Effect of LiCl·H2O on Sintering Properties of MgO from Bischofite

2013 ◽  
Vol 813 ◽  
pp. 364-371 ◽  
Author(s):  
Qiong Zhu Huang ◽  
Gui Min Lu ◽  
Jian Guo Yu
Keyword(s):  
Solid Solution ◽  
Liquid Phase ◽  
Solid Solutions ◽  
Oxygen Vacancies ◽  
Salt Lake ◽  
Liquid Phase Sintering ◽  
Promoting Effect ◽  
Sintering Properties ◽  
Qarhan Salt Lake ◽  
Natural Brine

Effect of LiCl·H2O on sintering properties of MgO prepared from natural brine from Qarhan Salt Lake, crystalline bischofite and MgCl2·6H2O(AR) was studied. The results showed that LiCl·H2O of addition exceeded 1 wt% had promoting effect on sintering of magnesia prepared from MgCl2·6H2O(AR). While 1.5 wt% LiCl·H2O was added, the bulk density of magnesia was 3.40 g/cm3, and the relative density was 95.0%. With 0.5 wt% LiCl·H2O, the bulk densities of magnesia prepared from crystalline bischofite and brine were 3.04 and 3.10 g/cm3, and the relative densities increased by 8.4% and 14.8%, respectively. The main mechanism for promoting MgO sintering with LiCl·H2O was that Li2O produced by hydrolysis solubilized in MgO to form solid solutions and oxygen vacancies which were favorable to sintering. The main reasons for promoting sintering of brine magnesia with LiCl·H2O were solid solution and liquid phase sintering, while the main reason was solid solution for magnesia from crystalline bischofite and MgCl2·6H2O(AR).

Sintering and Performance of MgO from Bischofite with ZrO2 Additive

2013 ◽  
Vol 455 ◽  
pp. 11-17 ◽  
Author(s):  
Qiong Zhu Huang ◽  
Gui Min Lu ◽  
Jian Guo Yu
Keyword(s):  
Monoclinic Phase ◽  
Salt Lake ◽  
Liquid Phase Sintering ◽  
Cubic Phase ◽  
Sintering Process ◽  
Promotive Effect ◽  
Sintering Properties ◽  
And Performance ◽  
Qarhan Salt Lake ◽  
Natural Brine

Effect of ZrO2 on sintering properties of MgO prepared from natural brine from Qarhan Salt Lake, crystalline bischofite and MgCl2·6H2O(AR) was studied. The results showed that ZrO2 of addition exceeded 1 wt% had promotive effect on sintering of magnesia prepared from MgCl2·6H2O(AR). While 1.5 wt% ZrO2 was added, the bulk density of sample was 3.37 g/cm3, and relative density was 94.1%. With 1 wt% ZrO2, the bulk densities of magnesia prepared from crystalline bischofite and brine were 3.10 and 3.27 g/cm3, and the relative densities increased by 10.0% and 19.6%, respectively. The main reasons for promoting MgO sintering with ZrO2 were that monoclinic phase ZrO2 converted to cubic phase Zr2O and excess ZrO2 reacted with MgO to generate Mg0.13Zr0.87O1.87, which activated lattice and promoted the diffusion of ions during sintering process. In addition, liquid phase sintering was also one of the main reasons for promoting the sintering of brine magnesia.

SOLID SOLUTION FORMATION DURING LIQUID PHASE SINTERING

1986 ◽  
Vol 47 (C1) ◽  
pp. C1-441-C1-445
Author(s):  
E. KOSTIĆ ◽  
S. J. KISS ◽  
D. CEROVIĆ
Keyword(s):  
Solid Solution ◽  
Liquid Phase ◽  
Liquid Phase Sintering ◽  
Solid Solution Formation ◽  
Solution Formation

scholarly journals Effects of Boron Addition on the Microstructure and Mechanical Properties of (Ti,Ta)(C,N)-Co Based Cermets

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 787
Author(s):  
Ernesto Chicardi ◽  
Francisco José Gotor Martínez
Keyword(s):  
Mechanical Properties ◽  
Liquid Phase ◽  
Intermetallic Compound ◽  
Solid Solutions ◽  
General Trend ◽  
Liquid Phase Sintering ◽  
Binder Phase ◽  
Boron Addition ◽  
Sintering Additive ◽  
Microstructure And Mechanical Properties

In this work, a titanium–tantalum carbonitride based cermet, with cobalt as the binder phase and boron as a sintering additive, was developed by a mechanically induced self-sustaining reaction process using two different methodologies. The boron additive was added to prevent the formation of brittle intermetallic compounds generally formed during the liquid phase sintering step due to the excessive ceramic dissolution into the molten binder phase. A systematic study was carried out to understand the effects of boron addition on the nature of the phases, microstructure, and mechanical properties of cermets. With the boron addition, the formation of two different boride solid solutions, i.e., (Ti,Ta)B2 and (Ti,Ta)3B4, was observed. Moreover, the nature of the binder was also modified, from the (Ti,Ta)Co2 brittle intermetallic compound (for cermets without boron addition) to ductile and tough (Ti,Ta)Co3 and α-Co phases (for cermets with boron addition). These modifications caused, as a general trend, the increase of hardness and toughness in cermets.

