scholarly journals The effects of Fe and NH4Cl on silicon nitridation

2020 ◽  
Author(s):  
X.M. Yi ◽  
Senjing Zhang ◽  
Weijun Zhu ◽  
Qingda Li ◽  
Wenjie Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
Phase Content ◽  
Vapor Liquid Solid ◽  
Α Phase ◽  
Fe Powder ◽  
Powder Content ◽  
Floating Particles ◽  
Silicon Nitridation

Abstract Silicon nitride (Si3N4) with a high α-phase content is in demand due to its higher thermal conductivity for use in heat dissipation bases for electronic devices. However, more needs to be understood about its fibrous growth, therefore, rich fibrous morphologies were synthesized with the assistance of Fe powder and NH4Cl. The effects of these additives on the phase content and fiber morphologies of the products were investigated The results illustrate that the Si3N4 products possess upper and lower layers and that when the Fe powder content is 4 wt% and NH4Cl content is 5 wt%, the Si3N4 fibers have smooth surfaces, uniform diameters, and no floating particles. Moreover, the maximum α-Si3N4 content reached 94.8 wt%, demonstrating an increase in this phase. The double mechanisms of vapor-liquid-solid and vapor-solid are presented as the growth mechanism at the fiber.

scholarly journals Enhanced thermal conductivity of graphene nanoplatelets epoxy composites

2017 ◽  
Vol 35 (2) ◽  
pp. 382-389 ◽  
Author(s):  
Lukasz Jarosinski ◽  
Andrzej Rybak ◽  
Karolina Gaska ◽  
Grzegorz Kmita ◽  
Renata Porebska ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
Graphene Nanoplatelets ◽  
Electrical Insulation ◽  
Graphene Nanocomposites ◽  
Thermally Conductive ◽  
Conductive Particles ◽  
Proper Performance ◽  
Enhanced Thermal Conductivity

Abstract Efficient heat dissipation from modern electronic devices is a key issue for their proper performance. An important role in the assembly of electronic devices is played by polymers, due to their simple application and easiness of processing. The thermal conductivity of pure polymers is relatively low and addition of thermally conductive particles into polymer matrix is the method to enhance the overall thermal conductivity of the composite. The aim of the presented work is to examine a possibility of increasing the thermal conductivity of the filled epoxy resin systems, applicable for electrical insulation, by the use of composites filled with graphene nanoplatelets. It is remarkable that the addition of only 4 wt.% of graphene could lead to 132 % increase in thermal conductivity. In this study, several new aspects of graphene composites such as sedimentation effects or temperature dependence of thermal conductivity have been presented. The thermal conductivity results were also compared with the newest model. The obtained results show potential for application of the graphene nanocomposites for electrical insulation with enhanced thermal conductivity. This paper also presents and discusses the unique temperature dependencies of thermal conductivity in a wide temperature range, significant for full understanding thermal transport mechanisms.

scholarly journals Thermal Conductivity Characterization of Thermal Grease Containing Copper Nanopowder

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1893 ◽  
Author(s):  
Haneul Kang ◽  
Hyunji Kim ◽  
Jihye An ◽  
Siyeon Choi ◽  
Jinho Yang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
Internal Heat ◽  
Upward Trend ◽  
Heat Transfer Medium ◽  
Conductive Materials ◽  
Increasing Trend ◽  
Thermal Grease

As electronic devices and mainboards become smaller, the need for thermal conductive materials having excellent internal heat dissipation is increasing. In this study, nano thermal grease was prepared by mixing in copper nanopowder, which is used as a heat transfer medium in thermal grease, which is a kind of thermal conductive material, with silicon oil. In addition, copper powder was mixed with graphene and alumina, respectively, and the thermal conductivity performance was compared. As a result, the thermal conductivity improved by 4.5 W/m·k over the silicon base, and the upward trend of thermal conductivity increased steadily up to 15 vol. %, and the increasing trend decreased after 20 vol. %. In addition, the increased rate of thermal conductivity from 0 to 5 vol. % and 10 to 15 vol. % was the largest.

