High Thermal Conductivity Silicone Elastomer Doped with Graphene Nanoplatelets and Eutectic GaIn Liquid Metal Alloy

A high thermal conductivity thermal paste can be developed by mixing the oxidized liquid metal alloy (OLMA) with graphene. Four kinds of graphene-OLMA pastes were synthesized at graphene concentrations of 0.25 wt%, 0.75 wt%, 1.5 wt%, and 2.0 wt%, respectively. The paste structures were characterized by MicroXCT-400, which can be used to readily measure the air pocket size, and their thermal conductivities measured by a laser flash analysis method. It is found that the OLMA structure is very different from the liquid metal alloy (LMA), and a small amount of air pockets were formed in the OLMA. The air pocket size significantly affected the thermal conductivity of the graphene-OLMA paste. When the graphene concentration increased, as shown in Fig. 1(c)-(e), the paste's thermal conductivity increased. However, more air pockets were formed around the graphene. In particular, when the graphene concentration increased to 2.0 wt%, clusters of graphene, as shown in Fig. 1(f), were formed resulting in the formation of big air pockets in the thermal paste, which directly affected the thermal conductivity as shown in Fig. 1(g). We thought that when the graphene concentration increases, the thermal conductivity should increases. But the results show that it was not and then we used MicroCT to see the internal structure of the thermal paste and found that the air pockets were formed and significantly affects the thermal performance.

Download Full-text

Highly Conductive Thermal Paste of Liquid Metal Alloy Dispersed With Copper Particles

Volume 1: Heat Transfer in Energy Systems; Thermophysical Properties; Theory and Fundamentals in Heat Transfer; Nanoscale Thermal Transport; Heat Transfer in Equipment; Heat Transfer in Fire and Combustion; Transport Processes in Fuel Cells and Heat Pipes; Boiling and Condensation in Macro, Micro and Nanosystems ◽

10.1115/ht2016-7374 ◽

2016 ◽

Cited By ~ 1

Author(s):

Gen Li ◽

Yulong Ji ◽

Mengke Wu ◽

Hongbin Ma

Keyword(s):

Thermal Conductivity ◽

Liquid Metal ◽

Thermal Contact ◽

Copper Particle ◽

Metal Alloy ◽

Copper Particles ◽

Thermal Paste ◽

Liquid Metal Alloy ◽

Thermal Pastes ◽

Thermal Conductivities

In this paper, a kind of highly conductive thermal paste is investigated, which consists of liquid metal alloy (LMA) and copper particles. The LMA used in the current research is a gallium-indium-tin eutectic alloy (Ga62.5In21.5Sn16). The copper particles dispersing into LMA have an average diameter of 9 μm. During the dispersing process, a degassing process was conducted in order to reduce air bubbles and increase the thermal conductivity of the investigated paste. A new method based on laser flash (LFA) was used to test the total thermal conductivities of the samples. Three types of thermal pastes were prepared and tested, i.e., LMA, oxidized liquid metal alloy (OLMA), and OLMA mixed with copper particles. Results show that when LMA, OLMA, and OLMA mixed with copper particles at a ratio of 5wt%, the resulting thermal conductivities of the investigated thermal pastes can achieve 44.48 W/mK, 13.55 W/mK, and 24.34 W/mK, which result in the corresponding thermal contact resistances of 4.044 mm2K/W, 5.638 mm2K/W, and 4.075 mm2K/W, respectively. In addition, the effect of the copper particle ratio on the thermal performance was investigated. Results show that when the ratio of copper particles increased from 5wt% to 10wt%, the thermal conductivity of investigated thermal paste increased from 24.34 W/mK to 29.07 W/mK, and the thermal contact resistance decreased from 4.075 mm2K/W to 3.37 mm2K/W.

Download Full-text

Carbon Nanotube as Thermal Interface Material Enhanced with Liquid Metal Alloy

Proceedings of the 15th International Heat Transfer Conference ◽

10.1615/ihtc15.hte.009448 ◽

2014 ◽

Author(s):

Yulong Ji ◽

Gen Li ◽

Chao Chang ◽

Yuqing Sun ◽

Hongbin Ma

Keyword(s):

Carbon Nanotube ◽

Liquid Metal ◽

Metal Alloy ◽

Thermal Interface Material ◽

Thermal Interface ◽

Liquid Metal Alloy

Download Full-text

Dynamic Processes During Pulsed Gas Injection Into Liquid Column

Volume 3: Thermal-Hydraulics ◽

10.1115/icone24-60615 ◽

2016 ◽

Author(s):

P. D. Lobanov ◽

O. N. Kashinsky ◽

A. S. Kurdyumov ◽

N. A. Pribaturin

Keyword(s):

Liquid Metal ◽

Gas Phase ◽

Gas Injection ◽

High Amplitude ◽

Metal Alloy ◽

Dynamic Processes ◽

Flow Parameters ◽

Liquid Metal Alloy ◽

Inner Diameter ◽

Gas Volume

An experimental study of dynamic processes during pulsed gas injection into quiescent liquids was performed. Both water and low melting temperature metal alloy were used as test liquids. Air and argon were used as gas phase. The test sections were vertical cylindrical columns 25 and 68 mm inner diameter. Measurements of flow parameters during gas injection were performed. Water – air experiments were performed at room temperature, the temperature of liquid metal alloy was 135 deg C. Time records of pressure in the liquid and in gas phase above the liquid were obtained. Measurements of liquid temperature and level of liquid surface were performed. It was shown that at pulse gas injection into liquid metal high amplitude pressure fluctuation may arise. Also the fluctuation variation of the free surface of the liquid may appear which are connected with the oscillations of the gas volume. Experimental data obtained may be used for verification & validation of modern CFD codes.

Download Full-text