scholarly journals Study of the Hydrolytic Stability of Fine-Grained Ceramics Based on Y2.5Nd0.5Al5O12 Oxide with a Garnet Structure under Hydrothermal Conditions

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2152
Author(s):  
Liudmila Alekseeva ◽  
Aleksey Nokhrin ◽  
Maksim Boldin ◽  
Eugeniy Lantsev ◽  
Artem Murashov ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hydrolytic Stability ◽  
Garnet Structure ◽  
Hydrothermal Conditions ◽  
Static Mode ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Grain Boundary Segregations ◽  
High Test

The hydrolytic stability of ceramics based on Y2.5Nd0.5Al5O12 oxide with a garnet structure obtained by the spark plasma sintering (SPS) method has been studied. The tests were carried out in distilled water under hydrothermal conditions in an autoclave and, for comparison, in a static mode at room temperature. The mechanism of leaching of Y and Nd from the ceramics was investigated. It has been shown that at “low” temperatures (25 and 100 °C), the destruction of pores occured, and the intensity of the leaching process was limited by the diffusion of ions from the inner part of the sample to the surface. At “high” test temperatures (200 and 300 °C), intense destruction of the ceramic grain boundaries was observed. It was assumed that the accelerated leaching of neodymium is due to the formation of grain-boundary segregations of Nd3+ in sintered ceramics.

Effect of spark plasma sintering parameters on microstructure and room-temperature hardness and toughness of fine-grained boron carbide (B4C)

2013 ◽  
Vol 33 (2) ◽  
pp. 361-369 ◽  
Author(s):  
Bibi Malmal Moshtaghioun ◽  
Francisco Luis Cumbrera-Hernández ◽  
Diego Gómez-García ◽  
Santiago de Bernardi-Martín ◽  
Arturo Domínguez-Rodríguez ◽  
...  
Keyword(s):  
Boron Carbide ◽  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Boron Carbide B4c

Preparation of Fine-Grained CeO2–SiC Ceramics for Inert Fuel Matrices by Spark Plasma Sintering

2020 ◽  
Vol 56 (12) ◽  
pp. 1307-1313
Author(s):  
L. S. Alekseeva ◽  
A. V. Nokhrin ◽  
M. S. Boldin ◽  
E. A. Lantsev ◽  
A. I. Orlova ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Fine Grained ◽  
Sic Ceramics ◽  
Plasma Sintering ◽  
Spark Plasma

Ultra-Fine Grained Ti-15Mo Alloy Prepared by Powder Metallurgy

2018 ◽  
Vol 941 ◽  
pp. 1276-1281
Author(s):  
Anna Terynková ◽  
Jiří Kozlík ◽  
Kristína Bartha ◽  
Tomáš Chráska ◽  
Josef Stráský
Keyword(s):  
Powder Metallurgy ◽  
Bulk Material ◽  
Alpha Phase ◽  
Full Density ◽  
Fine Grained ◽  
Cryogenic Milling ◽  
Aircraft Manufacturing ◽  
Plasma Sintering ◽  
Beta Matrix ◽  
Spark Plasma

Ti-15Mo alloy belongs to metastable β-Ti alloys that are currently used in aircraft manufacturing and Ti15Mo alloy is a perspective candidate for the use in medicine thanks to its biotolerant composition. In this study, Ti15Mo alloy was prepared by advanced techniques of powder metallurgy. The powder of gas atomized Ti-15Mo alloy was subjected to cryogenic milling to achieve ultra-fine grained microstructure within the powder particles. Powder was subsequently compacted using spark plasma sintering (SPS). The effect of cryogenic milling on the microstructure and phase composition of final bulk material after SPS was studied by scanning electron microscopy. Sintering at 750°C was not sufficient for achieving full density in gas atomized powder, while milled material could be successfully sintered at this temperature. Alpha phase particles precipitated during sintering and their size, as well as the size of beta matrix grains, was strongly affected by the sintering temperature.

scholarly journals The Extrusion and SPS of Zirconium–Copper Powders and Studies of Selected Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3560
Author(s):  
Tomasz Skrzekut ◽  
Grzegorz Boczkal ◽  
Adam Zwoliński ◽  
Piotr Noga ◽  
Lucyna Jaworska ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compounds ◽  
Room Temperature ◽  
Intermetallic Phase ◽  
Extrusion Process ◽  
Strength Properties ◽  
Plasma Sintering ◽  
Copper Powders ◽  
Spark Plasma ◽  
Zirconium Copper

Zr-2.5Cu and Zr-10Cu powder mixtures were consolidated in the extrusion process and using the spark plasma sintering technique. In these studies, material tests were carried out in the fields of phase composition, microstructure, hardness and tensile strength for Zr-Cu materials at room temperature (RT) and 400 °C. Fractography analysis of materials at room temperature and 400 °C was carried out. The research took into account the anisotropy of the materials obtained in the extrusion process. For the nonequilibrium SPS process, ZrCu2 and Cu10Zr7 intermetallic compounds formed in the material at sintering temperature. Extruded materials were composed mainly of α-Zr and ZrCu2. The presence of intermetallic compounds affected the reduction in the strength properties of the tested materials. The highest strength value of 205 MPa was obtained for the extruded Zr-2.5Cu, for which the samples were cut in the direction of extrusion. For materials with 10 wt.% copper, more participation of the intermetallic phase was formed, which lowered the mechanical properties of the obtained materials. In addition to brittle intermetallic phases, the materials were characterized by residual porosity, which also reduced the strength properties.

scholarly journals Superplasticity of fine-grained alumina obtained by spark plasma sintering