Formation of solid solutions between SiC and AlN during liquid-phase sintering

1996 ◽  
Vol 29 (1-3) ◽  
pp. 1-6 ◽  
Author(s):  
Jong-Kook Lee ◽  
Hidehiko Tanaka ◽  
Hwan Kim
Keyword(s):  
Liquid Phase ◽  
Solid Solutions ◽  
Liquid Phase Sintering

Microstructure of TiB2 liquid phase sintered with Ni3Al

1983 ◽  
Vol 41 ◽  
pp. 62-63
Author(s):  
P. Angelini ◽  
J. Bentley ◽  
C. B. Finch ◽  
P. S. Sklad
Keyword(s):  
Solid Solution ◽  
Thermal Expansion ◽  
Liquid Phase ◽  
Electrical Properties ◽  
Grain Growth ◽  
Hot Pressing ◽  
Liquid Phase Sintering ◽  
Intergranular Phase ◽  
Phase Development ◽  
Al Powder

TiB2 is a ceramic material which possesses exceptional thermal, chemical, and electrical properties. Commercial powders can be formed into bulk pieces by hot pressing at temperatures near 2000°C. However, this produces excessive grain growth which can lead to cracking and low mechanical integrity due to the relatively large anisotropic thermal expansion of the TiB2 grains. Liquid phase sintering can be used to produce structural forms of TiB2 by hot pressing at temperatures near 1450°C. This process limits the TiB2 grain growth but introduces an intergranular phase. Previous work used Ni as a binder and under most hot-pressing conditions this resulted in the formation of a Ni3B intergranular phase. Additional binders are being considered to understand the phase development during liquid-phase sintering and to improve the properties of the bonded TiB2 forms.The present research concerns the use of Ni3Al as a binder for TiB2. The Ni3Al powder was a physical mixture of 32 wt % NiAl and 68 wt % of a solid solution of 95 at. % Ni with 5 at. % Al powders.

scholarly journals Enhanced sintering and nonlinear dielectric properties of Ba0.6Sr0.4TiO3 ceramics with a small amount of lithium additive

2019 ◽  
Vol 51 (3) ◽  
pp. 295-307
Author(s):  
Xiao-Fei Zhang ◽  
Xiao-Bin Xie ◽  
Qing Xu ◽  
Min Chen ◽  
Dong-Chu Chen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Liquid Phase ◽  
Figure Of Merit ◽  
Liquid Phase Sintering ◽  
Sintering Behavior ◽  
Precursor Method ◽  
Nonlinear Dielectric ◽  
Bias Electric Field ◽  
Sintering Properties ◽  
Citrate Precursor

The powders with the nominal compositions of Ba0.6Sr0.4TiO3+x wt.% Li2CO3 (x=0 and x=1.0) were synthesized by a citrate precursor method. The sintering behavior, structure and dielectric properties of the ceramic specimens were investigated. Compared with the lithium-free specimen (x=0), the lithium-added specimen (x=1.0) showed appreciably enhanced sintering properties, achieving a relative density of 96.0% after sintering at 900?C. The enhanced sintering properties were related to a liquid-phase sintering mechanism. The origin of the liquid-phase was explained. The effects of the liquid-phase on the densification progress of the lithium-added specimen in different sintering stages were elucidated. The lithium addition was found to be beneficial to the nonlinear dielectric properties. The ceramic specimen with x=1.0 exhibited a figure-of-merit of 106 under a bias electric field of 20 kV/cm, higher by ~60% than the value (67) for the specimen with x=0.

Hardness Limits of SiC and Si3N4 Ceramic Materials

2005 ◽  
Vol 287 ◽  
pp. 311-316 ◽  
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.

The Effect of TiC on the Liquid Phase Sintering of SiC Ceramics with Al2O3 and Y2O3 Additives

2014 ◽  
Vol 602-603 ◽  
pp. 197-201 ◽  
Author(s):  
Han Qin Liang ◽  
Xiu Min Yao ◽  
Hui Zhang ◽  
Xue Jian Liu ◽  
Zheng Ren Huang
Keyword(s):  
Solid Solution ◽  
Fracture Toughness ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Uniform Distribution ◽  
Vickers Hardness ◽  
Liquid Phase Sintering ◽  
Homogeneous Microstructure ◽  
Ceramic Phase ◽  
Sic Ceramics

Low fracture toughness of SiC ceramics limits their applications for the low reliability. Inclusion of second ceramic phase improves the toughness of SiC ceramics. In this presentation, SiC ceramics with 5wt% TiC was pressureless liquid phase sintered (LPS) with the additives of Al2O3 and Y2O3 to ~98% theoretical density at the temperature of 1920 °C for 1 hour. The TiC grains were well distributed and good for the uniform distribution of the liquid phase YAG in the SiC matrix, which resulted in the homogeneous microstructure with fine SiC grains. The existence of TiC benefited the formation of elongated α-SiC, which favored the bridging and deflection of cracks so that the fracture toughness was improved to some extent. Because the amount of TiC was so small that the inherent properties of SiC was not degraded. The flexural strength and Vickers hardness maintained similar with the LPS SiC without TiC. The phase compositions detected in the sample were SiC, YAG and TiC. And no solid-solution of SiC and TiC was revealed by the mapping of EDS.

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