Direct nanomechanical measurements of boron nitride nanotube-ceramic interfaces

Thermal expansion of boron nitride nanotubes and additively manufactured ceramic nanocomposites

Controlling the thermal expansion of ceramic materials is important for many of their applications that involve high-temperature processing and/or working conditions. In this study, we investigate the thermal expansion properties of additively manufactured alumina that is reinforced with boron nitride nanotubes (BNNTs) over a broad temperature range, from room temperature to 900 °C. The coefficient of thermal expansion (CTE) of the BNNT-alumina nanocomposite increases with temperature but decreases with an increase in BNNT loading. The introduction of 0.6% BNNTs results in an approximate 16% reduction in the CTE of alumina. The observed significant CTE reduction of ceramics is attributed to the BNNT's low CTE and ultrahigh Young's modulus, and effective interfacial load transfer at the BNNT-ceramic interface. Micromechanical analysis, based onin situRaman measurements, reveals the transition of thermal-expansion-induced interface straining of nanotubes, which shifts from compression to tension inside the ceramic matrix under thermal loadings. This study provides valuable insights into the thermomechanical behavior of BNNT-reinforced ceramic nanocomposites and contributes to the optimal design of ceramic materials with tunable and zero CTE.

BNNT vs. CNT: influence of structural defects on damping characteristics of nanocomposites

The viscoelastic damping of nanocomposites reinforced with BNNTs and CNTs was compared. MD simulations revealed that the interfacial damping of pristine-CNT was superior to that of pristine-BNNT. The contrasting effects of structural defects were elucidated using interfacial adhesion, interphase, and overlapping phonon density of states in the nanotubes and polymers.

An overview of the recent advances in inorganic nanotubes

Advanced nanomaterials play a prominent role in nanoscience and nanotechnology developments, opening new frontiers in these areas. Among these nanomaterials, due to their unique characteristics and enhanced chemical and physical properties, inorganic nanotubes have been considered one of the most interesting nanostructures. In recent years, important progress has been achieved in the production and study of these nanomaterials, including boron nitride, transition metal dichalcogenide nanotubular structures, misfit-based nanotubes and other hybrid/doped nanotubular objects. This review is devoted to the in-depth analysis of recent studies on the synthesis, atomic structures, properties and applications of inorganic nanotubes and related nanostructures. Particular attention is paid to the growth mechanism of these nanomaterials. This is a crucial point for the challenges ahead related to the mass production of high-quality defect-free nanotubes for a variety of applications.