Thermal and electrical conduction of AL/CNT composite

2021 ◽  
pp. 002199832110370
Author(s):  
Md Muktadir Billah ◽  
Jingyin Jiang ◽  
Nayab Shiraz ◽  
Quanfang Chen

Authors have investigated the thermal and electrical conduction behavior of Al/MWCNT composite fabricated by powder metallurgy method in which CNTs were pre-encapsulated with Ni. The thermal and electrical conductivity values were found proportional to the addition of CNTs. For 2.5% wt. CNTs addition with HIP treatment, the Al/CNT composite showed thermal conductivity of 476 W/m-k which is about 85% higher than the value of pure Al. Also, the resultant electrical conductivity was 0.405 × 10−8 S which is about 14% higher than the value of pure Al. The increased thermal and electrical conductivity can be attributed mainly to the well dispersion of CNTs through Ni-encapsulation and the enhanced interfacial bonding of Ni-coated CNTs with the matrix. Due to having good electrical conductivity of nickel itself, electrical conductivity of the composite was also enhanced which was further confirmed from First Principle study.

2007 ◽  
Vol 1044 ◽  
Author(s):  
Mi-kyung Han ◽  
Huijun Kong ◽  
Ctirad Uher ◽  
Mercouri G Kanatzidis

AbstractWe performed comparative investigations of the Ag1-xPb18MTe20 (M = Bi, Sb) (x = 0, 0.14, 0.3) system to better understand the roles of Sb and Bi on the thermoelectric properties. In both systems, the electrical conductivity nearly keeps the same values, while the Seebeck coefficient decreases dramatically in going from Sb to Bi. Compared to the lattice thermal conductivity of PbTe, that of AgPb18BiTe20 is substantially reduced. The lattice thermal conductivity of the Bi analog, however, is higher than that of AgPb18SbTe20 and this is attributed largely to the decrease in the degree of mass fluctuation between the nanostructures and the matrix (for the Bi analog). As a result the dimensionless figure of merit ZT of Ag1-xPb18MTe20 (M = Bi) is found to be smaller than that of Ag1-xPb18MTe20 (M = Sb).


2015 ◽  
Vol 667 ◽  
pp. 303-307
Author(s):  
Hang Song Yang ◽  
Shao Ju Hao ◽  
Jun Jie Liang

For its light quality, good thermal conductivity, and excellent electricity shielding performance, Magnesium alloy has been used in industry, agricultural and so on, for rare earth elements can improve the mechanical performance of magnesium alloy, the study of powder metallurgy is influence by rare earth magnesium is few at present. so, in this paper, by mixing powder metallurgy method the Y89 element was added in Mg17Al12 magnesium alloy, the influence of Y89 on microstructure, hardness and compression performance of Mg17Al12 magnesium alloy was studied, The experimental results show that when amount of Y89’s addition, the mechanical performance is more then and when is 1.22%, its mechanical performance is best, hardness is 66.7 HV, compressive strength is 113.6 MPa,increased respectively by 19.7% and 29.3% compared the Mg17Al12 magnesium alloy substrate, and the grain refinement effect of Mg17Al12 magnesium alloy is the best at this time.


1989 ◽  
Vol 111 (2) ◽  
pp. 281-286 ◽  
Author(s):  
J. S. Agapiou ◽  
M. F. DeVries

The thermal conductivity of a 304L stainless steel powder metallurgy (P/M) material was experimentally determined to support research aimed at understanding the poor machining characteristics of P/M austenitic stainless steels. Thermal conductivity measurements were made on samples having relative densities ranging between 64 and 90 percent of theoretical density since workpieces requiring machining are often fabricated in that density range. The measurements were also made over a temperature range of 50 to 300°C since workpiece temperatures can attain levels this high during the machining operation. The thermal conductivity was measured using an apparatus having a design based on the comparative method. The experimentally determined thermal conductivities were modeled by mathematical models found in the technical literature and modified for the present study. The thermal conductivity of this material increases with increasing relative density and temperature; it is also dependent on the matrix structure for a given porosity.


Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3671
Author(s):  
Lei Wang ◽  
Jing Wen ◽  
Yuan Jiang ◽  
Qiaofeng Ou ◽  
Lei Yu ◽  
...  

The electronic structure and the corresponding electrical conductive behavior of the Cu/Cr2C/TiN stack were assessed according to a newly developed first-principle model based on density functional theory. Using an additional Cr2C layer provides the metal-like characteristic of the Cu/Cr2C/TiN stack with much larger electrical conduction coefficients (i.e., mobility, diffusivity, and electrical conductivity) than the conventional Ag/Ti3C2/Pt stack due to the lower activation energy. This device is therefore capable of offering faster switching speeds, lower programming voltage, and better stability and durability than the memristor device with conventional Ti3C2 MXene.


MRS Bulletin ◽  
2007 ◽  
Vol 32 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Karen I. Winey ◽  
Takashi Kashiwagi ◽  
Minfang Mu

AbstractThe remarkable electrical and thermal conductivities of isolated carbon nanotubes have spurred worldwide interest in using nanotubes to enhance polymer properties. Electrical conductivity in nanotube/polymer composites is well described by percolation, where the presence of an interconnected nanotube network corresponds to a dramatic increase in electrical conductivity ranging from 10−5 S/cm to 1 S/cm. Given the high aspect ratios and small diameters of carbon nanotubes, percolation thresholds are often reported below 1 wt% although nanotube dispersion and alignment strongly influence this value. Increases in thermal conductivity are modest (∼3 times) because the inter facial thermal re sis tance between nanotubes is considerable and the thermal conductivity of nanotubes is only 104 greater than the polymer, which forces the matrix to contribute more toward the composite thermal conductivity, as compared to the contrast in electrical conductivity, >1014. The nanotube network is also valuable for improving flame-retardant efficiency by producing a protective nanotube residue. In this ar ticle, we highlight published research results that elucidate fundamental structure–property relationships pertaining to electrical, thermal, and/or flammability properties in numerous nanotube-containing polymer composites, so that specific applications can be targeted for future commercial success.


2011 ◽  
Vol 66-68 ◽  
pp. 1390-1396
Author(s):  
Jing Song Zhao ◽  
Yi Feng ◽  
Nan Nan Chen ◽  
Fan Yan Chen ◽  
Jie Chen ◽  
...  

The transmutation target of nuclear waste material has been fabrication by a powder metallurgy method by using Alumina as the matrix and CNTs as reinforcement. The effect of different nanotube contents on the fracture toughness and the bending strength was investigation. The results showed the fracture toughness and the bending strength of composites increased with increasing CNTs mass fraction when the content of CNTs was less than 1.5%. However, when the contents of CNTs greater than 1.5%, the fracture toughness and the bending strength of composites decreased as the content of CNTs increased. Possible mechanisms are discussed in detail in the paper.


2021 ◽  
Author(s):  
Cheng-Lun Hsin ◽  
Jen-Che Hsiao ◽  
You-Ming Chen ◽  
Sheng-Wei Lee

Abstract Thermoelectric materials are considered promising candidates for thermal energy conversion. This study presents the fabrication of Zn– and Ce–alloyed In2O3 with a porous structure. The electrical conductivity was improved by the alloying effect and an ultra–low thermal conductivity was observed owing to the porous structure, which concomitantly provide a distinct enhancement of ZT. However, SiO2 nanoparticle additives react with the matrix to form a third-phase impurity, which weakens the electrical conductivity and increases the thermal conductivity. A thermoelectric module was constructed for the purpose of thermal heat energy conversion. Our experimental results proved that both an enhancement in electrical conductivity and a suppression in thermal conductivity could be achieved through nano–engineering. This approach presents a feasible route to synthesize porous thermoelectric oxides, and provides insight into the effect of additives; moreover, this approach is a cost-effective method for the fabrication of thermoelectric oxides without traditional hot-pressing and spark–plasma–sintering processes.


