Improvement of interfacial bonding in carbon nanotube reinforced Fe–50Co composites by Ni–P coating: Effect on magnetic and mechanical properties

Graphical abstract: - Highlights: • Drying of Ni–P coated CNTs in ethanol under atm. conditions promotes GO formation. • Ball milling helps to disperse CNTs uniformly in matrix than ultrasonication. • Increase in vol% of coated CNTs higher than 1.5% reduces mechanical properties. • Addition of coated CNTs improves both ductility and strength unlike bare CNTs. • Spark plasma sintering helped to preserve the structural quality of CNTs. - Abstract: Fe–50Co matrix composites containing 1.5 and 3 vol% of electroless Ni–P plated carbon nanotubes (CNTs) were densified using spark plasma sintering. The powder mixtures for the composites were prepared by two different routes: (a) ultrasonication only; and (b) ultrasonication followed by dry ball milling. Drying of the Ni–P plated CNTs under atmospheric conditions in the presence of ethanol promoted the nucleation and growth of graphene oxide on the coating. The ball milling route was found to be the most efficient method to disperse the coated nanotubes uniformly in the matrix. The addition of coated CNTs, which formed Taenite phase with the matrix alloy, made the composites to exhibit: (a) higher ductility, higher flexural strength, lower coercivity (H_c) and lower saturation induction (B_sat) compared to the monolithic material; and (b) higher ductility, higher flexural strength, higher H_c and lower B_sat in relation to the material with similar amount of bare CNTs