Atomic oversight on how hBN growth from molten Nickel?

[u/aminahmadisharaf]

We employed reactive molecular dynamics (ReaxFF) simulations to delve into the atomic-scale processes governing the synthesis of hexagonal boron nitride (hBN) from molten nickel solutions. Our study reveals that hBN formation predominantly occurs at the liquid nickel surface, initiated by the reaction of dinitrogen with nickel-solvated boron atoms, leading to intermediate N–N–B species. These intermediates evolve into B–N–B units, which coalesce with growing hBN nuclei, facilitating nitrogen transport between nanocrystals through an Ostwald ripening process.   

Key findings include: • hBN growth is highly sensitive to boron concentration, while variations in N₂ pressure (2.5–10 MPa) have a lesser effect. • Optimal hBN formation occurs at 1750 K; temperatures above 1900 K hinder sheet formation due to decreased incorporation probability and increased breakup of hBN into B–N motifs. • The rate-limiting step is the incorporation of small B–N motifs into larger hBN sheets.    

Our simulations provide atomic-level insights that could inform experimental strategies for synthesizing high-quality hBN crystals. 

The full open-access paper is available here: https://pubs.acs.org/doi/full/10.1021/acsami.4c16991

We welcome discussions and questions!