides a wide perspective on room temperature consolidation, and covers the related but fragmented work published (≈ 450 papers) during the past 50 years, encompassing the relevant work developed in different disciplines including chemistry, physics, biology and geoscience. Liquid-assisted or liquid-mediated phenomena involving diffusion, plasticity, rheology, and grain growth are still largely unexplored in material science. The purpose of bringing together this literature is to build a general and multidisciplinary knowledge to guide future research directions. Both the reduction of energy consumption and carbon footprint are driving the growing interest in ULES, which could reinvent the concept of sintering, 'rendering kilns obsolete'. Also, ULES has the potential to produce new classes of materials that cannot be fabricated using conventional routes.
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