Mechanism of Consolidation of Nanoparticles in Diamond-Boron Oxide System at High Pressure and Temperature

2006 ◽  
Vol 518 ◽  
pp. 189-194 ◽  
Author(s):  
A. Bykov ◽  
G. Oleynik ◽  
A. Ragulya ◽  
I. Timofeeva ◽  
L. Klochkov ◽  
...  
Keyword(s):  
High Pressure ◽  
Liquid Phase ◽  
Boron Oxide ◽  
Diamond Powder ◽  
Oxide System ◽  
Sintering Process ◽  
High Pressure And Temperature ◽  
Ultradisperse Diamond ◽  
High Pressure Sintering ◽  
Diamond Powders

The high pressure sintering process of nanocrystalline diamond powder was studied. The influence of the liquid phase on the base of boron oxide was analyzed. The mechanism of cooperative-diffusive coalescence, which acts during sintering of ultradisperse diamond powders, is proposed.

Microstructural Study of Diamond Deformed Under High Pressure and Temperature

1985 ◽  
Vol 43 ◽  
pp. 230-231
Author(s):  
E. F. Koch
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Lattice Structure ◽  
Diamond Particle ◽  
Polycrystalline Diamond ◽  
Sintering Process ◽  
Ion Milling ◽  
Sintered Compact ◽  
Transmission Electron ◽  
High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

A Method for an Improvement in the Quality of Diamond Composite Thermostable Material

2010 ◽  
Vol 660-661 ◽  
pp. 844-847 ◽  
Author(s):  
Ana Lúcia Diegues Skury ◽  
Sérgio Neves Monteiro ◽  
Guerold Sergueevitch Bobrovinitchii ◽  
Marcia G. de Azevedo
Keyword(s):  
Polycrystalline Diamond ◽  
Diamond Powder ◽  
Polycrystalline Materials ◽  
Sintering Process ◽  
Compact Structure ◽  
Powder Consolidation ◽  
Fine Diamond ◽  
Sintered Diamond ◽  
Diamond Powders

It is still in focus the problem of obtaining high quality polycrystalline materials by means of sintering fine diamond powders. The most important task of this problem is the consolidation or improvement of the processed polycrystalline diamond. It is worldwide recognized that the plastic deformation of the diamond particles performs the most important role on the diamond powder consolidation. In some cases, the contact and shear tensions reconstruct the compact structure. In this work the sintering process used a mixture of micro and nanodiamonds. The sintering process was carried out in a toroidal high-pressure device. The effects of nanodiamond addition and sintering conditions on the microstructure and mechanical properties sintered diamond bodies were studied. The sintering parameters were pressure of 6.8 GPa and a temperature of 1850 K, and these conditions were maintained for 1 minute. Homogeneous sintered bodies were obtained, which have a Vickers' hardness over 40 GPa, and fracture toughness around 7.1 – 7.9 MPa.m1/2.

High-pressure and high-temperature sintering of nanostructured bulk NiAl materials

2009 ◽  
Vol 24 (6) ◽  
pp. 2089-2096 ◽  
Author(s):  
Shanmin Wang ◽  
Duanwei He ◽  
Yongtao Zou ◽  
Jianjun Wei ◽  
Li Lei ◽  
...  
Keyword(s):  
High Pressure ◽  
Indentation Hardness ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
High Pressure And Temperature ◽  
X Ray ◽  
High Pressure Sintering ◽  
Tentative Interpretation ◽  
Surface Shell ◽  
First Time

Nanostructured bulk NiAl materials were prepared at high pressure and temperature (0–5.0 GPa and 600–1500 °C, respectively). The sintered samples were characterized by x-ray diffraction, scanning electron microscope, density, and indentation hardness measurements. The results show that NiAl nanoparticles may have a compressed surface shell, which may be the reason why NiAl nanomaterials were difficult to densify sintering using conventional methods and why high-pressure sintering was an effective approach. We also observed that B2-structured NiAl could undergo a temperature-dependent phase transition and could be transformed into Al0.9Ni4.22 below 1000 °C for the first time. It is interesting to note that Vickers hardness decreased as grain size decreased below ∼30 nm, indicating that the inverse Hall-Petch effect may be observed in nano-polycrystalline NiAl (n-NiAl) samples. Moreover, a tentative interpretation was developed for high-pressure nanosintering, based on the shell-core model of nanoparticles.

