Bionic Multilevel Composite Structures Design in Ag-CuO Contacts for Synergistically Enhancing Erosion and Impact Resistance.

The synergistic enhancement effect among multilevel composite structures is essential for improving the overall performance of contacts. Notably, natural bamboo demonstrates exceptional mechanical properties through the coupling effect of its structure. By reforming the microstructure of bamboo, an Ag-CuO contact, consisting of the Ag-rich regions, the CuO chain-like skeleton regions, and the CuO barrier layers, was inversely designed and controllably fabricated. Through experiments coupled with Computational Fluid Dynamics (CFD) and Finite Element Method (FEM) simulations, the synergistic effects of these structures units in improving arc erosion and impact resistance were explored. Results show that interactions among multilevel structures markedly refine the erosion morphology on the contact surface. Specifically, the Ag-rich regions ensure stable conductive and thermal pathways within the molten pool while serving as a dependable Ag source supplement for erosion layer, showing excellent self-compensation and repair ability. Additionally, the dynamic evolution of this multilevel structures suppresses the formation of the CuO segregation layers. The restructured ″chain-like″ and ″scatter-island″ CuO skeletons are evenly distributed within the Ag matrix, forming a three-dimensional interpenetrating network structure. This structure disintegrates the molten bridge and increases the tortuosity of flow paths, thus enhancing erosion resistance. Benefiting from this biomimetic design strategy, CuO chain-like skeleton regions reduces the local stress and deformation concentration, while the Ag-rich regions and the CuO barrier layers improving energy absorption and impact resistance of the contacts, effectively inhibiting the interface debonding. Therefore, this reformative structure inspired by bamboo provides a compelling route for the research of advanced Ag-based contacts.