Densification process for spherical glass powders with the same particle size by hydrothermal hot pressing

1991 ◽  
Vol 26 (23) ◽  
pp. 6448-6452 ◽  
Author(s):  
Kazuyuki Hosoi ◽  
Susumu Kawai ◽  
Kazumichi Yanagisawa ◽  
Nakamichi Yamasaki
Keyword(s):  
Particle Size ◽  
Hot Pressing ◽  
Densification Process ◽  
Spherical Glass ◽  
Glass Powders

Pressure assisted sintering of Al2O3–Y2O3 glass microspheres: sintering conditions, grain size, and mechanical properties of sintered ceramics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Anna Prnová ◽  
Jana Valúchová ◽  
Monika Michálková ◽  
Beáta Pecušová ◽  
Milan Parchovianský ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Hot Pressing ◽  
Pechini Method ◽  
Sol Gel ◽  
Applied Pressure ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Glass Microspheres ◽  
Amorphous Powders

Abstract Glass microspheres with yttria-alumina eutectic composition (76.8 mol % Al2O3 and 23.2 mol % Y2O3) were prepared by sol-gel Pechini method and flame synthesis with or without subsequent milling. Prepared amorphous powders were studied by X-ray powder diffraction (XRD), particle size analysis (PSA), scanning electron microscopy (SEM) and differential thermal analysis (DTA). Hot pressing (HP), rapid hot pressing (RHP) and spark plasma sintering (SPS) were used to sinter amorphous precursor powders at 1600 °C without holding time (0 min). The preparation process including milling step resulted in amorphous powders with narrower particle size distribution and smaller particle size. All applied pressure assisted sintering techniques resulted in dense bulk samples with fine grained microstructure consisting of irregular α-Al2O3 and Y3Al5O12 (YAG) grains. Milling was beneficial in terms of final microstructure refinement and mechanical properties of sintered materials. A material with the Vickers hardness of HV = (17.1 ± 0.3) GPa and indentation fracture resistance of (4.2 ± 0.2) MPa.m1/2 was prepared from the powder milled for 12 h.

Hot Pressing of cBN Ceramics with Al Binder

2006 ◽  
Vol 45 ◽  
pp. 1364-1370 ◽  
Author(s):  
H.S.L. Sithebe ◽  
David S. McLachlan ◽  
I.J. Sigalas ◽  
Mathias Herrmann
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Hot Pressing ◽  
Theoretical Density ◽  
Pressing Temperature ◽  
Oxide Layers ◽  
Effect Of Particle Size ◽  
Full Densification ◽  
Scanning Electron

Al-cBN cermets have been hot pressed at temperature between 800oC and 1100oC and pressure of 50MPa in vacuum. The effect of particle size of the starting powders as well as the effect of starting compositions and temperature was investigated. The materials could only densify up to 84-92% of theoretical density. After hot pressing at 800oC only Al and cBN could be observed by XRD, whereas higher hot pressing temperature result in the formation of AlN and AlB2 which retard the densification. The microstructure of the hot pressed material was studied using scanning electron microscopy. It was observed that oxide layers exist at the interface between Al and cBN phases. The presence of these oxide layers resulted in blocking the Al from spreading and therefore preventing full densification.

Preparation and Microstructure of Al/Ti3SiC2 Nanocomposite

2007 ◽  
Vol 121-123 ◽  
pp. 191-194
Author(s):  
Wan Li Gu ◽  
Liu Feng
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
Microstructure Evolution ◽  
Powder Mixture ◽  
Hot Pressing ◽  
Milling Process ◽  
Steel Ball ◽  
Mixed Powder ◽  
Ball Milling Process ◽  
Ball Milling Technique

An Al-5vol%Ti3SiC2 nanocomposite has been prepared by ball milling technique. Steel ball, agate ball and zirconia ball were selected during the ball milling process and then the microstructure evolution of the powder mixture was investigated. The homogenous fine mixed powder can be obtained with zirconia ball, whereas the conglomeration will be formed in the case of steel ball and agate ball. The bulk Al/Ti3SiC2 nanocomposite was fabricated by hot pressing technique. The effects of the particle size and agglomerate state of Ti3SiC2, as well as the microstructure of Al/Ti3SiC2 nanocomposite were studied by SEM and TEM. It was found that the nanosized Ti3SiC2 particle could be obtained during the ball milling process and distributed in aluminium homogenously.

scholarly journals Nickel-graphite composites of variable architecture by graphitization-accompanied spark plasma sintering and hot pressing and their response to phase separation

2015 ◽  
Vol 47 (3) ◽  
pp. 237-248 ◽  
Author(s):  
D.V. Dudina ◽  
A.V. Ukhina ◽  
B.B. Bokhonov ◽  
V.I. Mali ◽  
A.G. Anisimov ◽  
...  
Keyword(s):  
Particle Size ◽  
Spatial Distribution ◽  
Phase Separation ◽  
Spark Plasma Sintering ◽  
Hot Pressing ◽  
Porous Structures ◽  
Plasma Sintering ◽  
Porous Graphite ◽  
Spark Plasma ◽  
Graphite Composites

We report the formation and phase separation response of nickel-graphite composites with variable-architecture phases by graphitization-accompanied consolidation via Spark Plasma Sintering and hot pressing. It was shown that the application of pressure during consolidation is crucial for the occurrence of graphitization and formation of 3D graphite structures. We evaluated the suitability of the synthesized composites as precursors for making porous structures. Nickel behaved as a space holder with the particle size and spatial distribution changing during consolidation with the temperature and determining the structure of porous graphite formed by phase separation by dissolution in HCl. The response of the consolidated Ni-Cgr to separation of carbon by its burnout in air was studied. The result of the carbon removal was either the formation of a dense and continuous NiO film on the surface of the compacts or oxidation through the compact thickness. The choice between these two options depended on the density of the compacts and on the presence of carbon dissolved in nickel. It was found that during the burnout of graphite from Ni-Cgr composites, sintering, rather than formation of pores, dominated.

scholarly journals Densification Process of Sepiolite under Hydrothermal Hot-pressing.

1993 ◽  
Vol 40 (3) ◽  
pp. 355-358
Author(s):  
Yoshiaki Fukushima ◽  
Xianping Meng ◽  
Kazumichi Yanagisawa ◽  
Nakamichi Yamasaki
Keyword(s):  
Hot Pressing ◽  
Densification Process

Molten Salts Synthesis and Dielectric Properties of PMN-PT Ceramics

2005 ◽  
Vol 475-479 ◽  
pp. 1153-1156 ◽  
Author(s):  
Shi Xi Zhao ◽  
Qiang Li ◽  
Feng Bing Song
Keyword(s):  
Particle Size ◽  
Dielectric Properties ◽  
Molten Salts ◽  
Piezoelectric Properties ◽  
Perovskite Phase ◽  
Theoretical Density ◽  
Densification Process ◽  
Single Perovskite Phase ◽  
Dielectric And Piezoelectric Properties

Single perovskite phase PMN-PT powders had been synthesized using molten salts method. The powders of PMN-PT synthesized by MSS had submicrometer particle size and high sinterability, which beneficial to an enhancement of the densification process and a decrease of the sintering temperatures. These advantages have an important bearing on the dielectric properties of these materials. The density of ceramics sintered at 1175°C was up to 98% of the theoretical density. These ceramics had excelled dielectric and piezoelectric properties.

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