The microstructure and thermal conductivity of porous β-SiAlON ceramics fabricated by pressureless sintering with Y-α-SiAlON as the sintering additive

2021 ◽  
Author(s):  
Xueqing Li ◽  
Dongxu Yao ◽  
Kaihui Zuo ◽  
Yongfeng Xia ◽  
Jinwei Yin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Pressureless Sintering ◽  
Sintering Additive

scholarly journals Thermal conductivity of pressureless sintered silicon nitride materials with LiYO2 additive

2004 ◽  
Vol 36 (1) ◽  
pp. 3-10 ◽  
Author(s):  
B. Matovic ◽  
G. Rixecker ◽  
J. Golczewski ◽  
F. Aldinger
Keyword(s):  
Thermal Conductivity ◽  
Glassy Phase ◽  
Structural Parameters ◽  
Pressureless Sintering ◽  
Intergranular Phase ◽  
Sintering Additive ◽  
The Difference ◽  
Si3n4 Ceramics ◽  
Sintered Materials ◽  
Sintered Silicon

Si3N4 ceramics with different microstructures were prepared by pressureless sintering, using LiYO2 as a sintering additive. The effect of micro structural parameters, such as grain size and volume of intergranular phase on thermal conductivity was studied. Materials with thermal conductivities of 26-38 W?(m?K)-1 were obtained by changing the amount of sintering additive. The highest conductivity was measured for the material with the least amount of additive. Since the phase composition is the same for all sintered materials the difference in thermal conductivity is attributed to the amount of glassy phase in the grain-junctions. .

Microstructures in Pressureless Sintered AIN-SiC Ceramics

2001 ◽  
Vol 7 (S2) ◽  
pp. 1124-1125
Author(s):  
Y.D. Yu ◽  
I.-L. Tangen ◽  
M.-A. Einarsrud ◽  
R. Høier ◽  
T. Grande ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Integrated Circuits ◽  
Composite Ceramic ◽  
Substrate Material ◽  
Pressureless Sintering ◽  
Composite Ceramics ◽  
Metal Production ◽  
Sintering Additive ◽  
Sic Ceramics

Aluminum nitride (AlN) is known to have a high thermal conductivity and is one of the valid candidates as substrate material for integrated circuits. The material also has a potential in metal production and handling. However, AlN has only a moderate flexural strength and fracture toughness. It has been reported that SiCA1N composites (SiC/AIN ratio ≥ 50%) can be manufactured by means of pressureless sintering. Furthermore, it is possible to fabricate self-reinforced SiC-based materials with whisker-like crystals in composite ceramics by choosing appropriate sintering additive and condition. in the present study, we investigated the possibility to prepare in-situ formed SiC-whisker reinforced AlN-materials and studied the microstructure of the composite.An AlN-SiC composite ceramic sample (20 vol% SiC) was prepared for the investigation. The AlN-SiC composite was processed from a mixture of the starting powders with 2.5 wt% Al2O3-Y2O3 as a sintering additive.

Densification and Thermal Conductivity of Y2O3-Doped AlN Ceramics by Spark Plasma Sintering

2007 ◽  
Vol 352 ◽  
pp. 227-231 ◽  
Author(s):  
Qiang Shen ◽  
Z.D. Wei ◽  
Mei Juan Li ◽  
Lian Meng Zhang
Keyword(s):  
Thermal Conductivity ◽  
Grain Boundaries ◽  
Spark Plasma Sintering ◽  
Particle Surface ◽  
Boundary Phase ◽  
Homogeneous Microstructure ◽  
Densification Mechanism ◽  
Sintering Additive ◽  
Plasma Sintering ◽  
Spark Plasma

AlN ceramics doped with yttrium oxide (Y2O3) as the sintering additive were prepared via the spark plasma sintering (SPS) technique. The sintering behaviors and densification mechanism were mainly investigated. The results showed that Y2O3 addition could promote the AlN densification. Y2O3-doped AlN samples could be densified at low temperatures of 1600-1700oC in 20-25 minutes. The AlN samples were characterized with homogeneous microstructure. The Y-Al-O compounds were created on the grain boundaries due to the reactions between Y2O3 and Al2O3 on AlN particle surface. With increasing the sintering temperature, AlN grains grew up, and the location of grain boundaries as well as the phase compositions changed. The Y/Al ratio in the aluminates increased, from Y3Al5O12 to YAlO3 and to Y4Al2O9. High-density, the growth of AlN grains and the homogenous dispersion of boundary phase were helpful to improve the thermal conductivity of AlN ceramics. The thermal conductivity of 122Wm-1K-1 for the 4.0 mass%Y2O3-doped AlN sample was reached.

