Liquid Phase Sintering of Aluminum Nitride

2007 ◽  
Vol 554 ◽  
pp. 181-188 ◽  
Author(s):  
Katsutoshi Komeya ◽  
Junichi Tatami
Keyword(s):  
Liquid Phase ◽  
Aluminum Nitride ◽  
Dihedral Angle ◽  
Lattice Constant ◽  
Sintered Density ◽  
Liquid Phase Sintering ◽  
Sintering Behavior ◽  
Sintering Aids ◽  
Powder Compacts ◽  
Oxygen Impurities

Liquid-phase sintering of aluminum nitride (AlN) with additives was reviewed. The most important innovation was the discovery of critical sintering aids for AlN densification, specifically rare-earth compounds and alkali-earth compounds. These additives are extremely valuable for increasing thermal conductivity by trapping and removing oxygen in the AlN lattice during firing. Consequently, thermal conductivities in AlN ceramics of 100 to 260W/mK were developed. We also studied the effects of parameters such as raw powder, additives, composition, and firing condition in liquid-phase sintering with AlN-sintering aids, focusing on oxygen impurities in the system. The sintering behavior of powder compacts was investigated by evaluating the densification, the lattice constant c for AlN, and the dihedral angle of the interface between the AlN grains and the grain boundary liquid-phase. In our results, the change in densification was closely related to changes in the lattice constant c and the dihedral angle. That is, the sintered density increased with an increase in the oxygen dissolved in the AlN grains and with the improvement in wettability between the solid and liquid phase.

Liquid Phase Sintering of α-Si3N4 by Spark Plasma Sintering

2007 ◽  
Vol 336-338 ◽  
pp. 1062-1064 ◽  
Author(s):  
Fa Qiang Yan ◽  
Fei Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Liquid Phase ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Sintering Behavior ◽  
Sintering Aids ◽  
Factors Influencing ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Si3n4 Ceramics

In this study, spark plasma sintering (SPS) was applied to prepare α-Si3N4 ceramics of different densities with magnesia, silicon dioxide, alumina as the sintering aids. The sintering behavior and liquid phase sintering (LPS) mechanism were discussed and the factors influencing the density of the prepared samples were analyzed. Microstructures of sintered samples were observed and the phase compositions were analyzed. The results showed that α-Si3N4 ceramics can be sintered by SPS based on the reaction among α-Si3N4 and sintering additives which lead to the liquid phase and the density can be well controlled from 2.48 to 3.09 g/cm3 while the content of the sintering aids changes from 10% to 28.5% and sintering temperature from 1400°C to 1500°C.

scholarly journals Microwave and conventional sintering of premixed and prealloyed Cu-12Sn bronze

2003 ◽  
Vol 35 (2) ◽  
pp. 49-65 ◽  
Author(s):  
G. Sethi ◽  
A. Upadhyaya ◽  
D. Agrawal
Keyword(s):  
Comparative Analysis ◽  
Solid State ◽  
Liquid Phase ◽  
Sintered Density ◽  
Liquid Phase Sintering ◽  
Sintering Behavior ◽  
Conventional Furnace ◽  
Microwave Furnace ◽  
Conventional Sintering ◽  
Sintering Conditions

The aim of the present investigation is to study the sintering behavior of the Cu-12Sn bronze system in both, a microwave furnace as well as a conventional furnace. The powders prepared by premixed and prealloyed routes were sintered in the range of solid state, transient and supersolidus liquid phase sintering conditions. The comparative analysis is based on the sintered density, densification parameter, hardness, macrostructures and microstructures of the samples.

scholarly journals The Influences of Sio2 on the Sintering Behavior and the Properties of Na+- Β/Β"-Al2O3 Solid Electrolyte

2019 ◽  
Vol 25 (3) ◽  
pp. 328-334
Author(s):  
Sung-Tae LEE ◽  
Dae-Han LEE ◽  
Sung-Ki LIM
Keyword(s):  
Solid State ◽  
Liquid Phase ◽  
Ionic Conductivity ◽  
Sintered Density ◽  
Phase Relationship ◽  
Liquid Phase Sintering ◽  
Sio2 Content ◽  
Sintering Behavior ◽  
Impedance Analyzer ◽  
The Relationship

SiO2-doped Na+-β/β″-Al2O3 was synthesized via a solid-state reaction, and the relationship between the SiO2 content and properties of Na+-β/β″-Al2O3 was investigated. Respective specimens were doped with 0 – 5 wt.% SiO2 as a liquid phase sintering promotor and sintered. The specimens were characterized by XRD, SEM, densimeter and impedance analyzer. In the sintered samples, the phase fraction of β″-Al2O3 decreased as the SiO2 content increased, whereas the relative sintered density was enhanced with the inclusion of less than 0.7 wt.% SiO2. The relative sintered density of Na+- β/β″-Al2O3 sintered specimen with 0.7 wt.% SiO2 doping reached 99.2 % of the theoretical density and the sintered density decreased when the amount of SiO2 was larger than 1 wt.% result from excessive liquid-phase formation during sintering. Similarly, the ionic conductivity of SiO2-doped Na+-β/β″-Al2O3 was enhanced by doping with a small amount of SiO2, whereas the addition of more than 1 wt.% SiO2 negatively affected the ionic conductivity of Na+-β/β″-Al2O3 due to a decrease in the sintered density and unfavorable phase relationship. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.14246

Sintering Characteristics of Micro-Zn Paste Containing Sn-3.0Ag-0.5Cu Nanoparticles

2012 ◽  
Vol 249-250 ◽  
pp. 939-944
Author(s):  
Sang Soo Chee ◽  
Jong Hyun Lee
Keyword(s):  
Electrical Resistivity ◽  
Liquid Phase ◽  
Transient Liquid Phase ◽  
Liquid Phase Sintering ◽  
Sintering Behavior ◽  
Short Lifespan ◽  
Lower Melting Point ◽  
Transient Liquid Phase Sintering ◽  
Sintering Characteristics ◽  
Very High

