Influence of Ti3SiC2 Max Phase Addition on the Tribological Performance of Ni-Cr Coatings

Abstract Spacecraft components are subjected to extreme thermal fluctuations during transitions between the bright and dark sides of the Moon, which accelerates wear and diminishes the frictional performance of metallic materials. Applying multifunctional coatings is a promising approach to promoting the durability of the metallic components of spacecrafts. Ni-Cr coatings, known for their mechanical strength, temperature resilience, and radiation resistance, are often used in high-temperature environments. However, these coatings suffer from brittleness, poor adhesion, suboptimal wear, and frictional properties. This study explores the enhancement of Ni-Cr coatings by incorporating the layered ternary carbide MAX phase (Ti3SiC2) as dopants, which exhibit enhanced thermal shock resistance and lubrication properties. In this study, Ni-Cr-Ti3SiC2 coatings were fabricated using selective laser sintering with 0%, 5%, and 10% MAX phase compositions. The coatings were characterized using Scanning Electron Microscopy (SEM) for topological analysis and Energy Dispersive Spectroscopy (EDS) for chemical composition. Through the characterization, the effect of multiple laser sintering cycles on the dispersion of the Ni-Cr coating was analyzed. It was observed that higher sintering cycles improved the dispersion of the Ni-Cr coating. Subsequently, the addition of Ti3SiC2 further contributed to the enhanced dispersion of the coating. Tribological performance, including coefficient of friction, wear resistance, and durability, was assessed using a standard ball-on-disc tribometer. The coefficient of friction (CoF) results showed that Ni-Cr coating with three laser cycles maintained a stable CoF around 0.45 up to 3,500 cycles, where two laser and one laser cycle samples exhibited CoF of around 0.50 and 0.55, respectively, up to 1250 and 350 cycles. Moreover, Ni-Cr coatings containing MAX phase exhibited 25 times greater durability than the samples without MAX phase and lasted up to 70,000 cycles with a maximum CoF value of 0.55. Wear track analysis indicated that the MAX phase promoted the formation of transfer films, reducing abrasive wear and stabilizing the Ni-Cr matrix by minimizing chromium oxidation.