Thermal Performance of Different Carbonaceous Nanoparticles as Additives to Thermal Paste as an Interface Material

2021 ◽  
Author(s):  
Bharath Bharadwaj ◽  
Prashant Singh ◽  
Roop L. Mahajan
Keyword(s):  
Thermal Performance ◽  
Heat Dissipation ◽  
High Conductivity ◽  
The Other ◽  
Multilayer Graphene ◽  
Optimum Level ◽  
Thermal Paste ◽  
Nano Additives ◽  
Thermal Pastes ◽  
Interface Materials

Abstract With increased focus on miniature high power density electronic packages, there is a need for the development of new interface materials with lower thermal resistance. To this end, high conductivity thermal paste or similar thermal interface materials (TIMs), reinforced with superior thermal conductivity materials such as multi-walled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), graphite-derived multilayer graphene (g-MLG) offer an effective strategy to provide efficient paths for heat dissipation from heat source to heat sink. In an earlier paper, we had demonstrated that multilayer graphene derived from coal (coal-MLG) synthesized using our in-house developed one-pot process, has increased presence of phenolic groups on its surfaces, which translates into better dispersion of coal-MLG in silicone thermal paste. In this paper, we first compare the thermal conductance of a high conductivity thermal paste (k = 8.9 W/mK) using coal-MLG as an additive with that realized with other nano additives — MWCNTs, GNPs, and g-MLG. The data shows that coal-MLG as an additive outperforms all the other investigated nano additives in enhancing the thermal performance of the paste. With the coal-MLG as an additive, ∼70% increase in thermal performance was observed as compared to the base thermal paste used. This increase is about 2.5 times higher than that obtained using g-MLG as an additive. We also measured the thermal performance of coal-MLG-based TIM with its different wt.% fractions. The data confirmed our hypothesis that the optimum level of the loading fraction of the additive that can be dispersed in the matrix (paste in this case) before the onset of agglomeration is higher for the coal-MLG (3%) than for the other additives (2%). The implication is further improvement thermal performance with coal-MLG. The data shows the additional thermal enhancement to ∼2X. Finally, since coal-MLG produced by our in-house process is relatively cheaper and more environmentally friendly, we believe that these results would pave the path for enhanced thermal performance with non-silicone thermal pastes at a significantly lower cost. We also expect similar benefits for the silicone-based thermal pastes.

Comparison of Carbon-based Nanostructures with Commercial Products as Thermal Interface Materials

2009 ◽  
Vol 1158 ◽  
Author(s):  
Michael Rosshirt ◽  
Drazen Fabris ◽  
Christopher Cardenas ◽  
Patrick Wilhite ◽  
Thanh Tu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Performance ◽  
Heat Dissipation ◽  
Limiting Factors ◽  
Great Promise ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Commercial Products ◽  
Experimental Findings ◽  
Interface Materials

AbstractHeat dissipation in electronics packaging can be highly dependent on Thermal Interface Materials (TIM). TIM contact, compliance, and conductivity can be the dominant limiting factors in the overall conduction heat transfer across the interface. Mixing multiwall Carbon Nanotubes (CNTs), which have high thermal conductivity, with other thermally conducting materials holds great promise as TIM fillers and has been shown to have higher thermal performance than commercial TIM ‘1’. Such mixtures possess greater thermal conductivity as a result of increased thermal conduction paths through highly conductive, high aspect ratio CNTs.In this work, we develop and test an advanced apparatus based on the ASTM D5470-06 standard to measure thermal interface resistance. Our experimental findings quantify the thermal performance trends of industry-standard TIM Arctic Silver® 5 along with hybrid TIM mixtures of Arctic Silver®5 and varying weight ratios of CNTs. Early experimental findings show that Arctic Silver®5 mixed with 0.5 to 1% multiwall CNT by weight may improve thermal conductivity over pure Arctic Silver®5.The goal of this research is to investigate the viability of integrating CNTs with commercial products as improved TIM for electronic cooling in chip packages.

Electromagnetic Profiling for Groundwater in Precambrian Basement Complex Areas of Nigeria

1990 ◽  
Vol 21 (3) ◽  
pp. 205-216 ◽  
Author(s):  
A. Idowu Olayinka
Keyword(s):  
Water Supply ◽  
Complex Terrain ◽  
High Conductivity ◽  
The Other ◽  
Precambrian Basement ◽  
Basement Complex ◽  
Rural Water Supply ◽  
Well Yield ◽  
Rural Water ◽  
Borehole Drilling

Ground electromagnetic profiling, using a Geonics EM34-3 instrument, has been employed to identify areas of high conductivity in a Precambrian basement complex terrain of Nigeria. Field examples, conducted as part of a rural water supply programme, are presented. They indicate that the apparent conductivities are generally lower than about 60 mmho m−1. Subsequent borehole drilling suggests a good correlation between high EM34 anomalies, deep weathering and high well yield (> 1 1 s−1). On the other hand, boreholes sited on conductivity lows penetrated a thinner regolith with relatively lower yields.