Enhancement of Thermal Conductivity of Polyvinyl Alcohol Membrane Using Nano-fiber

MRS Advances ◽  
2017 ◽  
Vol 2 (58-59) ◽  
pp. 3651-3656 ◽  
Author(s):  
Xiandong Chen ◽  
Meng An ◽  
Rulei Guo ◽  
Ni Tang ◽  
Zhan Peng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Polyvinyl Alcohol ◽  
Heat Dissipation ◽  
Phonon Scattering ◽  
Electronic Devices ◽  
Electrospinning Process ◽  
Omega Method ◽  
Nano Fiber ◽  
3 Omega ◽  
3 Omega Method

ABSTRACTThe thermal properties of organic membranes attract much attention due to the fact that heat dissipation in electronic devices limits their functionality and reliability. Here, we enhance the thermal conductivity of polyvinyl alcohol (PVA) membrane using nano-fibers fabricated by electrospinning. Measured by the 3-Omega method, the results show that the effective thermal conductivity of the electrospinning membranes (with/without Cu nanoparticles) are as high as 0.7 W/m-K at room temperature which is as twice as the value of thermal conductivity of amorphous spin-coated PVA membrane (0.35 W/m-K). The mechanism of enhancement are that, compared with amorphous membrane, the phonon scattering is attenuated and the crystallinity is improved in the electrospinning process. Our studies bring new insights in designing new kind of membrane with high thermal conductivity.

High thermal conductivity liquid metal pad for heat dissipation in electronic devices

2018 ◽  
Vol 124 (5) ◽  
Author(s):  
Zuoye Lin ◽  
Huiqiang Liu ◽  
Qiuguo Li ◽  
Han Liu ◽  
Sheng Chu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Liquid Metal ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
High Thermal Conductivity

scholarly journals Enhancement of thermal conductivity in polyamide-6/graphene composites via a “bridge effect” of silicon carbide whiskers

RSC Advances ◽  
2017 ◽  
Vol 7 (73) ◽  
pp. 46306-46312 ◽  
Author(s):  
Na Song ◽  
Haidong Pan ◽  
Xingshuang Hou ◽  
Siqi Cui ◽  
Liyi Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Polymer Composite ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
Polyamide 6 ◽  
High Thermal Conductivity ◽  
Silicon Carbide Whiskers ◽  
Plane Direction

It is urgent to manufacture a polymer composite that has high thermal conductivity (especially in the through-plane direction) and mechanical properties simultaneously to meet the heat dissipation requirement of electronic devices.

Thermal Conductivity of Diamond-Containing Grease

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Hung-En Chou ◽  
Shang-Ray Yang ◽  
Sea-Fue Wang ◽  
James C. Sung
Keyword(s):  
Thermal Conductivity ◽  
Heat Dissipation ◽  
Filler Content ◽  
Electronic Devices ◽  
Terminal Group ◽  
Thermal Interface Material ◽  
Particle Sizes ◽  
Thermal Interface ◽  
Thermal Grease ◽  
Single Filler

As a thermal interface material, thermal grease (TG) has been extensively applied to facilitate heat dissipation in electronic devices. Despite the superior thermal conductivity of diamond, researches on diamond-containing TGs remain rare. In this study, four kinds of TGs in which diamond served as essential filler were prepared and hot disk technique was applied to measure their thermal conductivity k(TG). After two unoverlapped particle sizes were selected, the volumetric filler content, terminal group, and viscosity of a polydimethylsiloxane (PDMS) matrix were modified in sequence. Based on the preferred recipe of a single-filler TG, two double-filler TG series were prepared by retaining the large diamonds and replacing the small ones by Al2O3 or ZnO, respectively. Depending on the content, it was found that diamond was not always the best choice for small filler. The highest k(TG), which was 23 times greater than the original k(PDMS), appeared in a ZnO-containing double-filler grease (=3.52 W/mK). The prediction for the maximum attainable thermal conductivity was preliminarily supported.

scholarly journals Effects of initial α-phase content on the electrical, thermal, and mechanical properties of pressureless solid-state sintered SiC ceramics

2021 ◽  
Author(s):  
Rohit MALIK ◽  
Young-Wook Kim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Solid State ◽  
Impurity Content ◽  
Coarse Grained ◽  
Bandgap Energy ◽  
Phase Content ◽  
Thermal And Mechanical Properties ◽  
Sic Ceramics ◽  
Α Phase

Abstract αand β-SiC starting powders of similar particle sizes were used to investigate the effect of initial α-phase content on the electrical, thermal, and mechanical properties of pressureless solid-state sintered (PSS) SiC ceramics with B4C and C. For β-SiC starting powders, a coarse-grained microstructure with elongated platelet grains formed by the 3C to 6H to 4H-SiC phase transformation was obtained. In contrast, α-SiC powders exhibited a fine-grained microstructure with platelet grains. The electrical resistivity decreased by an order of magnitude with increasing initial α-phase content presumably due to (1) an increased 6H-SiC content causing a decrease in bandgap energy and (2) the low soluble impurity content (Fe and V) of the α-SiC powders. The thermal conductivity increased by approximately 32% with increasing initial α-phase content due to (1) an increased 6H-SiC content, which has a higher intrinsic thermal conductivity compared to 4H and (2) the low impurity content of the α-SiC powders. The flexural strength increased by approximately 16% with increasing initial α-phase content due to a decreased flaw size with decreasing grain size. However, the fracture toughness and hardness were insensitive to the change in initial α-phase content.

