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Thermal conductivity enhancement in thermal grease containing different CuO structures.

Yu W, Zhao J, Wang M, Hu Y, Chen L, Xie H - Nanoscale Res Lett (2015)

Bottom Line: The morphologies and crystal structures of these CuO structures are characterized by field-emission scanning electron microscope and X-ray diffractometer, respectively.Compared with pure silicone base, the thermal conductivities of thermal greases with CuO microdisks, CuO nanoblocks, and CuO microspheres are 0.283, 0256, and 0.239 W/mK, respectively, at filler loading of 9 vol.%, which increases 139%, 116%, and 99%, respectively.These experimental data are compared with Nan's model prediction, indicating that the shape factor has a great influence on thermal conductivity improvement of thermal greases with different CuO structures.

View Article: PubMed Central - PubMed

Affiliation: College of Engineering, Shanghai Second Polytechnic University, 2360 Jin Hai Road, Pudong District,, Shanghai, 201209 China.

ABSTRACT
Different cupric oxide (CuO) structures have attracted intensive interest because of their promising applications in various fields. In this study, three kinds of CuO structures, namely, CuO microdisks, CuO nanoblocks, and CuO microspheres, are synthesized by solution-based synthetic methods. The morphologies and crystal structures of these CuO structures are characterized by field-emission scanning electron microscope and X-ray diffractometer, respectively. They are used as thermal conductive fillers to prepare silicone-based thermal greases, giving rise to great enhancement in thermal conductivity. Compared with pure silicone base, the thermal conductivities of thermal greases with CuO microdisks, CuO nanoblocks, and CuO microspheres are 0.283, 0256, and 0.239 W/mK, respectively, at filler loading of 9 vol.%, which increases 139%, 116%, and 99%, respectively. These thermal greases present a slight descendent tendency in thermal conductivity at elevated temperatures. These experimental data are compared with Nan's model prediction, indicating that the shape factor has a great influence on thermal conductivity improvement of thermal greases with different CuO structures. Meanwhile, due to large aspect ratio of CuO microdisks, they can form thermal networks more effectively than the other two structures, resulting in higher thermal conductivity enhancement.

No MeSH data available.


FE-SEM images of different structures. (a) CuO microdisks, (c) CuO nanoblocks, and (e) CuO microspheres at low magnification; (b) CuO microdisks, (d) CuO nanoblocks, and (f) CuO microspheres at high magnification.
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Fig1: FE-SEM images of different structures. (a) CuO microdisks, (c) CuO nanoblocks, and (e) CuO microspheres at low magnification; (b) CuO microdisks, (d) CuO nanoblocks, and (f) CuO microspheres at high magnification.

Mentions: The morphologies of as-synthesized CuO structures were observed by using field-emission scanning electron microscope, shown in Figure 1. Figure 1a is the low-magnification SEM image of as-synthesized CuO structures, confirming that the products are synthesized nearly with same morphology. The synthesized products are round or hexagonal disks of CuO as revealed by the high-magnification SEM image presented in Figure 1b. The average planar sizes of CuO microdisks are in range of 1.0 ~ 1.8 μm. The thicknesses of the CuO microdisks are in range of 50 ~ 100 nm, which is obtained from the analysis of SEM images with right position. Meanwhile, the surfaces of CuO microdisks are not smooth, and some small nanosheets are horizontally deposited on the upper surface of the microdisks, which suggests that the microdisks are formed by the accumulation of CuO nanosheets. Seen from the Figure 1c,d, the as-synthesized CuO structures are nanoblocks with planar size of 200 ~ 350 nm and thickness of 100 ~ 150 nm. The surfaces of the nanoblocks are very smooth. Figure 1e,d shows the FE-SEM images of CuO products at low and high magnification, respectively. The as-synthesized CuO structures are microspheres with diameter of about 1 μm. The surface of the microspheres is rough with some gullies.Figure 1


Thermal conductivity enhancement in thermal grease containing different CuO structures.

