2D Nanomaterial-Reinforced Copper Matrix Composites for Tribological Applications

Abstract

Copper is widely used in electrical components, including switching devices, due to its excellent electrical conductivity. However, copper-based switching components are susceptible to friction and wear during repeated sliding contact. While oil- and grease-based lubricants can reduce friction and wear, they require maintenance, and their performance depends on operating conditions. This creates a need for lowfriction, wear-resistant materials to enable efficient, reliable switching performance. This thesis investigates whether MXene reinforcement can improve the tribological performance of copper matrix composites for electrical switching applications. MXene-Cu composites with MXene loadings ranging from 0.5 wt.% to 2.5 wt.% were fabricated and evaluated using linear reciprocating ball-on-flat measurements. The composites were characterized before and after sintering, and after tribological testing, using optical microscopy, SEM, and EDS. The MXene-Cu composites were also compared with additional material systems, namely Graphene-Cu and MXene- Graphene-Cu hybrid composites. During the tribomechanical evaluation, the pure Cu reference was prematurely interrupted due to excessive friction. Although the measurement of one MXene-Cu composite was interrupted due to excessive friction, all other MXene-Cu composites finished the measurement. This indicates that MXene reinforcement improved sliding durability compared with pure Cu. However, the sintered MXene-Cu composites still exhibited relatively high coefficients of friction, ranging from 0.62 to 0.949, and no sustained low-friction behavior comparable to the greased reference was achieved. The 2 wt.% MXene-Cu composite showed the lowest mean coefficient of friction (CoF) among the sintered MXene-Cu samples, but the initial friction reduction was not sustained for the entire measurement. SEM and EDS analysis suggested surface smearing and compacted wear layers, but did not confirm the formation of a continuous MXene-derived lubricating tribofilm. Overall, MXene reinforcement showed potential for improving sliding durability, but further optimization of composition, processing, and surface condition is required before practical application in electrical switching devices can be considered.