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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 images for sample ball milled with different ball-to-powder ratio (a) 10:1, (b) 20:1, (c) 50:1 and (d) normalized XRD spectra of the initial hBN particles and the sheets ball milled with different ball-to-powder ratio without centrifugation.
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f2: SEM images for sample ball milled with different ball-to-powder ratio (a) 10:1, (b) 20:1, (c) 50:1 and (d) normalized XRD spectra of the initial hBN particles and the sheets ball milled with different ball-to-powder ratio without centrifugation.

Mentions: The milling effect of various ball-to-powder weight ratios were investigated using 1 mm steel balls for milling time of 10 h. Compared to the results from the ball-to-powder ratio of 10:1, a similar amount of BN nanosheets were produced when the ratio increased to 20:1 (Figure 2a). However, the 20:1 ratio produced more BN nanosheets less than 200 nm in diameter. When the 50:1 ratio was applied, many small particles instead of sheets were found. The formation of these particles are due to damage to the BN nanosheets20. This indicates that the increase of ball-to-powder ratio can result in higher yields of sheets, but at the cost of more structural damage owing to higher chance of ball-to-vial or ball-to-ball collision and also possibly stronger collision. The XRD patterns of samples milled with the different ball ratios are similar, and there is no noticeable broadening of the (002) and (004) peaks for all three samples (Figure 2c). Therefore, the ideal ball-to-powder ratio is 10:1.


High-Efficient Production of Boron Nitride Nanosheets via an Optimized Ball Milling Process for Lubrication in Oil
SEM images for sample ball milled with different ball-to-powder ratio (a) 10:1, (b) 20:1, (c) 50:1 and (d) normalized XRD spectra of the initial hBN particles and the sheets ball milled with different ball-to-powder ratio without centrifugation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: SEM images for sample ball milled with different ball-to-powder ratio (a) 10:1, (b) 20:1, (c) 50:1 and (d) normalized XRD spectra of the initial hBN particles and the sheets ball milled with different ball-to-powder ratio without centrifugation.
Mentions: The milling effect of various ball-to-powder weight ratios were investigated using 1 mm steel balls for milling time of 10 h. Compared to the results from the ball-to-powder ratio of 10:1, a similar amount of BN nanosheets were produced when the ratio increased to 20:1 (Figure 2a). However, the 20:1 ratio produced more BN nanosheets less than 200 nm in diameter. When the 50:1 ratio was applied, many small particles instead of sheets were found. The formation of these particles are due to damage to the BN nanosheets20. This indicates that the increase of ball-to-powder ratio can result in higher yields of sheets, but at the cost of more structural damage owing to higher chance of ball-to-vial or ball-to-ball collision and also possibly stronger collision. The XRD patterns of samples milled with the different ball ratios are similar, and there is no noticeable broadening of the (002) and (004) peaks for all three samples (Figure 2c). Therefore, the ideal ball-to-powder ratio is 10:1.

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.