Analytical Model of Heat Conduction in a Tubular Geometry With Application to a Nano-Structured Thermal Interface

2005 ◽  
Author(s):  
Anand Desai ◽  
James Geer ◽  
Bahgat Sammakia
Keyword(s):  
Thermal Conductivity ◽  
Power Dissipation ◽  
High Performance ◽  
Analytical Study ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Inner Diameter ◽  
Parametric Analyses ◽  
Interface Materials

Power dissipation in electronic devices is projected to increase significantly over the next ten years to the range of 50-150 Watts per cm2 for high performance applications [1]. This increase in power represents a major challenge to systems integration since the maximum device temperature needs to be around 100 C. One of the primary obstacles to the thermal management of devices operating at such high powers is the thermal resistance between the device and the heat spreader or heat sink that it is attached to. Typically the in situ thermal conductivity of interface materials is in the range of 1 to 4 W/mK, even though the bulk thermal conductivity of the material may be significantly higher. In order to improve the effective in-situ thermal conductivity of interface materials nanotubes are being considered as a possible addition to such interfaces. The primary approach taken in the current study is to analyze the enhancement of the thermal interface by adding carbon nano tubular cylinders that are oriented in the direction of transport. This paper presents the results of an analytical study of transport in a thermal interface material that is enhanced with carbon nanotubes. A variety of parametric analyses are carried out, such as by varying the inner diameter of the nanotube and the power dissipation, and the effect on spreading resistance is calculated. The results indicate that for high thermal conductivity nanotubes there is a significant increase in the effective thermal conductivity of the thermal interface material.

A Numerical Study of Transport in a Thermal Interface Material Enhanced With Carbon Nanotubes

2005 ◽  
Vol 128 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Anand Desai ◽  
Sanket Mahajan ◽  
Ganesh Subbarayan ◽  
Wayne Jones ◽  
James Geer ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
High Performance ◽  
Numerical Study ◽  
Temperature Drop ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
The Impact ◽  
Interface Materials

Power dissipation in electronic devices is projected to increase over the next 10years to the range of 150-250W per chip for high performance applications. One of the primary obstacles to the thermal management of devices operating at such high powers is the thermal resistance between the device and the heat spreader or heat sink that it is attached to. Typically the in situ thermal conductivity of interface materials is in the range of 1-4W∕mK, even though the bulk thermal conductivity of the material may be significantly higher. In an attempt to improve the effective in situ thermal conductivity of interface materials nanoparticles and nanotubes are being considered as a possible addition to such interfaces. This paper presents the results of a numerical study of transport in a thermal interface material that is enhanced with carbon nanotubes. The results from the numerical solution are in excellent agreement with an analytical model (Desai, A., Geer, J., and Sammakia, B., “Models of Steady Heat Conduction in Multiple Cylindrical Domains,” J. Electron. Packaging (to be published)) of the same geometry. Wide ranges of parametric studies were conducted to examine the effects of the thermal conductivity of the different materials, the geometry, and the size of the nanotubes. An estimate of the effective thermal conductivity of the carbon nanotubes was used, obtained from a molecular dynamics analysis (Mahajan, S., Subbarayan, G., Sammakia, B. G., and Jones, W., 2003, Proceedings of the 2003 ASME International Mechanical Engineering Congress and Exposition, Washington, D.C., Nov. 15–21). The numerical analysis was used to estimate the impact of imperfections in the nanotubes upon the overall system performance. Overall the nanotubes are found to significantly improve the thermal performance of the thermal interface material. The results show that varying the diameter of the nanotube and the percentage of area occupied by the nanotubes does not have any significant effect on the total temperature drop.

scholarly journals Graphene-Based Thermal Interface Materials: An Application-Oriented Perspective on Architecture Design

