Air-plasma sprayed Al-B₄C composite coating for advanced radiation shielding

Radiation shielding is essential to protect people, equipment, and the environment from the harmful effects of ionizing radiation. Al-B₄C composite is a strong candidate in this field. Developing the composite with high reinforcement content without segregation has been a problem in conventional manufacturing methods. In this work, a novel homogeneously reinforced feedstock powder, manufactured by mechanical alloying, is air plasma sprayed to produce a highly reinforced, homogeneously distributed Al-40vol%B₄C composite coating. The microstructure and composition of the coating are analyzed by SEM and XRD. The coating presented a dense microstructure and a similar composition to that of the powder, suggesting no degradation of boron carbide during plasma spraying. Image analysis revealed a low porosity of around 0.2 % in the coating. Tensile test performed on the coating revealed that it had a cohesive strength exceeding 60 MPa, primarily due to improved inter-lamellar bonding and stronger matrix-reinforcement interfacial contact. Low porosity and improved inter-lamellar bonding in the coating enhance radiation shielding ability by reducing radiation leakage paths, thereby ensuring continuous shielding through increased material-radiation contact.