Maximizing Heat Transfer Through Joint Fin Systems

2005 ◽  
Vol 128 (2) ◽  
pp. 203-206 ◽  
Author(s):  
A.-R. A. Khaled
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Performance ◽  
Critical Length ◽  
The Other ◽  
Rigid Fixation ◽  
Convection Coefficient ◽  
Heat Transfer Characteristics ◽  
Cold Side ◽  
Transfer Characteristics

Heat transfer through joint fins is modeled and analyzed analytically in this work. The terminology “joint fin systems” is used to refer to extending surfaces that are exposed to two different convective media from its both ends. It is found that heat transfer through joint fins is maximized at certain critical lengths of each portion (the receiver fin portion which faces the hot side and the sender fin portion that faces the cold side of the convective media). The critical length of each portion of joint fins is increased as the convection coefficient of the other fin portion increases. At a certain value of the thermal conductivity of the sender fin portion, the critical length for the receiver fin portion may be reduced while heat transfer is maximized. This value depends on the convection coefficient for both fin portions. Thermal performance of joint fins is increased as both thermal conductivity of the sender fin portion or its convection coefficient increases. This work shows that the design of machine components such as bolts, screws, and others can be improved to achieve favorable heat transfer characteristics in addition to its main functions such as rigid fixation properties.

scholarly journals Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger

2021 ◽  
Vol 11 (6) ◽  
pp. 2772
Author(s):  
Bin Li ◽  
Zhiheng Zeng ◽  
Xuefeng Zhang ◽  
Ye Zhang
Keyword(s):  
Adaptive Control ◽  
Energy Consumption ◽  
Heat Loss ◽  
Thermal Performance ◽  
Variable Temperature ◽  
The Other ◽  
Drying Process ◽  
Drying Kinetic ◽  
Drying System ◽  
Self Adaptive

To realize energy-saving and efficient industrial grain drying, the present work studied the variable-temperature drying process of corn drying in a novel industrial corn-drying system with a heat recycling and self-adaptive control function. The drying kinetics, thermal performance, heat-loss characteristics and the heat-recycling performance of the drying system under different allocations between flue gas and hot air were investigated, and the optimized drying process was proposed and compared with two constant drying processes. The results showed that the optimized drying process exhibited better drying kinetic and thermal performance than the two constant drying processes. More specifically, the total heat loss, total energy consumption and specific energy consumption of the optimized drying process were ascertained to be 36,132.85 MJ, 48,803.99 MJ and 7290.27 kJ/kg, respectively, which were lower than those of the other two processes. On the other hand, the thermal efficiency of the drying chamber for the optimized drying process was ascertained to be varied within the range of 6.81–41.71%. Overall, the validation results showed that the optimized drying process can significantly improve the drying performance of the drying system.

Characterizing Bulk Thermal Conductivity and Interface Contact Resistance Effects of Thermal Interface Materials in Electronic Cooling Applications

2003 ◽  
Author(s):  
Vadim Gektin ◽  
Sai Ankireddi ◽  
Jim Jones ◽  
Stan Pecavar ◽  
Paul Hundt
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Thermal Performance ◽  
Electronic Cooling ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Interface Contact ◽  
Interface Materials ◽  
Bulk Thermal Conductivity

Thermal Interface Materials (TIMs) are used as thermally conducting media to carry away the heat dissipated by an energy source (e.g. active circuitry on a silicon die). Thermal properties of these interface materials, specified on vendor datasheets, are obtained under conditions that rarely, if at all, represent real life environment. As such, they do not accurately portray the material thermal performance during a field operation. Furthermore, a thermal engineer has no a priori knowledge of how large, in addition to the bulk thermal resistance, the interface contact resistances are, and, hence, how much each influences the cooling strategy. In view of these issues, there exists a need for these materials/interfaces to be characterized experimentally through a series of controlled tests before starting on a thermal design. In this study we present one such characterization for a candidate thermal interface material used in an electronic cooling application. In a controlled test environment, package junction-to-case, Rjc, resistance measurements were obtained for various bondline thicknesses (BLTs) of an interface material over a range of die sizes. These measurements were then curve-fitted to obtain numerical models for the measured thermal resistance for a given die size. Based on the BLT and the associated thermal resistance, the bulk thermal conductivity of the TIM and the interface contact resistance were determined, using the approach described in the paper. The results of this study permit sensitivity analyses of BLT and its effect on thermal performance for future applications, and provide the ability to extrapolate the results obtained for the given die size to a different die size. The suggested methodology presents a readily adaptable approach for the characterization of TIMs and interface/contact resistances in the industry.

