Abstract
In this research, the effect of multi-walled carbon nanotubes (MWCNTs) on the alumina/chromia (Al2O3/Cr2O3) nanocomposites has been investigated. Al2O3/Cr2O3-MWCNTs nanocomposites with variable contents of Cr2O3 and MWCNTs were fabricated using coprecipitation process and followed by spark plasma sintering. XRD analysis revealed a good crystallinity of sintered nanocomposites samples and there was only one phase presence of Al2O3-Cr2O3 solid solution. Density, Vickers microhardness, fracture toughness and fracture strength have been measured in the sintered samples. The results show that the relative density, microhardness and fracture strength of nanocomposites are significantly improved at low contents of Cr2O3 and MWCNTs. The increase of MWCNT’s content in the nanocomposites has adversely affected due to increasing the tangle and interaction of MWCNTs with each other, which leads to agglomeration in the nanocomposites. Increasing of Cr2O3 content in nanocomposites increases formation of Al2O3-Cr2O3 solid solution that actually requires the high sintering temperature to achieve good densification. The fracture toughness of Al2O3/Cr2O3-MWCNTs nanocomposites was enhanced by increasing the carbon nanotube content.
Highlights
IntroductionThe field of the nanocomposite materials has taken a lot of interesting and close observation of engineers and scientists in recent years [1]
The field of the nanocomposite materials has taken a lot of interesting and close observation of engineers and scientists in recent years [1].Nanocomposite materials can be considered of solid structures with nanometer scale dimensional repeat distances between the various phases that constitute the structure
X-ray diffraction patterns for sintered Al2O310 wt% Cr2O3 nanocomposite with different multi-walled carbon nanotubes (MWCNTs) content (0 and 3) wt% are chosen in this test as shown in Fig. 3-a and -b respectively
Summary
The field of the nanocomposite materials has taken a lot of interesting and close observation of engineers and scientists in recent years [1]. Al2O3 and Cr2O3 are the stable sesquioxides having the same corundum crystal structure (hexagonal system with the Al3+ and Cr3+ ions taking two thirds of the octahedral interstitial sites) At high temperature, they form complete substitutional solid solution without consistence of any eutectic over the entire composition range [3,5]. Ahmad et al [10] studied the influence of the carbon nanotubes content on the mechanical properties of Al2O3 that fabricated by hot-pressing They reported a 32% increase in fracture toughness and 12% increase in hardness were observed with 2 wt% of CNTs additive, when compared with the monolithic Al2O3. Siegel et al [11] reported a 24% increase in fracture toughness of Al2O3 with additions of 10 vol% MWCNTs. The present work aims to study the effect of various amounts of multi-walled carbon nanotubes on the some mechanical properties of Al2O3/Cr2O3 nanocomposites. Al2O3/Cr2O3-MWCNTs nanocomposites as a function of the MWCNTs and Cr2O3 contents are investigated
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