2021 ◽  
Vol 1758 (1) ◽  
pp. 012031
Author(s):  
A A Popov ◽  
V N Chuvil’deev ◽  
M S Boldin ◽  
A V Nokhrin ◽  
E A Lantsev ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals A Study of the Impact of Graphite on the Kinetics of SPS in Nano- and Submicron WC-10%Co Powder Compositions

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 331-363
Author(s):  
Eugeniy Lantcev ◽  
Aleksey Nokhrin ◽  
Nataliya Malekhonova ◽  
Maksim Boldin ◽  
Vladimir Chuvil'deev ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid Phase ◽  
Continuous Heating ◽  
Diffusion Creep ◽  
Hard Alloys ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact ◽  
Kinetics Of

This study investigates the impact of carbon on the kinetics of the spark plasma sintering (SPS) of nano- and submicron powders WC-10wt.%Co. Carbon, in the form of graphite, was introduced into powders by mixing. The activation energy of solid-phase sintering was determined for the conditions of isothermal and continuous heating. It has been demonstrated that increasing the carbon content leads to a decrease in the fraction of η-phase particles and a shift of the shrinkage curve towards lower heating temperatures. It has been established that increasing the graphite content in nano- and submicron powders has no significant effect on the SPS activation energy for “mid-range” heating temperatures, QS(I). The value of QS(I) is close to the activation energy of grain-boundary diffusion in cobalt. It has been demonstrated that increasing the content of graphite leads to a significant decrease in the SPS activation energy, QS(II), for “higher-range” heating temperatures due to lower concentration of tungsten atoms in cobalt-based γ-phase. It has been established that the sintering kinetics of fine-grained WC-Co hard alloys is limited by the intensity of diffusion creep of cobalt (Coble creep).

Microstructure of Cu-TiB2 Nanocomposite during Spark Plasma Sintering

2004 ◽  
Vol 449-452 ◽  
pp. 1113-1116 ◽  
Author(s):  
Young Soon Kwon ◽  
Ji Soon Kim ◽  
Jong Jae Park ◽  
Hwan Tae Kim ◽  
Dina V. Dudina
Keyword(s):  
Spark Plasma Sintering ◽  
Titanium Diboride ◽  
Copper Matrix ◽  
Microstructural Change ◽  
Simultaneous Action ◽  
Fine Grained ◽  
Pulse Electric Current ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Pulse Electric

Microstructural change of TiB2-Cu nanocomposite during spark plasma sintering (SPS) was investigated. Under simultaneous action of pressure, temperature and pulse electric current titanium diboride nanoparticles distributed in copper matrix move, agglomerate and form a interpenetrating phase composite with a fine-grained skeleton. Increase of SPS temperatures and holding times promotes the densification of sintered compacts due to local melting of copper matrix.

Formation of a unique glass by spark plasma sintering of a zeolite

2009 ◽  
Vol 24 (10) ◽  
pp. 3241-3245 ◽  
Author(s):  
Lianjun Wang ◽  
Wan Jiang ◽  
Lidong Chen ◽  
Zhijian Shen
Keyword(s):  
Spark Plasma Sintering ◽  
Glass Sample ◽  
Room Temperature ◽  
Vickers Microhardness ◽  
Simple Approach ◽  
Electron Microscopic ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Spark Plasma

A simple approach, order–disorder transition (ODT), has been developed to synthesize a novel glass using ZSM-5 as starting materials. In this process, the ZSM-5 powders were pressed uniaxially in a graphite die and rapidly sintered using spark plasma sintering (SPS). High-resolution transmission electron microscopic images revealed that a few crystalline zeolite fragments were still preserved locally inside the SPS consolidated sample. Vickers microhardness and fracture toughness of this as-prepared transparent glass sample at room temperature reaches 7.3 ± 0.2 GPa and 2.0 ± 0.3MPa·m1/2, respectively. It is very interesting that these novel bulk transparent glasses exhibit ultraviolet photoluminescence (PL) properties at about ∼360 nm.

Dielectric properties of fine-grained BaTiO3 prepared by spark-plasma-sintering

2004 ◽  
Vol 83 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Baorang Li ◽  
Xiaohui Wang ◽  
Longtu Li ◽  
Hui Zhou ◽  
Xingtao Liu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Spark Plasma Sintering ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals Mechanical Milling-Assisted Spark Plasma Sintering of Fine-Grained W-Ni-Mn Alloy

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1323 ◽  
Author(s):  
Yanlin Pan ◽  
Daoping Xiang ◽  
Ning Wang ◽  
Hui Li ◽  
Zhishuai Fan
Keyword(s):  
Spark Plasma Sintering ◽  
Mechanical Milling ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Interface Fracture ◽  
Composite Powders ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Binding Phase ◽  
Spark Plasma

Fine-grained W-6Ni-4Mn alloys were fabricated by spark plasma sintering (SPS) using mechanical milling W, Ni and Mn composite powders. The relative density of W-6Ni-4Mn alloy increases from 71.56% to 99.60% when it is sintered at a low temperature range of 1000–1200 °C for 3 min. The spark plasma sintering process of the alloy can be divided into three stages, which clarify the densification process of powder compacts. As the sintering temperature increases, the average W grain size increases but remains at less than 7 µm and the distribution of the binding phase is uniform. Transmission electron microscopy (TEM) observation reveals that the W-6Ni-4Mn alloy consists of the tungsten phase and the γ-(Ni, Mn, W) binding phase. As the sintering temperature increases, the Rockwell hardness and bending strength of alloys initially increases and then decreases. The optimum comprehensive hardness and bending strength of the alloy are obtained at 1150 °C. The main fracture mode of the alloys is W/W interface fracture.

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