High performance phase change thermal interface materials based on porous graphitic carbon spheres-paraffin wax composite

2014 ◽  
Author(s):  
Zhihua Cao ◽  
Kai Zhang ◽  
Guoping Zhang ◽  
Matthew M. F. Yuen ◽  
Ping Gu ◽  
...  
Keyword(s):  
Phase Change ◽  
High Performance ◽  
Porous Graphitic Carbon ◽  
Graphitic Carbon ◽  
Paraffin Wax ◽  
Thermal Interface Materials ◽  
Carbon Spheres ◽  
Thermal Interface ◽  
Interface Materials

Characterization of Metallically Bonded Carbon Nanotube-Based Thermal Interface Materials Using a High Accuracy 1D Steady-State Technique

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Joseph R. Wasniewski ◽  
David H. Altman ◽  
Stephen L. Hodson ◽  
Timothy S. Fisher ◽  
Anuradha Bulusu ◽  
...  
Keyword(s):  
Steady State ◽  
High Performance ◽  
Applied Pressure ◽  
Test Facility ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Thermal Interface Resistance ◽  
Vertically Aligned ◽  
Performance Results ◽  
Interface Materials

The next generation of thermal interface materials (TIMs) are currently being developed to meet the increasing demands of high-powered semiconductor devices. In particular, a variety of nanostructured materials, such as carbon nanotubes (CNTs), are interesting due to their ability to provide low resistance heat transport from device-to-spreader and compliance between materials with dissimilar coefficients of thermal expansion (CTEs), but few application-ready configurations have been produced and tested. Recently, we have undertaken major efforts to develop functional nanothermal interface materials (nTIMs) based on short, vertically aligned CNTs grown on both sides of a thin interposer foil and interfaced with substrate materials via metallic bonding. A high-precision 1D steady-state test facility has been utilized to measure the performance of nTIM samples, and more importantly, to correlate performance to the controllable parameters. In this paper, we describe our material structures and the myriad permutations of parameters that have been investigated in their design. We report these nTIM thermal performance results, which include a best to-date thermal interface resistance measurement of 3.5 mm2 K/W, independent of applied pressure. This value is significantly better than a variety of commercially available, high-performance thermal pads and greases we tested, and compares favorably with the best results reported for CNT-based materials in an application-representative setting.

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 Expanded Graphite/Paraffin/Silicone Rubber as High Temperature Form-stabilized Phase Change Materials for Thermal Energy Storage and Thermal Interface Materials

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 894 ◽  
Author(s):  
Yafang Zhang ◽  
Wang Li ◽  
Juhua Huang ◽  
Ming Cao ◽  
Guoping Du
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Latent Heat ◽  
Silicone Rubber ◽  
Phase Change Materials ◽  
Expanded Graphite ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Excellent Thermal Stability ◽  
Interface Materials

In this work, expanded graphite/paraffin/silicone rubber composite phase-change materials (PCMs) were prepared by blending the expanded graphite (EG), paraffin wax (PW) and silicone rubber (SR) matrix. It has been shown that PW fully penetrates into the three dimensional (3D) pores of EG to form the EG/PW particles, which are sealed by SR and evenly embedded in the SR matrix. As a result of the excellent thermal stability of SR and the capillary force from the 3D pores of EG, the EG/PW/SR PCMs are found to have good shape stability and high reliability. After being baked in an oven at 150 °C for 24 h, the shape of the EG/PW/SR PCMs is virtually unchanged, and their weight loss and latent heat drop are only 7.91 wt % and 11.3 J/g, respectively. The latent heat of the EG/PW/SR composites can reach up to 43.6 and 41.8 J/g for the melting and crystallizing processes, respectively. The super cooling of PW decreased from 4.2 to 2.4 due to the heterogeneous nucleation on the large surface of EG and the sealing effect of the SR. Meanwhile, the thermal conductivity of the EG/PW/SR PCMs reaches 0.56 W·m−1·K−1, which is about 2.8 times and 3.73 times of pure PW and pristine SR, respectively. The novel EG/PW/SR PCMs with superior shape and thermal stabilities will have a potential application in heat energy storage and thermal interface materials (TIM) for electronic devices.

Silicone Phase Change Thermal Interface Materials: Properties and Applications

2003 ◽  
Author(s):  
S. Mark Zhang ◽  
Diane Swarthout ◽  
Thomas Noll ◽  
Susan Gelderbloom ◽  
Douglas Houtman ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Mechanical Strength ◽  
Phase Change ◽  
Bond Line ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Interface Materials ◽  
Change Material ◽  
Aluminum Mesh

Thermal interface materials (TIM) play a very important role in effectively dissipating unwanted heat generated in electronic devices. This requires that the TIM should have a high bulk thermal conductivity, intimate contact with the substrate surfaces, and the capability to form a thin bond line. In designing new TIMs to meet these industry needs, alkyl methyl siloxane (AMS) waxes have been studied as phase change matrices. AMS waxes are synthesized by grafting long chain alpha-olefins on siloxane polymers. The melting point range of the silicone wax is determined by the hydrocarbon chain length and the siloxane structure. When the AMS wax is mixed with thermally conductive fillers such as alumina, a phase change compound is created. The bulk thermal conductivities of the phase change material (PCM) are reduced as they go through the phase change transition from solid to liquid. By coating the PCM onto an aluminum mesh, both the mechanical strength and the thermal conductivity are drastically improved. The thermal conductivity increases from 4.5 W/mK for the PCM without aluminum support to 7.5 W/mK with the supporting mesh. The thermal resistance of the aluminum-supported sheet at a bond line thickness of 115 microns has been found to be ∼0.24 cm2-C/W. Applying pressure at the time of application has a positive effect on the thermal performance of the PCM. Between contact pressures of 5–80 psi, the thermal resistance decreases as the pressure increases. The weak mechanical strength of the phase change material turns out to be a benefit when ease of rework and the effects of shock and vibration during shipping and handling are considered. A stud pull test of the aluminum mesh-supported PCM shows an average of 13 psi stress at the peak of the break.

Measurement of High-Performance Thermal Interfaces Using a Reduced Scale Steady-State Tester and Infrared Microscopy

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Andrew N. Smith ◽  
Nicholas R. Jankowski ◽  
Lauren M. Boteler
Keyword(s):  
Steady State ◽  
High Performance ◽  
Thermal Interface Materials ◽  
Interfacial Resistance ◽  
Heat Meter ◽  
Thermal Interface ◽  
Order Of Magnitude ◽  
Interface Materials ◽  
Reduced Scale ◽  
Magnitude Improvement

Thermal interface materials (TIMs) have reached values approaching the measurement uncertainty of standard ASTM D5470 based testers of approximately ±1 × 10−6 m2 K/W. This paper presents a miniature ASTM-type steady-state tester that was developed to address the resolution limits of standard testers by reducing the heat meter bar thickness and using infrared (IR) thermography to measure the temperature gradient along the heat meter bar. Thermal interfacial resistance measurements on the order of 1 × 10−6 m2 K/W with an order of magnitude improvement in the uncertainty of ±1 × 10−7 m2 K/W are demonstrated. These measurements were made on several TIMs with a thermal resistance as low as 1.14 × 10−6 m2 K/W.

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