Boron Nitride Nanotubes: Characteristics, Manufacture, and Applications

Description

Boron Nitride Nanotubes are nanometre‐scale cylindrical structures composed of boron and nitrogen atoms arranged in a hexagonal lattice. They possess a tube geometry that differs from Carbon Nanotubes in electrical function and thermal behaviour. Their properties, including thermal stability at temperatures exceeding 900 °C, chemical inertness and measurable mechanical strength, support their utilisation in specialised industrial applications.

Production of Boron Nitride Nanotubes

Several methods exist for the synthesis of Boron Nitride Nanotubes in laboratory and industrial settings. One common approach is chemical vapour deposition. In this method, high‐temperature reactors operating at temperatures above 900 °C are used; gases containing boron and nitrogen are introduced under controlled temperature, pressure and gas flow rates. Another procedure uses a ball milling technique, whereby boron and nitrogen sources are ground together at high energy levels to promote nanotube formation. A laser ablation method has also been demonstrated; here, a laser beam vapourises a target that is rich in boron and nitrogen in a carefully controlled environment.

Every process requires precise regulation of temperature, pressure and gas flow. Catalysts may be applied in some methods to guide tube formation, whereas other methods proceed without catalysts. Each step is monitored to ensure that the resulting nanotubes meet the required dimensions and purity. Consequently, improvements in production techniques have reduced costs and increased yield over time.

Boron Nitride Nanotubes Characteristics

Boron Nitride Nanotubes can withstand temperatures above 900 °C; in some tests, they have been operated at temperatures up to 1 000 °C. They possess a low density and a confirmed mechanical strength that enables their use in load‐bearing applications. Their chemical inertness means they exhibit limited reactivity with aggressive chemicals. In contrast to Carbon Nanotubes, Boron Nitride Nanotubes act as electrical insulators. Studies indicate that their electrical resistivity exceeds that of carbon‐based materials. They also demonstrate high thermal conductivity, thereby facilitating heat transfer in electronic systems.

Further reading: Boron Nitride Guide: Properties, Structure & Applications

Boron Nitride Nanotubes Applications

Boron Nitride Nanotubes are applied across various sectors. In aerospace and defence, they are incorporated into composite materials to improve thermal performance and mechanical integrity with a reduction in overall weight. They may be added to composite coatings to enhance heat resistance and structural stability. In electronic devices, their insulating characteristics are used to prevent electrical leakage. In certain composite formulations, they are included as a reinforcement phase. Given that their thermal stability supports performance in environments subject to high thermal loads, they have been employed in nuclear reactor applications.

Medical research laboratories have investigated the incorporation of Boron Nitride Nanotubes in drug delivery systems and imaging techniques. In these studies, the nanotubes have been integrated into controlled‐release carriers on account of their chemical inertness and low toxicity. Some investigations have evaluated their performance within biological environments.

Comparison of Boron Nitride Nanotubes and Carbon Nanotubes

Carbon Nanotubes enable electrical conduction. In contrast, Boron Nitride Nanotubes function as electrical insulators. They are capable of operating at higher temperatures, given that Carbon Nanotubes may oxidise or combust under similar conditions. Both nanotube types have been shown to improve the mechanical performance of composite materials.

Conclusion

Boron Nitride Nanotubes exhibit potential for a range of applications. Their operational stability at temperatures exceeding 900 °C and resistance to chemically reactive environments supports their utilisation in electronic insulation and composite reinforcement. They serve as an alternative to Carbon Nanotubes in scenarios that demand sustained thermal performance and chemical inertness.

Frequently Asked Questions

F: What are Boron Nitride Nanotubes made of?
Q: They consist of boron and nitrogen arranged in a hexagonal lattice.

F: Do Boron Nitride Nanotubes conduct electricity?
Q: No, they act as electrical insulators under standard conditions.

F: How are Boron Nitride Nanotubes used in composites?
Q: They are incorporated to improve strength and heat resistance.

Reference:

1.        Bansal, N. P., Hurst, J. B., & Choi, S. R. (2006). Boron nitride nanotubes‐reinforced glass composites. 30th International Conference and Exposition on Advanced Ceramics and Composites, 22/01/2006, Cocoa Beach, Florida.

2.        Lahiri, D., Singh, V., Li, L. H., Xing, T., Seal, S., Chen, Y., & Agarwal, A. (2012). Insight into reactions and interface between boron nitride nanotube and aluminium. Journal of Materials Research, 27(21), 2 760–2 770. https://doi.org/10.1557/jmr.2012.294

3.        Thibeault, S. A., Fay, C. C., Earle, K. D., Lowther, S. E., Sauti, G., Kang, J. H., Park, C., & McMullen, A. M. (2014). Radiation shielding materials containing hydrogen, boron, and nitrogen. NASA Technical Memorandum, 31/01/2014.