Sustainable, solvent-free exfoliation of 2D materials for thermally conductive metal powder coatings

Abstract

2D nanomaterials offer unique functional properties when combined with metal powder feedstock, enabling advanced composites for engineering and energy applications1. Scalable fabrication of nanosheet-reinforced metal matrix composites (2DMMCs) remains challenging. In this study, we first exfoliate 2D materials using a solvent-free ball milling approach, using graphene and hexagonal boron nitride (hBN) as demonstrators, and then attach the resulting 2D nanoplatelets onto a wide range of metal powders, including copper (Cu), titanium (Ti-6Al-4V), aluminum (AlSi10Mg), and stainless steel (SS316L). To provide a mechanistic understanding of exfoliation, we use density functional theory (DFT) and discrete element method (DEM) simulations, offering new insights into the forces that drive nanosheet exfoliation. The resulting 2DMMC powders combine excellent scalability and effectiveness. After consolidation, titanium alloy/graphene systems reaching thermal conductivity values of 17 W·m⁻¹·K⁻¹, comparable or superior to previous reports. Finally, we showcase their printability, confirming compatibility with large-scale manufacturing techniques and highlighting their potential for next-generation thermal applications.