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1201 ◽  
Author(s):  
Le Lv ◽  
Wen Dai ◽  
Aijun Li ◽  
Cheng-Te Lin
Keyword(s):  
Thermal Conductivity ◽  
High Performance ◽  
Electronic Devices ◽  
Point Of View ◽  
Future Research ◽  
Thermal Interface Materials ◽  
Research Directions ◽  
Thermal Interface ◽  
Future Research Directions ◽  
Interface Materials

With the increasing power density of electrical and electronic devices, there has been an urgent demand for the development of thermal interface materials (TIMs) with high through-plane thermal conductivity for handling the issue of thermal management. Graphene exhibited significant potential for the development of TIMs, due to its ultra-high intrinsic thermal conductivity. In this perspective, we introduce three state-of-the-art graphene-based TIMs, including dispersed graphene/polymers, graphene framework/polymers and inorganic graphene-based monoliths. The advantages and limitations of them were discussed from an application point of view. In addition, possible strategies and future research directions in the development of high-performance graphene-based TIMs are also discussed.

scholarly journals Thermal Properties of the Graphene Composites: Application of Thermal Interface Materials

2018 ◽  
Vol 7 (4.33) ◽  
pp. 530
Author(s):  
Mazlan Mohamed ◽  
Mohd Nazri Omar ◽  
Mohamad Shaiful Ashrul Ishak ◽  
Rozyanty Rahman ◽  
Zaiazmin Y.N ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Matrix Material ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Uniform Thickness ◽  
Thermal Interface ◽  
Interface Materials ◽  
Main Material

Epoxy mixed with others filler for thermal interface material (TIM) had been well conducted and developed. There are problem occurs when previous material were used as matrix material likes epoxy that has non-uniform thickness of thermal interface material produce, time taken for solidification and others. Thermal pad or thermal interface material using graphene as main material to overcome the existing problem and at the same time to increase thermal conductivity and thermal contact resistance. Three types of composite graphene were used for thermal interface material in this research. The sample that contain 10 wt. %, 20 wt. % and 30 wt. % of graphene was used with different contain of graphene oxide (GO).  The thermal conductivity of thermal interface material is both measured and it was found that the increase of amount of graphene used will increase the thermal conductivity of thermal interface material. The highest thermal conductivity is 12.8 W/ (mK) with 30 w. % graphene. The comparison between the present thermal interface material and other thermal interface material show that this present graphene-epoxy is an excellent thermal interface material in increasing thermal conductivity.  

Development of a Compliant Nanothermal Interface Material

2011 ◽  
Author(s):  
David Shaddock ◽  
Stanton Weaver ◽  
Ioannis Chasiotis ◽  
Binoy Shah ◽  
Dalong Zhong
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Thermal Stresses ◽  
Performance Testing ◽  
High Thermal Conductivity ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Bondline Thickness ◽  
Interface Materials

The power density requirements continue to increase and the ability of thermal interface materials has not kept pace. Increasing effective thermal conductivity and reducing bondline thickness reduce thermal resistance. High thermal conductivity materials, such as solders, have been used as thermal interface materials. However, there is a limit to minimum bondline thickness in reducing resistance due to increased fatigue stress. A compliant thermal interface material is proposed that allows for thin solder bondlines using a compliant structure within the bondline to achieve thermal resistance <0.01 cm2C/W. The structure uses an array of nanosprings sandwiched between two plates of materials to match thermal expansion of their respective interface materials (ex. silicon and copper). Thin solder bondlines between these mating surfaces and high thermal conductivity of the nanospring layer results in thermal resistance of 0.01 cm2C/W. The compliance of the nanospring layer is two orders of magnitude more compliant than the solder layers so thermal stresses are carried by the nanosprings rather than the solder layers. The fabrication process and performance testing performed on the material is presented.

