Fabrication and Microstructure of Electrically Conductive AlN with High Thermal Conductivity

2011 ◽  
Vol 484 ◽  
pp. 57-60
Author(s):  
Takafumi Kusunose ◽  
Tohru Sekino ◽  
Koiichi Niihara
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Rare Earth ◽  
Sintering Temperature ◽  
Rare Earth Oxide ◽  
High Thermal Conductivity ◽  
Boundary Phase ◽  
Sudden Increase ◽  
Electrically Conductive ◽  
Electrical Conductivities

The electrically conductive AlN with high thermal conductivity were successfully fabricated by sintering AlN with a composite additive of 1wt.% Y2O3 and 4wt.% CeO2 in carbon-reduced atmosphere at over 1600 °C. The sudden increase in electrical conductivity is thought to be caused by transition of grain boundary phase from rare-earth oxide to rare-earth oxycarbide. Their electrical conductivities and thermal conductivities increased with increasing sintering temperature. Additionally, sintering temperature influenced the resultant microstructures.

Effect of rare-earth species on the wear properties of α sialon and β silicon nitride ceramics under tribochemical type conditions

2004 ◽  
Vol 19 (9) ◽  
pp. 2750-2758 ◽  
Author(s):  
Mark I. Jones ◽  
Kiyoshi Hirao ◽  
Hideki Hyuga ◽  
Yukihiko Yamauchi
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Wear Behavior ◽  
Rare Earth Oxide ◽  
Lower Amount ◽  
Boundary Phase ◽  
Wear Properties ◽  
Sintering Additives ◽  
Nitride Ceramics ◽  
Worn Surfaces

The wear properties under low loads of β Si3N4 and α sialon materials sintered with different rare-earth oxide sintering additives have been studied under dry sliding conditions using block-on-ring wear tests. All the worn surfaces showed an absence of fracture and smooth surfaces with the presence of an oxygen-rich filmlike debris indicating tribochemically induced oxidation of the surfaces. Extensive grain boundary removal was observed on the worn surfaces thought to be due to adhesion between this silicate phase and the tribochemically oxidized surfaces. The resistance to such oxidation and the properties of the residual grain boundary phase are thought to be important parameters affecting the wear behavior under the present testing conditions. For both the β Si3N4 and α sialon materials, there was an increase in wear resistance with decreasing cationic radius of the rare earth, thought to be due to improved oxidation resistance, and this was more remarkable in the case of the sialon materials where the incorporation of the sintering additives into the Si3N4 structure results in a lower amount of residual boundary phase.

Stable, highly concentrated suspensions for electronic and ceramic materials applications

1991 ◽  
Vol 6 (5) ◽  
pp. 1082-1093 ◽  
Author(s):  
I. Sushumna ◽  
R.K. Gupta ◽  
E. Ruckenstein
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Ceramic Materials ◽  
Rheological Characteristics ◽  
Concentrated Suspensions ◽  
Thermal Paste ◽  
Electrical Conductivities ◽  
Liquid Suspensions ◽  
Very High ◽  
Highly Loaded

Highly concentrated solid-in-liquid suspensions find applications in a number of areas such as electronics, ceramics, paints, coatings, etc. Highly loaded, stable suspensions which exhibit desirable rheological characteristics (moderate viscosity, shear thinning behavior, thixotropy, and a small yield stress, for example), and which have high thermal or electrical conductivities are frequently sought after. We describe here some techniques which can be used to obtain such highly concentrated suspensions. These involve employing mixed size grades of particles and effective dispersants. For thermal paste applications, for example, compliant pastes of up to 78 vol. % solids with thermal conductivity values as high as 6 W/mK (hence, a few times greater than the values reported previously by others), low electrical conductivity, and moderate viscosity have been prepared by mixing different particle size grades of materials such as Al2O3, SiC, AlN, Al, and diamond. Effective dispersants, both commercial as well as those synthesized in our laboratory as novel variations of previously known molecular architectures, have been used to facilitate the achievement of these very high loading and stable suspensions.