Changes in Volatile Compounds during Ripening in Grapes of Airén, Macabeo and Chardonnay White Varieties Grown in La Mancha Region (Spain)

2003 ◽  
Vol 9 (1) ◽  
pp. 33-41 ◽  
Author(s):  
E. García ◽  
J. L. Chacón ◽  
J. Martínez ◽  
P. M. Izquierdo
Keyword(s):  
Volatile Compounds ◽  
Benzyl Alcohol ◽  
Volatile Compound ◽  
The Other ◽  
Optimum Level ◽  
Grape Variety ◽  
La Mancha ◽  
Low Concentrations

Changes in volatile compounds in musts and skins of grapes of Airén, Macabeo and Chardonnay white varieties were determined during ripening. The musts of the Airén variety contained higher concentrations of c-3-hexenol; musts of the Macabeo variety were the richest in t-3-hexenol and 2,4-hexadienal, while the Chardonnay musts stood out for having higher concentrations of benzaldehyde, phenylacetaldehyde and benzyl alcohol. The skins of the three varieties were both qualitatively and quantitatively richer in volatiles than were the musts. The skins of the Airén grapes had the highest levels of nerol. Airén grapes were the only variety in which citronellol was present in the skins. Low concentrations of eugenol were detected in the skins of the Chardonnay grape variety but were not present in the other two varieties. Changes in the concentration of the volatile compounds during ripening were not uniform; this made difficult the determination of the optimum level of ripening for each variety on the basis of the volatile compound content. Nevertheless, results indicated that C6 compounds and terpene concentrations reached a maximum at 6-8 ° Baumé in the Airén grapes and at around 11 ° Baumé in the Chardonnay and Macabeo grapes.

Mechanical Insertion and Reliability Testing of Thermal Interface Materials for Semiconductor Test and Burn-in Applications

2018 ◽  
Vol 2018 (1) ◽  
pp. 000613-000618
Author(s):  
Dave Saums ◽  
Tim Jensen ◽  
Carol Gowans ◽  
Seth Homer ◽  
Ron Hunadi
Keyword(s):  
Thermal Performance ◽  
Mechanical Performance ◽  
Device Under Test ◽  
Thermal Interface Materials ◽  
Reliability Testing ◽  
Mechanical Reliability ◽  
Thermal Interface ◽  
Cycling Test ◽  
Semiconductor Test ◽  
Interface Materials

Abstract Semiconductor test and burn-in requirements for thermal interface materials (TIMs) are challenging, with difficult mechanical reliability requirements that are not found in other types of applications for these materials. To demonstrate the ability of certain newly-developed TIMs to not only provide suitable thermal performance for the device under test and meet these mechanical requirements, a contact cycling test has been devised in three phases for evaluating TIM mechanical performance and durability.

Thermal and Mechanical Properties of Silicone Thermal Interface Materials With Varying Cross-Link Densities

2005 ◽  
Author(s):  
Arun Gowda ◽  
Annita Zhong ◽  
Sandeep Tonapi ◽  
Kaustubh Nagarkar ◽  
K. Srihari
Keyword(s):  
Mechanical Properties ◽  
Thermal Performance ◽  
Cross Linking ◽  
Thermal Interface Materials ◽  
Material System ◽  
Thermal And Mechanical Properties ◽  
Thermal Impedance ◽  
Operating Life ◽  
Thermal Interface ◽  
Interface Materials

Thermal Interface Materials (TIMs) play a key role in the thermal management of microelectronics by providing a path of low thermal impedance between the heat generating devices and the heat dissipating components (heat spreader/sink). In addition, TIMs need to reliably maintain this low thermal resistance path throughout the operating life of the device. Currently, several different TIM material solutions are employed to dissipate heat away from semiconductor devices. Thermal greases, adhesives, gels, pads, and phase change materials are among these material solutions. Each material system has its own advantages and associated application space. While thermal greases offer excellent thermal performance, their uncured state makes them susceptible to pump-out and other degradation mechanisms. On the other hand, adhesives offer structural support but offer a higher heat resistance path. Gels are designed to provide a level of cross-linking to allow the thermal performance of greases and prevent premature degradation. However, the degree of crosslinking can have a significant effect of the behavior of gels. In this research, TIMs with varying cross-linking densities are studied and their thermal and mechanical properties reported. The base resin systems and fillers were maintained constant, while slight compositional alternations were made to induce different degrees of cross-linking.

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