Challenges in Package Cooling of High Performance Servers

2007 ◽  
Author(s):  
Jie Wei
Keyword(s):  
Thermal Conductivity ◽  
Power Dissipation ◽  
High Performance ◽  
Heat Pipes ◽  
High Thermal Conductivity ◽  
Thermal Interface Material ◽  
Heat Spreader ◽  
Asymmetric Power ◽  
Heat Spreading ◽  
Silver Composite

Cooling technologies for dealing with high-density and asymmetric power dissipation are discussed, arising from thermal management of high performance server CPU-packages. In this paper, investigation and development of associated technologies are introduced from a viewpoint of industrial application, and attention is focused on heat conduction and removal at the package and heatsink module level. Based on analyses of power dissipation and package cooling characteristics, properties of a new metallic thermal interface material are presented where the Indium-Silver composite was evaluated for integrating the chip and its heat-spreader, effects of heat spreading materials on package thermal performance are investigated including high thermal conductivity diamond composites, and evaluations of enhanced heatsink cooling capability are illustrated where high thermal conductivity devices of heat pipes or vapor chambers were applied for improving heat spreading in the heatsink base.

scholarly journals RGO-Coated Polyurethane Foam/Segmented Polyurethane Composites as Solid–Solid Phase Change Thermal Interface Material

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3004
Author(s):  
Cong Zhang ◽  
Zhe Shi ◽  
An Li ◽  
Yang-Fei Zhang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phase Change ◽  
High Performance ◽  
In Situ Polymerization ◽  
Solid Phase ◽  
Thermal Interface Material ◽  
Segmented Polyurethane ◽  
Thermal Interface ◽  
Self Assembling

Thermal interface material (TIM) is crucial for heat transfer from a heat source to a heat sink. A high-performance thermal interface material with solid–solid phase change properties was prepared to improve both thermal conductivity and interfacial wettability by using reduced graphene oxide (rGO)-coated polyurethane (PU) foam as a filler, and segmented polyurethane (SPU) as a matrix. The rGO-coated foam (rGOF) was fabricated by a self-assembling method and the SPU was synthesized by an in situ polymerization method. The pure SPU and rGOF/SPU composite exhibited obvious solid–solid phase change properties with proper phase change temperature, high latent heat, good wettability, and no leakage. It was found that the SPU had better heat transfer performance than the PU without phase change properties in a practical application as a TIM, while the thermal conductivity of the rGOF/SPU composite was 63% higher than that of the pure SPU at an ultra-low rGO content of 0.8 wt.%, showing great potential for thermal management.

Comparison between CNT Thermal Interface Materials with Graphene Thermal Interface Material in Term of Thermal Conductivity

2020 ◽  
Vol 1010 ◽  
pp. 160-165
Author(s):  
Mazlan Mohamed ◽  
Mohd Nazri Omar ◽  
Mohamad Shaiful Ashrul Ishak ◽  
Rozyanty Rahman ◽  
Nor Zaiazmin Yahaya ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Mixed Material ◽  
Interface Materials ◽  
Main Material

Thermal interface material (TIM) had been well conducted and developed by using several material as based material. A lot of combination and mixed material were used to increase thermal properties of TIM. Combination between materials for examples carbon nanotubes (CNT) and epoxy had had been used before but the significant of the studied are not exactly like predicted. In this studied, thermal interface material using graphene and CNT as main material were used to increase thermal conductivity and thermal contact resistance. These two types of TIM had been compare to each other in order to find wich material were able to increase the thermal conductivity better. The sample that contain 20 wt. %, 40 wt. % and 60 wt. % of graphene and CNT were used in this studied. The thermal conductivity of thermal interface material is both measured and it was found that TIM made of graphene had better thermal conductivity than CNT. The highest thermal conductivity is 23.2 W/ (mK) with 60 w. % graphene meanwhile at 60 w. % of CNT only produce 12.2 W/ (mK thermal conductivity).

scholarly journals An Integrated Approach to Design and Develop High-Performance Polymer-Composite Thermal Interface Material

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 807
Author(s):  
Syed Sohail Akhtar
Keyword(s):  
Thermal Conductivity ◽  
Aspect Ratio ◽  
High Performance ◽  
High Thermal Conductivity ◽  
Thermal Interface Material ◽  
Design Stage ◽  
Filler Concentration ◽  
Melt Mixing ◽  
Thermal Interface ◽  
Wide Range

