The growing demand for sustainable construction materials has sparked interest in innovative cementitious components that improve performance while mitigating environmental impact. This study explores the influence of red phosphorus (P) on the crystallization dynamics and electrochemical stability of Portland cement. Specifically, we investigate how varying phosphorus concentrations (0–10%) affect phase evolution and structural integrity. A comprehensive suite of analytical techniques, including field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), electron probe microanalysis (EPMA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), was employed to characterize crystallization behavior. Additionally, open circuit potential (OCP), potentiodynamic polarization tests, and electrochemical impedance spectroscopy (EIS) were utilized to evaluate electrochemical properties. Quantitative defect analysis showed that the number of pores increased from 150 ± 22 to 420 ± 22 ea/mm², the crack width increased from 0.10 ± 0.01 to 1.40 ± 0.60 μm, and the crack length increased from 1.20 ± 0.20 to 4.20 ± 1.21 μm. In addition, OCP shifted from −0.16 ± 0.01 to −0.27 ± 0.03 V, I_corr increased from 2 × 10⁻⁷ ± 1 × 10⁻⁸ to 8 × 10⁻⁷ ± 3 × 10⁻⁸ A/cm², and R_p decreased from 10.5 ± 0.4 to 6.0 ± 0.2 kΩ with increasing P composition, indicating deterioration of the microstructural and electrochemical stability of the cement matrix. These findings provide quantitative guidance for controlling phosphorus utilization in cement formulations.

Al-based composites have attracted significant attention in the aerospace, automotive, and electronic industries due to their lightweight characteristics, high specific strength, and superior thermal conductivity. Although Al–cBN composites exhibit enhanced mechanical and wear properties, galvanic interactions between the Al matrix and carbon-based reinforcements can accelerate localized corrosion and reduce electrochemical stability in chloride-containing environments. To improve these limitations, Ni coating has been considered an effective surface modification method because of its high corrosion resistance and electrochemical stability. However, investigations on the surface and electrochemical behavior of Ni-coated Al–cBN composites remain limited. In this study, the surface characteristics and electrochemical behavior of Ni-plated Al–cBN composites were systematically investigated. Surface morphology and microstructural evolution were analyzed using FE-SEM, while crystallographic characteristics and phase evolution were examined through XRD analysis. In addition, electrochemical properties were evaluated using OCP and potentiodynamic polarization measurements. The results revealed that the specimen plated for 600 s exhibited a corrosion potential shift from −0.92 V to −0.38 V, together with a significant reduction in corrosion current density, indicating improved electrochemical stability and corrosion resistance due to the formation of a dense Ni coating layer. These results demonstrate that electroless Ni plating is an effective surface modification technique for enhancing the corrosion resistance and electrochemical stability of Al–cBN composites.