Effect of Initial Alpha-SiC Content on Thermal Conductivity of Silicon Carbide Ceramics

2014 ◽  
Vol 616 ◽  
pp. 23-26 ◽  
Author(s):  
Kwang Young Lim ◽  
Tae Young Cho ◽  
Young Wook Kim ◽  
Seung Jae Lee
Keyword(s):  
Thermal Conductivity ◽  
Grain Size ◽  
Room Temperature ◽  
Phase Content ◽  
Sic Ceramics ◽  
Α Phase ◽  
Average Grain Size ◽  
Carbide Ceramics ◽  
Equiaxed Grains ◽  
Silicon Carbide Ceramics

By using α-and/or β-SiC powders, the effects of initial α-phase content on the microstructure and thermal properties of the SiC ceramics sintered with Y2O3 and Sc2O3 were investigated. When α-SiC powder was used, the microstructure consisted of large equiaxed grains and small equiaxed grains. The average grain size decreased with increasing α-SiC content in the starting composition. The thermal conductivity decreased with increasing α-SiC content in the starting composition. Such results suggest that the grain growth of SiC ceramics is beneficial in increasing the thermal conductivity of liquid-phase sintered SiC ceramics. The thermal conductivity of SiC ceramics processed from a 90% β-SiC-10% α-SiC powder mixture was 159 W/m∙K at room temperature.

scholarly journals Rheological Properties and Thermal Conductivity of Epoxy Resins Filled with a Mixture of Alumina and Boron Nitride

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 597 ◽  
Author(s):  
Van-Dung Mai ◽  
Dae-Il Lee ◽  
Jun-Hong Park ◽  
Dai-Soo Lee
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Electronic Packaging ◽  
Epoxy Resins ◽  
Heat Dissipation ◽  
Filler Content ◽  
Electronic Devices ◽  
High Thermal Conductivity ◽  
Packaging Materials ◽  
Thermally Conductive

Electronic packaging materials with high thermal conductivity and suitable viscosity are necessary in the manufacturing of highly integrated electronic devices for efficient heat dissipation during operation. This study looked at the effect of boron nitride (BN) platelets on the rheology and thermal conductivity of composites based on alumina (Al2O3) and epoxy resin (EP) for the potential application as electronic packaging. The viscosity and thermal conductivity of the composite were increased upon increasing filler content. Furthermore, thermal conductivity of the BN/Al2O3/EP was much higher than that of Al2O3/EP at almost the same filler loadings. These unique properties resulted from the high thermal conductivity of the BN and the synergistic effect of the spherical and plate shapes of these two fillers. The orientation of BN platelets can be controlled by adjusting their loading to facilitate the formation of higher thermally conductive pathways. The optimal content of the BN in the Al2O3/EP composites was confirmed to be 5.3 vol %, along with the maximum thermal conductivity of 4.4 W/(m·K).

scholarly journals 3D Thermal Network Supported by CF Felt for Improving the Thermal Performance of CF/C/Epoxy Composites

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 980
Author(s):  
Xinfeng Wu ◽  
Yuan Gao ◽  
Tao Jiang ◽  
Lingyu Zheng ◽  
Ying Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electronic Devices ◽  
Epoxy Composites ◽  
Operating Efficiency ◽  
Impregnation Method ◽  
Molding Method ◽  
Needle Punching ◽  
3D Network ◽  
Network Method ◽  
Process Method

The heat generated by a high-power device will seriously affect the operating efficiency and service life of electronic devices, which greatly limits the development of the microelectronic industry. Carbon fiber (CF) materials with excellent thermal conductivity have been favored by scientific researchers. In this paper, CF/carbon felt (CF/C felt) was fabricated by CF and phenolic resin using the “airflow network method”, “needle-punching method” and “graphitization process method”. Then, the CF/C/Epoxy composites (CF/C/EP) were prepared by the CF/C felt and epoxy resin using the “liquid phase impregnation method” and “compression molding method”. The results show that the CF/C felt has a 3D network structure, which is very conducive to improving the thermal conductivity of the CF/C/EP composite. The thermal conductivity of the CF/C/EP composite reaches 3.39 W/mK with 31.2 wt% CF/C, which is about 17 times of that of pure epoxy.

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