Evaluation of dynamic viscosity and rheological properties of ceramic materials during liquid phase sintering by numerical-experimental procedure

The present paper deals with the nano-indentation of SiC-micro and Si3N4/SiCmicro/ nano ceramic materials. The investigated SiC-micro and Si3N4/SiC-micro/nano ceramics were prepared by liquid phase sintering. Liquid phase was formed from different sintering additives (Y2O3, Yb2O3, Sm2O3). In the case of Si3N4/SiC-micro/nano ceramics the SiC nano-grains were created from SiNC amorphous powder. SiNC precursor decomposed to SiC and Si3N4 particles during sintering. The comparison of nano- and macro-hardness of investigated ceramic materials showed that nano-hardness is significantly higher. The indentation modulus correlated with the measured nano-hardness. Remarkable influence of grain boundaries and SiC nano-inclusions on hardness was observed.

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The silicon carbide materials' structure modification's influence on their dynamical properties

NOVYE OGNEUPORY (NEW REFRACTORIES) ◽

10.17073/1683-4518-2018-7-39-44 ◽

2018 ◽

pp. 39-44

Author(s):

S. N. Perevislov ◽

I. A. Bespalov ◽

M. V. Tomkovitch

Keyword(s):

Silicon Carbide ◽

Liquid Phase ◽

Ceramic Materials ◽

Liquid Phase Sintering ◽

Sic Ceramic ◽

Dynamical Properties

The SiC ceramic materials have been prepared by both of the reactive and liquid-phase sintering. The modofcation of their structure was carried out while preparing by means of the reinforcing SiC-flament introduction and by synthesizing of the grain selfreinforced structure. The armor-protection capacity was defned by estimation of the bullet penetration delay time.Ill.5. Ref. 18. Tab. 4.

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Hardness Limits of SiC and Si3N4 Ceramic Materials

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.287.311 ◽

2005 ◽

Vol 287 ◽

pp. 311-316 ◽

Cited By ~ 2

Author(s):

Miroslav Balog ◽

Pavol Šajgalík ◽

Zoltán Lenčéš ◽

Miroslav Hnatko ◽

Jozef Kečkéš

Keyword(s):

Liquid Phase ◽

Grain Boundary ◽

Solid Solutions ◽

Ceramic Materials ◽

Liquid Phase Sintering ◽

Boundary Phase ◽

Polymer Precursor ◽

Micro Hardness ◽

Boundary Composition

Nano- and macro-hardness of SiC and Si3N4 based ceramic materials prepared by liquid phase sintering were evaluated. The applied loads were 3.5 mN and 9.81 N, respectively. The measurements showed that the nano-hardness of both ceramics is substantially higher compared to the macro-hardness. The influence of solid solutions and grain boundary composition on the hardness of SiC-based ceramics was studied. The macro-hardness is strongly dependent on the grain boundary composition while the nano-hardness was nearly the same for all tested samples with different Re2O3-AlN additives. In the case of Si3N4 based ceramics the SiC nano-inclusions content was varied. As a source of SiC nanoinclusions and grain boundary phase modifierSiNC polymer precursor has been used. Nano- as well as micro-hardness increased with increasing SiC content. Present paper deals with the explanation of both results.

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Microanalysis of silicate glass films grown on α-Al2O3 by pulsed-laser deposition

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100148022 ◽

1993 ◽

Vol 51 ◽

pp. 438-439

Author(s):

Michael P. Mallamaci ◽

James Bentley ◽

C. Barry Carter

Keyword(s):

Liquid Phase ◽

Single Crystal ◽

Pulsed Laser Deposition ◽

Pulsed Laser ◽

Ceramic Materials ◽

Laser Deposition ◽

Triple Junctions ◽

Ion Milling ◽

Multicomponent Oxides ◽

Glass Films

Glass-oxide interfaces play important roles in developing the properties of liquid-phase sintered ceramics and glass-ceramic materials. Deposition of glasses in thin-film form on oxide substrates is a potential way to determine the properties of such interfaces directly. Pulsed-laser deposition (PLD) has been successful in growing stoichiometric thin films of multicomponent oxides. Since traditional glasses are multicomponent oxides, there is the potential for PLD to provide a unique method for growing amorphous coatings on ceramics with precise control of the glass composition. Deposition of an anorthite-based (CaAl2Si2O8) glass on single-crystal α-Al2O3 was chosen as a model system to explore the feasibility of PLD for growing glass layers, since anorthite-based glass films are commonly found in the grain boundaries and triple junctions of liquid-phase sintered α-Al2O3 ceramics.Single-crystal (0001) α-Al2O3 substrates in pre-thinned form were used for film depositions. Prethinned substrates were prepared by polishing the side intended for deposition, then dimpling and polishing the opposite side, and finally ion-milling to perforation.

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Effect of furnace atmosphere and silica content on the consolidation behaviour of magnesia partially stabilised zirconia

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178410 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1056-1057

Author(s):

J. Drennan ◽

R.H.J. Hannink ◽

D.R. Clarke ◽

T.M. Shaw

Keyword(s):

Liquid Phase ◽

Silica Content ◽

Liquid Phase Sintering ◽

Furnace Atmosphere ◽

Boundary Phase ◽

Analytical Electron ◽

Analytical Electron Microscope ◽

Series Of Experiments ◽

Compositional Gradients ◽

Mobile Liquid

Magnesia partially stabilised zirconia (Mg-PSZ) ceramics are renowned for their excellent nechanical properties. These are effected by processing conditions and purity of starting materials. It has been previously shown that small additions of strontia (SrO) have the effect of removing the major contaminant, silica (SiO2).The mechanism by which this occurs is not fully understood but the strontia appears to form a very mobile liquid phase at the grain boundaries. As the sintering reaches the final stages the liquid phase is expelled to the surface of the ceramic. A series of experiments, to examine the behaviour of the liquid grain boundary phase, were designed to produce compositional gradients across the ceramic bodies. To achieve this, changes in both silica content and furnace atmosphere were implemented. Analytical electron microscope techniques were used to monitor the form and composition of the phases developed. This paper describes the results of our investigation and the presentation will discuss the work with reference to liquid phase sintering of ceramics in general.

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Microstructure and microanalysis of sintered Fe-Nd-B permanent magnets

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178082 ◽

1990 ◽

Vol 48 (4) ◽

pp. 990-991

Author(s):

Mahesh Chandramouli

Keyword(s):

Electron Microscope ◽

Liquid Phase ◽

Permanent Magnets ◽

Phase Distribution ◽

Energy Dispersive Spectrometer ◽

Nucleation And Growth ◽

Liquid Phase Sintering ◽

Domain Wall Energy ◽

Oxide Phases ◽

Scanning Electron

Magnetization reversal in sintered Fe-Nd-B, a complex, multiphase material, occurs by nucleation and growth of reverse domains making the isolation of the ferromagnetic Fe14Nd2B grains by other nonmagnetic phases crucial. The magnets used in this study were slightly rich in Nd (in comparison to Fe14Nd2B) to promote the formation of Nd-oxides at multigrain junctions and incorporated Dy80Al20 as a liquid phase sintering addition. Dy has been shown to increase the domain wall energy thus making nucleation more difficult while Al is thought to improve the wettability of the Nd-oxide phases.Bulk polished samples were examined in a JEOL 35CF scanning electron microscope (SEM) operated at 30keV equipped with a Be window energy dispersive spectrometer (EDS) detector in order to determine the phase distribution.

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