Comparative investigation of the microstructure, mechanical, corrosion, and wear properties of AISI 1040 steel borided with different activators

Despite its widespread use, AISI 1040 steel suffers from limited hardness and poor wear and corrosion resistance. Boronizing enhances these properties through boron diffusion at elevated temperatures. In this study, AISI 1040 steel specimens were pack-boronized using two boronizing agents containing single and dual activators at 950°C for 2, 4, and 6 h. The microstructural, mechanical, and corrosion properties of the borided layers were evaluated using standard characterisation and testing methods. The results revealed that the dual-activator boronizing agent significantly promoted Fe₂B phase formation and provided the highest wear resistance. The resulting boride layers exhibited a maximum hardness of 2095 ± 65 HV₀.₃ and a maximum thickness of 314.16 ± 10 μm. Accordingly, the wear resistance of the dual-activator boronized specimens was 6.5 times higher than that of the untreated samples and 2.1 times higher than that of the single-activator boronized samples. In addition, corrosion resistance increased by up to 40.54 times and hardness increased approximately tenfold compared with the untreated steel. Dual-activator boronizing effectively improved the surface performance of medium-carbon steels.