Unveiling ball size heterogeneity effect on microwave absorption properties of cobalt

Abstract

Recent advances in material science have led to impressive microwave absorbing materials, yet their practical applications are hindered by complex synthesis processes. This study explores a cost-effective alternative, emphasizing modifying material morphology using ball size heterogeneity. Unlike using same-sized balls, employing different-sized balls maximizes collision energy, yielding finer particles. In this study, the effect of ball size heterogeneity on microwave absorption performance has been investigated for the first time. An attempt has been made to explore how using ball size heterogeneity changes structural, magnetic, and dielectric properties of cobalt (Co) and how these modifications affect material's absorption properties. Results show that by using ball size heterogeneity, the particle size distribution in 0.1–1 μm range has been increased, yielding much finer particles. The relative permittivity value also increases due to changes in average particle size and surface area. Microwave absorption characteristics of Co milled with different-sized balls showed a significant change. A 15 h milled Co sample using different-sized balls achieved an effective bandwidth of 9.65 GHz (4.75–14.4), contrasting with no absorption bandwidth when using same-sized balls, with a 2 mm coating thickness. This work provides new insights into preparing materials for microwave absorption applications using ball milling method.