Tailoring Thermal Transport Properties by Inducing Surface Oxidation Reactions in Bulk Metal Composites

Shancita, I.; Cagle, Colton; Kalish, Irina; Dubé, Pascal; Abraham, Joseph; Hammond, Bradford; Warzywoda, Juliusz; Pantoya, Michelle L.

doi:10.1021/acsami.1c02792

Cited by 4 publications

(2 citation statements)

References 11 publications

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“…Effective thermal transport behavior in graphene-wrapped Ag composites can be highlighted through thermal diffusivity measurements. 41,42 Although thermal conductivity (κ) is the dominant indicator of thermal transport, thermal diffusivity (α) can be directly related to κ by the following equation:…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Effective thermal transport behavior in graphene-wrapped Ag composites can be highlighted through thermal diffusivity measurements. , Although thermal conductivity (κ) is the dominant indicator of thermal transport, thermal diffusivity (α) can be directly related to κ by the following equation: The direct relationship can be drawn on constant density (ρ) and heat capacity ( C P ). In the case of Ag and graphene-wrapped Ag samples even with differences in graphene contents (Table ), the observed similarities in density and heat capacity makes effective thermal transport to transitively equate to high thermal diffusivity.…”

Section: Resultsmentioning

confidence: 99%

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Enhanced Thermal Conducting Behavior of Pressurized Graphene-Silver Flake Composites

et al. 2022

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Modern electronics continue to shrink down the sizes while becoming more and more powerful. To improve heat dissipation of electronics, fillers used in the semiconductor packaging process need to possess both high electrical and thermal conductivity. Graphene is known to improve thermal conductivity but suffers from van der Waals interactions and thus poor processibility. In this study, we wrapped silver microflakes with graphene sheets, which can enable intercoupling of phonon-and electron-based thermal transport, to improve the thermal conductivity. Using just 1.55 wt % graphene for wrapping can achieve a 2.64-times greater thermal diffusivity (equivalent to 254.196 ± 10.123 W/m•K) over pristine silver flakes. Graphenewrapped silver flakes minimize the increase of electrical resistivity, which is one-order higher (1.4 × 10 −3 Ω•cm) than the pristine flakes (5.7 × 10 −4 Ω•cm). Trace contents of wrapped graphene (<1.55 wt %) were found to be enough to bridge the void between Ag flakes, and this enhances the thermal conductivity. Graphene loading at 3.76 wt % (beyond the threshold of 1.55 wt %) results in the significant graphene aggregation that decreases thermal diffusivity to as low as 16% of the pristine Ag filler. This work recognizes that suitable amounts of graphene wrapping can enhance heat dissipation, but too much graphene results in unwanted aggregation that hinders thermal conducting performance.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Enhanced Thermal Conducting Behavior of Pressurized Graphene-Silver Flake Composites

et al. 2022

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Prediction of absorptivity in Multi-Jet Fusion manufactured polypropylene structures through laser flash and corrected porosity method

Kafi,

Khorasani,

Downing

et al. 2024

Int J Adv Manuf Technol

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For the first time in the literature, this study validates the absorption phenomena in Multi-Jet Fusion (MJF) printed polypropylene (PP) structures through Laser Flash (LFA) and Corrected Porosity (CP) methods. The influence of process parameters such as build height and build orientation was investigated on tensile properties, crystallinity, porosity and thermophysical attributes in MJF printed PP coupons. Results showed that both crystallinity and tensile performance did not significantly vary with either location or build orientation. Interestingly, samples printed in the Z orientation showed a 35% decrease in strain, indicating that Z-oriented MJF coupons were more brittle than the flat samples (XY). Samples printed in Z orientation also possessed higher porosity and relatively lower crystallinity than the XY orientation. However, large deviations within porosity values were an obstacle to determining a suitable build chamber location for manufacturing dense samples. Therefore, a detailed investigation on porosity of printed samples using micro-CT scans and CT image analysis was necessary. Initially, poor contrast was obvious when MJF printed samples were positioned vertically in the micro-CT chamber which was mainly due to high value of horizontal intensity profile (HIP ~ 70%). Contrast in MJF samples improved significantly in the horizontal orientation (HIP ~ 40%). In parallel, the half-time and heat loss were measured in LFA to understand changes in absorption phenomena with height and orientation of the build. A direct correlation was found between LFA half-time and porosity only when the porosity correction method was implemented. Corrected porosity value was found to be inversely proportional to the heat loss of printed PP samples which indicated higher absorption for samples printed in the bottom of build chamber, XY12, whereas lower absorption was observed for less dense Z samples. Finally, heat loss phenomenon was verified using dense reference Pyroceram samples as they possess high diffusivity and low half-time and porosity compared to MJF printed samples. There is a science behind understanding the absorptivity of the MJF process which is related to the complexity of the process and is challenging to address in MJF PP samples when mixed with carbon black. The study showed that accurately determining the level of porosity is the key to validate absorption phenomena within MJF printed coupons. The contributions of this work are the investigation of the light absorption phenomena in MJF printed PP structures, and the establishment of the absorption-porosity correlation. These contributions help to predict the mechanical properties and subsequently the overall quality of the produced parts which can save cost and time in effectively utilising the MJF process.

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In-situ thermal analysis of intermetallic and thermite projectiles in high velocity impact experiments

Woodruff

Dean

Cagle

et al. 2022

International Journal of Heat and Mass Transfer

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Tailoring Thermal Transport Properties by Inducing Surface Oxidation Reactions in Bulk Metal Composites

Cited by 4 publications

References 11 publications

Enhanced Thermal Conducting Behavior of Pressurized Graphene-Silver Flake Composites

Enhanced Thermal Conducting Behavior of Pressurized Graphene-Silver Flake Composites

Prediction of absorptivity in Multi-Jet Fusion manufactured polypropylene structures through laser flash and corrected porosity method

In-situ thermal analysis of intermetallic and thermite projectiles in high velocity impact experiments

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