Intrinsic and Defect-Related Elastic Moduli of Boron Nitride Nanotubes As Revealed by in Situ Transmission Electron Microscopy

On the Determination of Elastic Properties of Single-Walled Nitride Nanotubes Using Numerical Simulation

In recent years, tubular nanostructures have been related to immense advances in various fields of science and technology. Considerable research efforts have been centred on the theoretical prediction and manufacturing of non-carbon nanotubes (NTs), which meet modern requirements for the development of novel devices and systems. In this context, diatomic inorganic nanotubes formed by atoms of elements from the 13th group of the periodic table (B, Al, Ga, In, Tl) and nitrogen (N) have received much research attention. In this study, the elastic properties of single-walled boron nitride, aluminium nitride, gallium nitride, indium nitride, and thallium nitride nanotubes were assessed numerically using the nanoscale continuum modelling approach (also called molecular structural mechanics). The elastic properties (rigidities, surface Young's and shear moduli, and Poisson's ratio) of nitride nanotubes are discussed with respect to the bond length of the corresponding diatomic hexagonal lattice. The results obtained contribute to a better understanding of the mechanical response of nitride compound-based nanotubes, covering a broad range, from the well-studied boron nitride NTs to the hypothetical thallium nitride NTs.

A Simple Method for the Synthesis of a Coral-like Boron Nitride Micro-/Nanostructure Catalyzed by Fe

Catalyzed by Fe, novel a coral-like boron nitride (BN) micro-/nanostructure was synthesized from B₂O₃ by a ball milling and annealing process. Observations of the morphology of the product indicated that the coral-like BN micro-/nanostructure consists of a bamboo-shaped nanotube stem and dense h-BN nanoflakes growing outward on the surface of the nanotube. Experimental results showed that the morphology of the BN nanotube was greatly dependent on the anneal process parameters. With the annealing time increasing from 0.5 h to 4 h, the morphology developed from smooth BN nanotubes, with a diameter size of around 100 nm, to rough, coral-like boron nitride with a large diameter of 3.6 μm. The formation mechanism of this coral-like BN micro-/nanostructure is a two-stage growth process: bamboo-shaped BN nanotubes are first generated through a vapor-liquid-solid (VLS) mechanism and then nanoflakes grow surrounding the surface of the nanotube. Acid pickling and a hydrolysis process were carried out to remove Fe, iron nitrogen and unreacted B₂O₃ impurities.

Overview on the Evaluation of the Elastic Properties of Non-Carbon Nanotubes by Theoretical Approaches

Low-dimensional structures, such as nanotubes, have been the focus of research interest for approximately three decades due to their potential for use in numerous applications in engineering and technology. In addition to extensive investigation of carbon nanotubes, those composed of elements other than carbon, the so-called non-carbon nanotubes, have also begun to be studied, since they can be more suitable for electronic and optical nano-devices than their carbon counterparts. As in the case of carbon nanotubes, theoretical (numerical and analytical) approaches have been established predominantly to study non-carbon nanotubes. So far, most of work has dealt with the investigation of the structural and electrical properties of non-carbon nanotubes, paying less attention to the evaluation of their mechanical properties. As the understanding of the mechanical behaviour of the constituents is fundamental to ensure the effective performance of nanotube-based devices, this overview aims to analyse and systematize the literature results on the elastic properties of inorganic non-carbon nanotubes.