Mechanical and electrical properties of carbon nanotube-reinforced Al2O3 nanocomposites

Guo, Christine; X, Luo; Shah, W.A.; Bin, Huang; Li, J. K.; Umer, Malik Adeel; Yang, Yiwen

doi:10.1007/s10853-019-04173-5

Cited by 16 publications

(2 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further addition of MWCNT from 0.3 wt.% to 0.5 wt.% resulted in declining of density value from 4.140 g/cm 3 , 4.080 g/cm 3 and 4.060 g/cm 3 respectively. This result is parallel to the previous work by Guo and Luo [15], where density value decreases, as the content of CNTs increases. Poor dispersion of MWCNT in the matrix results in agglomeration around alumina grain boundaries.…”

Section: Fig 3: Xrd Results Of Mwcnts Particlesupporting

confidence: 90%

The Effects of MWCNT Addition to Physical Properties of ZTA-MgO Cutting Tool

Hamidon

Manshor

Azhar

et al. 2022

KEM

View full text Add to dashboard Cite

The purpose of this study is to develop ZTA-MgO-MWCNT cutting insert with enhanced properties and excellent tool performance that is suitable for high-speed machining. The effects of MWCNT addition on the physical properties of ZTA-MgO composites were investigated. The samples were fabricated using 80:20 composition (80 wt.% of Al2O3: 20 wt.% of YSZ) with fixed amount of MgO at 1.1 wt.% and MWCNT ranging from (0.1 – 0.5 wt.%) as secondary additives. The CNT was pre-treated in ethanol for 1 hour using an ultrasonic homogenizer before mixing and ball milled with Al2O3, YSZ and MgO compositions for 24 hours. The mixture is then pressed at 100 MPa into round-shaped cutting inserts mold after being dried at 100°C for 24 hours. The pressed samples were sintered at 1600 oC for 4 hour soaking time. XRD, density, porosity and shrinkage analysis performed on the samples. The XRD analyses indicate the presence of major phases were α-Al2O3, ZrO2, Zr0.963Y0.037O1.982 and MgAl2O4. The effect of MWNT addition on density, porosity and shrinkage of ZTA-MgO shows that density (4.210 g/cm3) and percentage of shrinkage (8.05%) obtained the highest value by 0.2 wt.% MWCNT compared with samples without CNT additives which is only 4.020 g/cm3 and 7.05% respectively. High density value indicates that the shrinkage percentage is also high, which corresponds to the densification of the composites. Poor dispersion of MWCNT within the matrix is highly accounted for agglomeration around Al2O3 grain boundaries and decreases in densification.

show abstract

Section: Fig 3: Xrd Results Of Mwcnts Particlesupporting

confidence: 90%

The Effects of MWCNT Addition to Physical Properties of ZTA-MgO Cutting Tool

Hamidon

Manshor

Azhar

et al. 2022

KEM

View full text Add to dashboard Cite

show abstract

“…Out of all available metal oxides, Al 2 O 3 was chosen for three reasons. First, reinforcing Al 2 O 3 with CNTs is widely documented in the literature, with contribution spanning mechanical, − thermal, − and electrical ,− properties. Ahmad et al reported 94% increase in fracture toughness of Al 2 O 3 with 4 vol % of MWCNTs, Kumari et al reported 150% increase in its thermal conductivity with 19.1 wt % of MWCNTs, and Ahmad et al.…”

Section: Introductionmentioning

confidence: 99%

Alumina Thin-Film Deposition on Rough Topographies Comprising Vertically Aligned Carbon Nanotubes: Implications for Membranes, Sensors, and Electrodes

Rovinsky

Barick

Lieberman

et al. 2020

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

In this article, the limits of thin-film deposition on very rough topographies are demonstrated by depositing alumina on vertically aligned carbon nanotubes (VACNTs). Vapor deposition techniques are the enabling platforms of the thin-film industry, offering high material versatility and good coverage ability on relatively flat surfaces, leading to frequent use in a large array of applications, especially nanoscale electronic devices such as sensors and electrodes. However, when surface topography exhibits high roughness, even depositions that are not limited to line-of-sight show only partial coverage, significantly hindering performances. Our manufacturing process of VACNT/Al2O3 nanocomposites has three vaporous steps: CNT growth by chemical vapor deposition (CVD), functionalization via controlled thermal oxidation, and atomic layer deposition (ALD) of alumina. The same limited accessibility hinders each of these three steps. Morphological analyses show different CNT heights throughout the sample, with shorter CNTs in the middle, having less access to gases. As height differences between the center and peripheries escalate, sample centers may collapse under the tension. The limited accessibility of the center is manifested also in inhomogeneous oxygen contents, between sample centers and peripheries. Finally, a sharp transition in deposition quality occurs during the deposition process of Al2O3, from homogeneous to inconsistent, which is also linked to the accessibility differences between. Adjusting process parameters, we have successfully coated 1.8 mm-tall VACNT arrays with a homogeneous thin (few nm) Al2O3 layer and were able to increase the depth at which, thick (few dozens of nm) Al2O3 coating is uniform from 20 to 350 μm. However, when VACNTs were functionalized, the penetration depth was found to correlate negatively with center oxygen content. These results, indicating diffusion as a rate-setting step in complex topography coatings, can significantly improve deposition quality and enhance the performance of thin-film applications such as membranes, sensors, and electrodes for energy harvesting and storage.

show abstract