Phase Stability of Hexagonal/Cubic Boron Nitride Nanocomposites

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Boron nitride (BN) exists in various polymorphs, with 2D hexagonal BN (h-BN) and 3D cubic BN (c-BN) being the most prevalent.
• The phase stability and transformation mechanisms of BN polymorphs are not fully understood, presenting challenges for material design.

Purpose of the Study:

• To investigate the phase stability of 2D/3D h-BN/c-BN nanocomposites.
• To explore the relationship between phase coexistence and material properties.
• To understand the phase transformation kinetics during sintering.

Main Methods:

• Synthesis and characterization of 2D/3D h-BN/c-BN nanocomposites.
• Analysis of nonlinear optical properties and thermal conductivity at room temperature.
• Spark-plasma sintering (SPS) to induce phase transformations.

Main Results:

• The coexistence of h-BN and c-BN phases in nanocomposites leads to strong nonlinear optical properties and low thermal conductivity.
• Spark-plasma sintering resulted in a complete phase transformation to 2D h-BN with enhanced crystalline quality.
• Evidence suggests that 3D c-BN plays a role in the nucleation and growth kinetics during phase transformation.

Conclusions:

• Phase engineering of BN nanocomposites can yield materials with tunable optoelectronic and thermal management properties.
• The study provides insights into controlling BN phase transformations for advanced material applications.
• The findings are relevant for developing next-generation materials for optoelectronics and thermal management.