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

## TL;DR

This paper presents a scalable, solvent-free method to exfoliate 2D materials and coat metal powders, creating composites with high thermal conductivity suitable for advanced manufacturing.

## Contribution

A novel solvent-free ball milling method for exfoliating 2D materials and coating metal powders, supported by DFT and DEM simulations.

## Key findings

- Graphene and hBN were successfully exfoliated and coated onto various metal powders using solvent-free ball milling.
- Titanium alloy/graphene composites achieved thermal conductivity up to 17 W·m⁻¹·K⁻¹ after consolidation.
- The method is scalable and compatible with large-scale manufacturing techniques.

## 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.