Numerical Analysis to Lead Free Solder/Intermetallic Interconnect With Application of Wiedemann-Franz-Lorenz Relation

2012 ◽  
Author(s):  
Yao Yao ◽  
Jared Fry ◽  
Morris Fine ◽  
Leon Keer
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Material Properties ◽  
Interfacial Crack ◽  
Electrical Current ◽  
Lead Free ◽  
Lead Free Solder ◽  
Electrical Conductivities ◽  
Free Solder

Due to the limitation of available experimental data for thermal conductivity of lead free solder and Intermetallic Compound (IMC) materials, the Wiedemann-Franz-Lorenz (WFL) relation is presented in this paper as a possible solution to predict thermal conductivity with known electrical conductivity. The method is based upon the fact that heat and electrical transport both involve the free electrons. The thermal and electrical conductivities of Cu, Ni, Sn, and different Sn rich lead free solder and IMC materials are studied by employing the WFL relation. Generally, the analysis to the experimental data shows that the WFL relation is obeyed in both solder alloy and IMC materials especially matches close to the relation for Sn, with a positive deviation from the theoretical Lorenz number. Thus, with the available electrical conductivity data, the thermal conductivity of solder and IMC materials can be obtained based on the proper WFL relation, vice versa. With the reduction of size of electronic devices and solder interconnects, it has been observed experimentally that solders fail by crack nucleation and propagation near the interface of IMC and bulk solder. A coupled thermal-electrical finite element analysis is performed to study the behavior of lead free solder/IMC interconnects under different electrical current densities. The joule heating, temperature concentration and electrical current concentration effects with a crack propagating near the interface of solder and IMC are investigated numerically. Solder and IMC material properties predicted using the WFL relation are adopted in the computational model. The effects of different thermal and electrical conductivities of solder and IMC materials on interfacial crack tip temperature are analyzed in the present study. By applying the WFL relation, the amount of experiments required to determine the material properties for different lead free solder/IMC interconnects can be significantly reduced, which can lead to pronounced saving of time and cost.

scholarly journals Epsilon-negative BaTiO3/Cu composites with high thermal conductivity and yet low electrical conductivity

2020 ◽  
Vol 6 (1) ◽  
pp. 145-151 ◽  
Author(s):  
Zhongyang Wang ◽  
Kai Sun ◽  
Peitao Xie ◽  
Yao Liu ◽  
Qilin Gu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Thermal Conductivity

scholarly journals Electrical Conductivity of the Coexisting System Containing Molten Carbonates and Rare-Earth Oxide

2019 ◽  
Vol 33 (7) ◽  
pp. 439-447 ◽  
Author(s):  
Minoru Mizuhata ◽  
Toshifumi Ohashi ◽  
Alexis B. Béléké
Keyword(s):  
Electrical Conductivity ◽  
Rare Earth ◽  
Rare Earth Oxide ◽  
Molten Carbonates

Effects of rare-earth oxide and alumina additives on thermal conductivity of liquid-phase-sintered silicon carbide

2003 ◽  
Vol 18 (8) ◽  
pp. 1854-1862 ◽  
Author(s):  
You Zhou ◽  
Kiyoshi Hirao ◽  
Yukihiko Yamauchi ◽  
Shuzo Kanzaki
Keyword(s):  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Rare Earth ◽  
Liquid Phase ◽  
Point Defects ◽  
Rare Earth Oxide ◽  
Low Oxygen ◽  
Sic Ceramics ◽  
Sintered Silicon ◽  
Thermal Conductivities

SiC ceramics were prepared from a β–SiC powder doped with two different sintering additives—a mixture of La2O3and Y2O3and a mixture of Al2O3and Y2O3—by hot pressing and annealing. Their microstructures, phase compositions, lattice oxygen contents, and thermal conductivities were evaluated. The SiC doped with rare-earth oxides attained thermal conductivities in excess of 200 W/(m K); however, the SiC doped with additives containing alumina had thermal conductivities lower than 71 W/(m K). The high thermal conductivity of the rare-earth-oxide-doped SiC was attributed to the low oxygen content in SiC lattice, high SiC–SiC contiguity, and lack of β– to α–SiC polytypic transformation. The low thermal conductivity of the alumina-doped SiC was attributed to the point defects resulting from the dissolution of Al2O3into SiC lattice and the occurrence of polytypic transformation.

Electrically Conductive Polymer Nanocomposites with High Thermal Conductivity

2016 ◽  
pp. 255-280
Author(s):  
Prabhakar R. Bandaru ◽  
B.-W. Kim ◽  
S. Pfeifer ◽  
R. S. Kapadia ◽  
S.-H. Park
Keyword(s):  
Thermal Conductivity ◽  
Polymer Nanocomposites ◽  
Conductive Polymer ◽  
High Thermal Conductivity ◽  
Electrically Conductive
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