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High-Efficient Production of Boron Nitride Nanosheets via an Optimized Ball Milling Process for Lubrication in Oil

View Article: PubMed Central - PubMed

ABSTRACT

Although tailored wet ball milling can be an efficient method to produce a large quantity of two-dimensional nanomaterials, such as boron nitride (BN) nanosheets, milling parameters including milling speed, ball-to-powder ratio, milling ball size and milling agent, are important for optimization of exfoliation efficiency and production yield. In this report, we systematically investigate the effects of different milling parameters on the production of BN nanosheets with benzyl benzoate being used as the milling agent. It is found that small balls of 0.1–0.2 mm in diameter are much more effective in exfoliating BN particles to BN nanosheets. Under the optimum condition, the production yield can be as high as 13.8% and the BN nanosheets are 0.5–1.5 μm in diameter and a few nanometers thick and of relative high crystallinity and chemical purity. The lubrication properties of the BN nanosheets in base oil have also been studied. The tribological tests show that the BN nanosheets can greatly reduce the friction coefficient and wear scar diameter of the base oil.

No MeSH data available.


SEM image of the sample ball milled at 600 rpm; (b) normalized XRD spectra of the initial hBN particles and the nanosheets ball milled at different milling speeds without centrifugation.
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f3: SEM image of the sample ball milled at 600 rpm; (b) normalized XRD spectra of the initial hBN particles and the nanosheets ball milled at different milling speeds without centrifugation.

Mentions: Milling speed is another important parameter. The milling speed was reduced to 600 rpm with the above optimized conditions (milling time of 10 h and ball-to-powder ratio of 10:1). The amount of BN nanosheets produced at 600 rpm is close to that produced at 800 rpm, but the 600 rpm produced sheets are thicker and larger in size (Fig. 3a) due to the smaller shear force created by the balls and hence less exfoliation. The XRD characterization (Figure 3b) reveals that the intensities of (004) and (006) peaks decrease with the increase of milling speed, suggesting more change to the c-direction of the BN crystal and therefore more thickness reduction. In addition, the (100), (101) and (102) peaks are still visible after 600 rpm milling whereas these peaks disappear for the sample milled at 800 rpm. This indicates that the 600 rpm milled sheets have a smaller size-to-thickness ratio and hence less effective exfoliation.


High-Efficient Production of Boron Nitride Nanosheets via an Optimized Ball Milling Process for Lubrication in Oil
SEM image of the sample ball milled at 600 rpm; (b) normalized XRD spectra of the initial hBN particles and the nanosheets ball milled at different milling speeds without centrifugation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384281&req=5

f3: SEM image of the sample ball milled at 600 rpm; (b) normalized XRD spectra of the initial hBN particles and the nanosheets ball milled at different milling speeds without centrifugation.
Mentions: Milling speed is another important parameter. The milling speed was reduced to 600 rpm with the above optimized conditions (milling time of 10 h and ball-to-powder ratio of 10:1). The amount of BN nanosheets produced at 600 rpm is close to that produced at 800 rpm, but the 600 rpm produced sheets are thicker and larger in size (Fig. 3a) due to the smaller shear force created by the balls and hence less exfoliation. The XRD characterization (Figure 3b) reveals that the intensities of (004) and (006) peaks decrease with the increase of milling speed, suggesting more change to the c-direction of the BN crystal and therefore more thickness reduction. In addition, the (100), (101) and (102) peaks are still visible after 600 rpm milling whereas these peaks disappear for the sample milled at 800 rpm. This indicates that the 600 rpm milled sheets have a smaller size-to-thickness ratio and hence less effective exfoliation.

View Article: PubMed Central - PubMed

ABSTRACT

Although tailored wet ball milling can be an efficient method to produce a large quantity of two-dimensional nanomaterials, such as boron nitride (BN) nanosheets, milling parameters including milling speed, ball-to-powder ratio, milling ball size and milling agent, are important for optimization of exfoliation efficiency and production yield. In this report, we systematically investigate the effects of different milling parameters on the production of BN nanosheets with benzyl benzoate being used as the milling agent. It is found that small balls of 0.1–0.2 mm in diameter are much more effective in exfoliating BN particles to BN nanosheets. Under the optimum condition, the production yield can be as high as 13.8% and the BN nanosheets are 0.5–1.5 μm in diameter and a few nanometers thick and of relative high crystallinity and chemical purity. The lubrication properties of the BN nanosheets in base oil have also been studied. The tribological tests show that the BN nanosheets can greatly reduce the friction coefficient and wear scar diameter of the base oil.

No MeSH data available.