Thermal grease

About: Thermal grease is a(n) research topic. Over the lifetime, 2143 publication(s) have been published within this topic receiving 30063 citation(s).

Graphene–Multilayer Graphene Nanocomposites as Highly Efficient Thermal Interface Materials

Abstract: We found that the optimized mixture of graphene and multilayer graphene, produced by the high-yield inexpensive liquid-phase-exfoliation technique, can lead to an extremely strong enhancement of the cross-plane thermal conductivity K of the composite. The “laser flash” measurements revealed a record-high enhancement of K by 2300% in the graphene-based polymer at the filler loading fraction f = 10 vol %. It was determined that the relatively high concentration of the single-layer and bilayer graphene flakes (∼10–15%) present simultaneously with the thicker multilayers of large lateral size (∼1 μm) were essential for the observed unusual K enhancement. The thermal conductivity of the commercial thermal grease was increased from an initial value of ∼5.8 W/mK to K = 14 W/mK at the small loading f = 2%, which preserved all mechanical properties of the hybrid. Our modeling results suggest that graphene–multilayer graphene nanocomposite used as the thermal interface material outperforms those with carbon nanotub...

Graphene -- Based Nanocomposites as Highly Efficient Thermal Interface Materials

Abstract: We found that an optimized mixture of graphene and multilayer graphene - produced by the high-yield inexpensive liquid-phase-exfoliation technique - can lead to an extremely strong enhancement of the cross-plane thermal conductivity K of the composite. The "laser flash" measurements revealed a record-high enhancement of K by 2300 % in the graphene-based polymer at the filler loading fraction f =10 vol. %. It was determined that a relatively high concentration of single-layer and bilayer graphene flakes (~10-15%) present simultaneously with thicker multilayers of large lateral size (~ 1 micrometer) were essential for the observed unusual K enhancement. The thermal conductivity of a commercial thermal grease was increased from an initial value of ~5.8 W/mK to K=14 W/mK at the small loading f=2%, which preserved all mechanical properties of the hybrid. Our modeling results suggest that graphene - multilayer graphene nanocomposite used as the thermal interface material outperforms those with carbon nanotubes or metal nanoparticles owing to graphene's aspect ratio and lower Kapitza resistance at the graphene - matrix interface.

Enhancement of thermal interface materials with carbon nanotube arrays

Abstract: This paper describes an experimental study of thermal contact conductance enhancement enabled by carbon nanotube (CNT) arrays synthesized directly on silicon wafers using plasma-enhanced chemical vapor deposition. Testing based on the one-dimensional reference bar method occurred in a high-vacuum environment with radiation shielding, and temperature measurements were made with an infrared camera. Results from other thermal interface materials are presented, as well as combinations of these materials with CNT arrays. Dry CNT arrays produce a minimum thermal interface resistance of 19.8 mm2 K/W, while the combination of a CNT array and a phase change material produces a minimum resistance of 5.2 mm2 K/W.

Performance and testing of thermal interface materials

Abstract: The increasing power and reduced die size of CPUs used in computers increases a need for significantly improved thermal interface materials (TIM). The TIM is used to reduce contact resistance at the CPU–heat sink interface. This work provides a state-of-the-art assessment on ‘thermal interface materials’, including fundamentals, materials used, their performance, and how interface resistance is measured. The performance of new commercial interface materials is given, as well as discussion of the advantages and disadvantages of different materials. The report notes that the recommended interface test method does not necessarily duplicate the installation and operating conditions in an actual computer installation. Recommendations are presented on the design and operation of an apparatus intended to simulate actual computer installation conditions. The innovative Penn State ‘low melting point alloy’ thermal interface material is described and compared to other commercial materials.

Thermal conductivity of simple and tubular nanowire composites in the longitudinal direction

Abstract: This work establishes a generic model to study phonon transport and the thermal conductivity of periodic two-dimensional nanocomposites in the longitudinal direction (along the wire axis direction) More specifically, the generic model is applied to study the thermal conductivity of silicon-germanium composites with simple silicon nanowire and tubular silicon nanowire inclusions in a germanium matrix, and cylindrical nanoporous silicon materials The results show that the effective thermal conductivity changes not only with the volumetric fraction of the constituents but also with the radius of the nanowires and cylindrical pores due to the nature of the ballistic phonon transport The smaller the wire/pore diameter, the smaller is the thermal conductivity of the periodic two-dimensional nanocomposites for a given volumetric fraction Composites with tubular nanowire inclusions have a lower effective thermal conductivity than simple nanowire composites due to the introduction of additional surface scattering through the pores associated with tubular nanowires Results of this study can be used to direct the development of both high-efficiency thermoelectric materials and thermal interface material containing high-thermal-conductivity particle or wire inclusions