Liquid phase assisted high pressure sintering of dense TiC nanoceramics

2018 ◽  
Vol 44 (15) ◽  
pp. 17972-17977 ◽  
Author(s):  
Lixin Liu ◽  
Bing Wang ◽  
Xuhai Li ◽  
Qiang He ◽  
Liang Xu ◽  
...  
Keyword(s):  
High Pressure ◽  
Liquid Phase ◽  
High Pressure Sintering

Sintering of a SiC-Diamond Composite with a New Setup for the Reactive Cell

2010 ◽  
Vol 660-661 ◽  
pp. 495-500
Author(s):  
Guerold Sergueevitch Bobrovinitchii ◽  
Ana Lúcia Diegues Skury ◽  
Sérgio Neves Monteiro ◽  
Rômulo Crespo Tardim
Keyword(s):  
High Pressure ◽  
Room Temperature ◽  
Diamond Powder ◽  
High Pressure Chamber ◽  
Sintering Process ◽  
Diamond Composite ◽  
Diamond Particles ◽  
Sintering Conditions ◽  
Infiltration Method ◽  
Composite Properties

Polycrystalline SiC-diamond composites have been fabricated by high pressure and high temperature, HPHT, sintering conditions using a Si infiltration method. However, infiltration of liquid Si around the diamond particles results not only in SiC but also in free Si, which causes deterioration of the composite properties. In this work, a novel sintering procedure was developed to avoid the formation of free Si in the composite structure. A disk composed of a mixture of graphite and Si was first press-molded at room temperature. The disk was then placed above the diamond powder inside a high pressure chamber used for the HPHT sintering process. This arrangement permitted to preferentially form liquid SiC, which infiltrates in between the diamond particles. Using this procedure, free Si formation is inhibited and the SiC-diamond composite forms a rigid structure with improved properties.

Fabrication of Cu2ZnSn(S,Se)4 solar cells by printing and high-pressure sintering process

2013 ◽  
Vol 1538 ◽  
pp. 179-183 ◽  
Author(s):  
Feng Gao ◽  
Tsuyoshi Maeda ◽  
Takahiro Wada
Keyword(s):  
Solid Solution ◽  
High Pressure ◽  
Solar Cells ◽  
Solar Cell ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Sintering Process ◽  
Device Structure ◽  
Gas Atmosphere ◽  
High Pressure Sintering

ABSTRACTWe fabricated Cu2ZnSn(SxSe1-x)4 (CZTSSe) solar cells by a printing and high-pressure sintering (PHS) process. First, the CZTSSe solid solution powders were synthesized by heating the elemental mixtures at 550oC for 5 h in an N2 gas atmosphere. We fabricated CZTSSe films by a printing and high-pressure sintering (PHS) process. The obtained dense CZTSSe film was post-annealed at 550oC for 10 min under an N2 +5% H2S gas atmosphere. We fabricated CZTSSe solar cells with the device structure of Ag/ITO/i-ZnO/CdS/CZTSSe/Mo/soda-lime glass. The CZTSSe solar cell showed an efficiency of 2.1%, with Voc of 272 mV, Jsc of 18.0 mA/cm2 and FF of 0.44.

Liquid Phase Migration during Diamond Powder Sintering by Infiltration Method

2012 ◽  
Vol 727-728 ◽  
pp. 450-455
Author(s):  
Ana Lúcia Diegues Skury ◽  
Guerold S. Bobrovinichii ◽  
Sérgio Neves Monteiro ◽  
Marcia G. de Azevedo ◽  
Apostolos Silva
Keyword(s):  
Liquid Phase ◽  
Initial Mixture ◽  
Diamond Powder ◽  
Metallic Binder ◽  
Powder Sintering ◽  
Cutting Inserts ◽  
Sintered Diamond ◽  
Diamond Powders ◽  
Infiltration Method ◽  
Petroleum Extraction

Compacts made of sintered diamond powder (DP) are not only extensively used but also essential cutting inserts for operations such as machining metal components or drilling rocks for petroleum extraction. The high pressure and high temperature (HPHT) sintering can be achieved either by an initial mixture of DP with a metallic binder or by first processing the DP at HPHT, which creates a sintered skeleton, followed by the molten metallic binder infiltration. This work investigates the infiltration of Cu, Co and Ni, as binders, into sintered diamond powders with different particles size. It was found that migration of the liquid phase through the sintered diamond skeleton complies with the Darci Law. The penetration coefficient varied from 0.89 x 10-7to 6.41 x 10-7μm2indicating that the migration is affected by several factors.

Sign in / Sign up

Export Citation Format

Share Document