Yu W, Zhao J, Wang M, Hu Y, Chen L, Xie H - Nanoscale Res Lett (2015)

FE-SEM images of different structures. (a) CuO microdisks, (c) CuO nanoblocks, and (e) CuO microspheres at low magnification; (b) CuO microdisks, (d) CuO nanoblocks, and (f) CuO microspheres at high magnification.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4385151&req=5

Fig1: FE-SEM images of different structures. (a) CuO microdisks, (c) CuO nanoblocks, and (e) CuO microspheres at low magnification; (b) CuO microdisks, (d) CuO nanoblocks, and (f) CuO microspheres at high magnification.
Mentions: The morphologies of as-synthesized CuO structures were observed by using field-emission scanning electron microscope, shown in Figure 1. Figure 1a is the low-magnification SEM image of as-synthesized CuO structures, confirming that the products are synthesized nearly with same morphology. The synthesized products are round or hexagonal disks of CuO as revealed by the high-magnification SEM image presented in Figure 1b. The average planar sizes of CuO microdisks are in range of 1.0 ~ 1.8 μm. The thicknesses of the CuO microdisks are in range of 50 ~ 100 nm, which is obtained from the analysis of SEM images with right position. Meanwhile, the surfaces of CuO microdisks are not smooth, and some small nanosheets are horizontally deposited on the upper surface of the microdisks, which suggests that the microdisks are formed by the accumulation of CuO nanosheets. Seen from the Figure 1c,d, the as-synthesized CuO structures are nanoblocks with planar size of 200 ~ 350 nm and thickness of 100 ~ 150 nm. The surfaces of the nanoblocks are very smooth. Figure 1e,d shows the FE-SEM images of CuO products at low and high magnification, respectively. The as-synthesized CuO structures are microspheres with diameter of about 1 μm. The surface of the microspheres is rough with some gullies.Figure 1

Bottom Line: The morphologies and crystal structures of these CuO structures are characterized by field-emission scanning electron microscope and X-ray diffractometer, respectively.Compared with pure silicone base, the thermal conductivities of thermal greases with CuO microdisks, CuO nanoblocks, and CuO microspheres are 0.283, 0256, and 0.239 W/mK, respectively, at filler loading of 9 vol.%, which increases 139%, 116%, and 99%, respectively.These experimental data are compared with Nan's model prediction, indicating that the shape factor has a great influence on thermal conductivity improvement of thermal greases with different CuO structures.

View Article: PubMed Central - PubMed

Affiliation: College of Engineering, Shanghai Second Polytechnic University, 2360 Jin Hai Road, Pudong District,, Shanghai, 201209 China.

ABSTRACT
Different cupric oxide (CuO) structures have attracted intensive interest because of their promising applications in various fields. In this study, three kinds of CuO structures, namely, CuO microdisks, CuO nanoblocks, and CuO microspheres, are synthesized by solution-based synthetic methods. The morphologies and crystal structures of these CuO structures are characterized by field-emission scanning electron microscope and X-ray diffractometer, respectively. They are used as thermal conductive fillers to prepare silicone-based thermal greases, giving rise to great enhancement in thermal conductivity. Compared with pure silicone base, the thermal conductivities of thermal greases with CuO microdisks, CuO nanoblocks, and CuO microspheres are 0.283, 0256, and 0.239 W/mK, respectively, at filler loading of 9 vol.%, which increases 139%, 116%, and 99%, respectively. These thermal greases present a slight descendent tendency in thermal conductivity at elevated temperatures. These experimental data are compared with Nan's model prediction, indicating that the shape factor has a great influence on thermal conductivity improvement of thermal greases with different CuO structures. Meanwhile, due to large aspect ratio of CuO microdisks, they can form thermal networks more effectively than the other two structures, resulting in higher thermal conductivity enhancement.

No MeSH data available.