The transient liquid-phase sintering behavior of micro-Zn/nano-Sn-3.0Ag-0.5Cu (SAC) pastes was examined at a temperature of 190 °C as a function of the volume of ultrafine (~12.4 nm) SAC nanoparticles present. SAC nanoparticles have lower melting point drop than the bulk SAC particles. Although successful linkage at the interface between all Zn particles was not accomplished in all sintered samples, the number of linkages increased marginally with a decrease in the SAC content. As a result, the electrical resistivity of the sintered samples decreased with the decrease in the SAC content; however, the resistivities were still very high in all samples. Microstructural observations indicated that the observed results were mainly due to the short lifespan of the liquid phase caused by the coarsening of SAC nanoparticles during heating.

Low-Temperature Sintering and Microwave Dielectric Properties of CaWO4-Mg2SiO4 Ceramics

2014 ◽  
Vol 933 ◽  
pp. 12-16 ◽  
Author(s):  
Chung Long Pan ◽  
Ping Cheng Chen ◽  
Tsu Chung Tan ◽  
Wei Cheng Lin ◽  
Chun Hsu Shen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Liquid Phase Sintering ◽  
Low Temperature Sintering ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Microwave Dielectric

The effect of V2O5addition on the microstructures and the microwave dielectric properties of 0.9CaWO4-0.1Mg2SiO4(9CWMS) ceramics prepared by conventional solid-state routes have been investigated. The V2O5were selected as liquid phase sintering aids to lower the sintering temperature of 9CWMS ceramics. A small amount of V2O5(0.25~1 wt%) were used for sintering aid and led to high densification at 1050°C. The dielectric properties of 9CWMS ceramics with V2O5additions are strongly dependent on the densification, the microstructure. As the amount of V2O5additives increased from 0.25 to 1.0 wt%, the dielectric constantsεrdecreased following the trend with density. The quality valuesQdecreased with the increase of V2O5amount for all sintering temperatures. The 0.25 wt% V2O5-doped 0.9CaWO4-0.1Mg2SiO4ceramicssintered at 1080°C for 2 h had the optimum dielectric properties: εr= 5.7;Q×f= 73000 (at 14 GHz).

scholarly journals Sintering Behaviors, Microstructure, and Microwave Dielectric Properties of CaTiO3–LaAlO3 Ceramics Using CuO/B2O3 Additions

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4187 ◽  
Author(s):  
Min-Hang Weng ◽  
Chihng-Tsung Liauh ◽  
Shueei-Muh Lin ◽  
Hung-Hsiang Wang ◽  
Ru-Yuan Yang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Liquid Phase Sintering ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Microwave Dielectric ◽  
Quality Factor Q

The effect of CuO/B2O3 additions on the sintering behaviors, microstructures, and microwave dielectric properties of 0.95LaAlO3–0.05CaTiO3 ceramics is investigated. It is found that the sintering temperatures are lowered efficiently from 1600 °C to 1350 °C, as 1 wt % CuO, 1 wt % B2O3, and 0.5 wt % CuO +0.5 wt % B2O3 are used as the sintering aids due to the appearance of the liquid phase sintering. The microwave dielectric properties of 0.95LaAlO3–0.05CaTiO3 ceramics with the sintering aid additions are strongly related to the densification and the microstructure of the sintered ceramics. At the sintering temperature of 1300 °C, the 0.95LaAlO3–0.05CaTiO3 ceramic with 0.5 wt % CuO + 0.5 wt % B2O3 addition shows the best dielectric properties, including a dielectric constant (εr) of 21, approximate quality factor (Q × f) of 22,500 GHz, and a temperature coefficient of the resonant frequency (τf) of −3 ppm/°C.

3D Phase-Field Simulation and Characterization of Microstructure Evolution during Liquid Phase Sintering

2014 ◽  
Vol 87 ◽  
pp. 132-138 ◽  
Author(s):  
Hamed Ravash ◽  
Eckard Specht ◽  
Jef Vleugels ◽  
Nele Moelans
Keyword(s):  
Liquid Phase ◽  
Grain Boundary ◽  
Coordination Number ◽  
Dihedral Angle ◽  
Phase Field ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Liquid Phase Sintering ◽  
Study Phase ◽  
Solid Liquid

Liquid phase sintering (LPS) is widely used as a materials processing technique for hightemperature applications. In LPS, particle-particle contact size and distribution, 3-D coordination number, connectivity, and contiguity are important microstructure parameters which, to a large extent, determine the mechanical properties of the sintered materials. These features all depend on the grain size, solid volume fraction and dihedral angle during sintering. The dihedral angle is an important parameter in LPS. It is the angle formed between the 2 solid-liquid interfaces at the intersection of a grain boundary with the liquid. A higher solid volume fraction, on the other hand, favors a larger 3-D coordination number, connectivity, and contiguity. In practice, studying the correlation between these parameters and direct measurement of them is not a trivial task. Among them, 3-D measurement of dihedral angle is believed to be the most challenging one. In the current study, phase-field modeling is employed to simulate LPS in two phase systems (solid and liquid). Simulations are performed for the different ratios of grain boundary to solid-liquid energies and the different solid volume fractions. To create initial structures with high solid volume fraction, an advanced particle packing algorithm is employed. An extended sparse bounding-box algorithm is used to speed-up the computations and makes it computationally efficient for 3-D simulations. Contiguity, connectivity, and three dimensional coordination number were measured in the self similar regime. The results were compared with empirical rules and experimental data and are used to estimate the mean 3-D dihedral angle.

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