A computational framework based on novel differential effective medium approximation and mean-field homogenization is used to design high-performance filler-laden polymer thermal interface materials (TIMs). The proposed design strategy has the capability to handle non-dilute filler concentration in the polymer matrix. The effective thermal conductivity of intended thermal interface composites can be tailored in a wide range by varying filler attributes such as size, aspect ratio, orientation, as well as filler–matrix interface with an upper limit imposed by the shear modulus. Serval potential polymers and fillers are considered at the design stage. High-density polyethylene (HDPE) and thermoplastic polyurethane (TPU) with a non-dilute concentration (~60 vol%) of ceramic fillers exhibit high thermal conductivity (4–5 W m−1 K−1) without compromising the high compliance of TIMs. The predicted thermal conductivity and coefficient of thermal expansion are in excellent agreement with measured data of various binary composite systems considering HDPE, TPU, and polypropylene (PP) loaded with Al2O3 and AlN fillers in varying sizes, shapes, and concentrations, prepared via the melt-mixing and compression-molding route. The model also validates that manipulating filler alignment and aspect ratio can significantly contribute to making heat-conducting networks in composites, which results in ultra-high thermal conductivity.

Very High Performance Thermal Interface Material and Attachment Technology

2003 ◽  
Author(s):  
Ralph L. Webb ◽  
Jin Wook Paek ◽  
David Pickrell
Keyword(s):  
Thermal Conductivity ◽  
Thermal Degradation ◽  
Contact Resistance ◽  
High Performance ◽  
Copper Substrate ◽  
Alloy Layer ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Penn State

This paper provides an update on work at Penn State University on advanced thermal interface material (TIM) and attachment technology. The TIM concept consists of a “Low Melting Temperature Alloy” (LMTA) bonded to a thin copper substrate. The present work includes analytical modeling to separate the interface resistance (Rint) into “material” and “contact” resistance. Modeling indicates that contact resistance accounts for 1/3 of the interface resistance (Rint). Additional alloys have been identified that have thermal conductivity approximately three-times those identified in the previous 2002 publication. Thermal degradation of the LMTA TIM was also observed in the present work after extended thermal cycling above the melting point of the alloy. Possible mechanisms for this degradation are oxidation and contamination of the alloy layer rather than the inter-metallic diffusion. Use of the high thermal conductivity alloys, and soldered contact surfaces will provide very low Rint as well as minimizing the thermal degradation. It appears that Rint as small as, or less than, 0.005 cm2-K/W may be possible. Description of the modified Penn State TIM tester is provided, which will allow measurement of Rint = 0.01 cm2-K/W with less than 30% error.

Durability of Low Melt Alloys as Thermal Interface Materials

2015 ◽  
Author(s):  
Chandan K. Roy ◽  
Daniel K. Harris ◽  
Sushil Bhavnani ◽  
Michael C. Hamilton ◽  
Wayne Johnson ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Performance Testing ◽  
Thermal Interface Material ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Accelerated Life ◽  
Extended Aging ◽  
Interface Materials ◽  
Substrate Alloy

This paper focuses on developing a reliable thermal interface material (TIM) using low melt alloys (LMAs) containing gallium (Ga), indium (In), bismuth (Bi), and tin (Sn). The investigation described herein involved the in situ thermal performance of the LMAs as well as performance evaluation after accelerated life cycle testing, which included isothermal aging at 130°C and thermal cycling from −40°C to 80°C. Three alloys (75.5Ga &24.5In, 100Ga, and 51In, 32.5Bi &16.5Sn) were chosen for testing the thermal performance. Testing methodologies used follow ASTM D5470 protocols and the results are compared with some commercially available TIMs. The LMAs-substrate interaction was investigated by applying the alloys using different surface treatments (copper and tungsten). Measurements show that the alloys did survive extended aging and cycling depending upon the substrate-alloy combinations.

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