Hot Centrifugal Coating: A Novel Method for Enhancing Diffusion Bonding Integrity at Steel-Brass Interfaces

Steel cylinders are widely used in industry, but their service life is often limited by corrosion and wear. Conventional coating methods generally produce only mechanical bonds and can lead to delamination and interfacial failure. Therefore, this study proposes a Hot Centrifugal Coating (HCC) method that combines centrifugal casting with substrate heating to the austenitization temperature during processing. Diffusion bonding is achieved through a hybrid kinetic–thermal process. The Taguchi L9 design was used to evaluate the effects of temperature, rotational speed, and flux treatment. Diffusion bonding was confirmed through FESEM–EDX analysis, microhardness profiling, and pull-off adhesion testing. The experimental results show that substrate austenitization is a key factor in the formation of a graded diffusion zone (30–40 μm). At the interface, the hardness increases to 161–283 HV, exceeding that of both the substrate and the coating. Fracture analysis shows a predominantly cohesive failure mode with a bond strength of 110–148 MPa. These results demonstrate that the HCC method effectively produces high-integrity brass–steel coatings and shows strong potential for scalable applications in corrosion- and wear-resistant cylindrical components.