Structural, Mechanical, and Electrochemical Characterization of NiCrCu Matrix Composites Reinforced with Co and Mo Additions
摘要
This work investigates the effects of Co and Mo additions on the mechanical, electrochemical, tribological, and microstructural characteristics of NiCrCu matrix composites, which may be used in demanding environments for high-performance applications. The composites are made using the powder metallurgy technique. XRD and SEM-EDX revealed multiphase structures, including intermetallic phases. Ni30Cr10Cu has the highest hardness at 114.2 ± 6 HV, followed by Ni30Cr10Cu6Mo at 113.7 ± 6 HV, and the lowest hardness is for the Ni30Cr10Cu6Co alloy (110.6 ± 14 HV). The Ni30Cr10Cu6Mo composite demonstrated the highest tribological performance at 15 N with the lowest wear rate of 0.113 × 10−5 g/m. Potentiodynamic polarization revealed that Ni30Cr10Cu6Mo had the lowest corrosion rate (0.463 mm/y) and maximum corrosion potential (−0.176 V) in 3.5% NaCl, while Young’s modulus increased from 173.8 GPa in Ni30Cr10Cu to 243.3 GPa in Ni30Cr10Cu6Co and 242.7 GPa in Ni30Cr10Cu6Mo. The maximum polarization resistance, as determined by electrochemical impedance spectroscopy (EIS), is 8.16 kΩ cm2 for Ni30Cr10Cu6Mo. Mo forms a protective surface layer, as indicated by EDX analysis of corroded surfaces. These findings demonstrate that molybdenum enhances the composite’s wear and corrosion resistance, making Ni30Cr10Cu6Mo a suitable option for harsh-service applications.