2011 ◽  
Vol 46 (9) ◽  
pp. 1127-1136 ◽  
Author(s):  
Xuebing Liang ◽  
Chengchang Jia ◽  
Ke Chu ◽  
Hui Chen ◽  
Junhui Nie ◽  
...  

Metal/diamond composites have been considered as the new generation of thermal management material. The critical challenge to obtain composites with high thermal conductivity (TC) is to improve the interfacial bonding between the matrix and diamond. In the present study, a titanium coating was plated on the surface of diamond particles via vacuum evaporation–deposition, and Al/diamond composites were consolidated by spark plasma sintering (SPS) technique. The TC and microstructure of composites, respectively, with coated and uncoated diamond particles are compared and discussed. The results show that the Ti coating can significantly increase the wetting property between Al and diamond, leading to a strong interfacial bonding. The diffusion of Ti into the matrix and the formation of TiC are detected at the Al–diamond interface. The properties of composites, respectively, with coated and uncoated diamond exhibit different trends with increasing sintering temperature or diamond volume fraction. Compared with composites with uncoated particles, the Al/Ti–diamond composites obtained the much higher relative density and TC as high as 491 W/mK. Based on the comparison between the experimental and theoretical values, it is found that the thermal conductivities of Al/Ti–diamond composites have reached or surpassed the theoretical calculations with the particle volume fraction not more than 50%.


2011 ◽  
Vol 471-472 ◽  
pp. 420-425 ◽  
Author(s):  
Mohammad Moazami-Goudarzi ◽  
Farshad Akhlaghi

In the present study the effect of Mg addition on the characteristics of Al/SiC nanocomposite powder particles produced via a relatively new method called in situ powder metallurgy (IPM) is investigated. Commercially pure Al and Al-Mg alloy melts containing different amounts of Mg were used as the matrix alloy. Nano-sized SiC particles with the average size of 60 nm were used as the reinforcing material. The effect of Mg content on the fluidity of the melt as an influencing factor affecting both the process yield and wettability of SiC with molten metal was investigated. The size distribution of produced powders was characterized using a laser particle size analyzer. Scanning electron microscopy was utilized to investigate the possibility of embedding of SiC nanoparticles within the metallic matrix. Results of microhardness measurements together with SEM micrographs and EDS analysis showed that nano-sized SiC particles could be embedded in the relatively coarse Al-Mg powders containing at least 1 wt.% Mg.


2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Ning Li ◽  
Hong Yan ◽  
Qingjie Wu ◽  
Zeyu Cao

AbstractIt can be known from a large number of research results that improving the dispersibility of CNTs can effectively optimize the mechanical properties of the corresponding metal matrix composites. However, the crucial issue of increasing the bonding of CNTs and the matrix is still unsolved. In this paper, a novel method was developed to increase interfacial bonding strength by coating titanium oxide (TiO2) on the surface of CNTs. The rare earth Pr and TiO2@CNTs-reinforced AZ91matrix composites were successfully fabricated by powder metallurgy. Hot press sintering and hot extrusion of the milled powder was performed. After hot extrusion, the influence of TiO2@CNTs on the microstructure and mechanical properties of the composites were investigated. The results showed that the coating process can improve the distribution of CNTs in Mg alloy. The CNTs refined the grains of the matrix, and the CNTs were presented throughout the extrusion direction. When the TiO2@CNTs content was 1.0 wt.%, the yield strength (YS), ultimate tensile strength (UTS), and elongation of the alloy attained maximum values. The values were improved by 23.5%, 82.1%, and 40.0%, respectively, when compared with the AZ91 alloy. Good interfacial bonding was achieved, which resulted in an effective tensile loading transfer at the interface. CNTs carried the tensile stress and were observed on the tensile fracture.


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