Investigation of the Cubic Boron Nitride Nucleation under the High Pressure and the High Temperature

TL;DR

This paper presents a theoretical analysis of the nucleation process of cubic boron nitride (cBN) under high pressure and temperature, including activation energy calculation, phase boundary determination, and formation time estimation.

Contribution

It introduces an analytical formula linking nucleus formation time with activation energy, pressure, and temperature, and determines the cBN nucleation boundary in the phase diagram.

Findings

Activation energy for hBN to cBN transformation is 420.38 kJ/mol.

cBN nucleus formation time is less than 300 ms.

Theoretical predictions align with experimental data.

Abstract

In this paper we have theoretically found the activation energy ($420.38kJ/mol$) for the transformation from hBN to cBN in the microscopic viewpoint. We have introduced an analytical formula representing the dependence of nucleus formation time on the activation energy, synthesis pressure and temperature. We have theoretically determined the boundary line of cBN nucleus formation region in the $P-T$ phase diagram on the basis of the diffusion mechanism of cBN nucleus formation. We have found that the cBN crystal nucleus formation time is less than $300ms$ by comparing of the theory and experiment.