scholarly journals Improvement of mechanical properties of HfB2-based composites by incorporating in situ SiC reinforcement through pressureless sintering

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Ghadami ◽  
E. Taheri-Nassaj ◽  
H. R. Baharvandi ◽  
F. Ghadami
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Relative Density ◽  
Pressureless Sintering ◽  
Sintering Process ◽  
Vacuum Atmosphere ◽  
Sic Reinforcement ◽  
Microstructural Studies ◽  
Composite Samples

AbstractHfB2, Si, and activated carbon powders were selected to fabricate 0–30 vol% SiC reinforced HfB2-based composite. Pressureless sintering process was performed at 2050 °C for 4 h under a vacuum atmosphere. Microstructural studies revealed that in situ SiC reinforcement was formed and distributed in the composite according to the following reaction: Si + C = SiC. A maximum relative density of 98% was measured for the 20 vol% SiC containing HfB2 composite. Mechanical investigations showed that the hardness and the fracture toughness of these composites were increased and reached up to 21.2 GPa for HfB2-30 vol% SiC and 4.9 MPa.m1/2 for HfB2-20 vol% SiC, respectively. Results showed that alpha-SiC reinforcements were created jagged, irregular, and elongated in shape which were in situ formed between HfB2 grains and filled the porosities. Formation of alpha-SiC contributed to improving the relative density and mechanical properties of the composite samples. By increasing SiC content, an enhanced trend of thermal conductivity was observed as well as a reduced trend for electrical conductivity.

Pressureless sintering of boron carbide with Cr3C2 as sintering additive

2014 ◽  
Vol 34 (5) ◽  
pp. 1073-1081 ◽  
Author(s):  
Xiaoguang Li ◽  
Dongliang Jiang ◽  
Jingxian Zhang ◽  
Qingling Lin ◽  
Zhongming Chen ◽  
...  
Keyword(s):  
Boron Carbide ◽  
Pressureless Sintering ◽  
Sintering Additive

Improved thermal conductivity of β‐Si 3 N 4 ceramics by lowering SiO 2 /Y 2 O 3 ratio using YH 2 as sintering additive

2020 ◽  
Vol 103 (10) ◽  
pp. 5567-5572
Author(s):  
Weide Wang ◽  
Dongxu Yao ◽  
Hanqin Liang ◽  
Yongfeng Xia ◽  
Kaihui Zuo ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Sintering Additive

scholarly journals Effect of Sintering Temperature on the Properties of Highly Electrical Resistive SiC Ceramics as a Function of Y2O3-Er2O3 Additions

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4768
Author(s):  
Sheng Ge ◽  
Xiumin Yao ◽  
Yingying Liu ◽  
Hang Duan ◽  
Zhengren Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Electrical Resistivity ◽  
Sintering Temperature ◽  
Secondary Phase ◽  
Sintering Additive ◽  
Sic Ceramics ◽  
Plasma Sintering ◽  
Spark Plasma

Silicon carbide (SiC) ceramics with Y2O3-Er2O3 as sintering additives were prepared by spark plasma sintering (SPS). The effects of sintering temperatures and Y2O3-Er2O3 contents on the microstructure, thermal conductivity, electrical, and mechanical properties were investigated. The increasing of sintering temperatures promoted the densification of SiC ceramics, thus increasing the thermal conductivity and electrical resistivity. With the increase of the sintering additive contents, the electrical resistivity increased due to the formation of the electrical insulating network; and the thermal conductivity first increased and then decreased, which was related to the content and distribution of the secondary phase among the SiC grains. The SiC ceramics sintered at 2000 °C with 9 wt.% Y2O3-Er2O3 exhibited higher electrical resistivity and thermal conductivity, which were 4.28 × 109 Ω·cm and 96.68 W/m·K, respectively.

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