Hybrid Bond Layers for Cold Spray Metallization of CFRP Surfaces

초록

To metallize non-metallic surfaces by cold spray, bond layers (BLs) are often used to achieve a degree of compatibility between the substrate and the deposit and generally to mitigate the disparate properties of substrate and deposit. The objective of the present work is to design hybrid (Al-epoxy) BLs for metallization of epoxy-based carbon fiber-reinforced polymers (CFRPs) and to determine parametric effects on adhesion and deposition yield. The few studies that have focused on metal deposition onto thermoset composites have highlighted risks of erosion of the thermoset matrix and of fiber fracture. To address these problems, a BL is introduced to reduce erosion of CFRP and to provide surfaces for impinging powder to cold-weld onto and interlock. Effort is devoted to engineer a BL compatible with cold spray and to develop understanding of the quantitative effects of BL microstructure on adhesion. The BL microstructure strongly affected the adhesion of the deposit, which relied on BL-CFRP, powder-BL, and powder-powder bonding. Analysis of initial stages of deposition revealed matrix erosion and subsequent compaction, both contributing to mechanical interlocking. The findings indicate a pathway for CS deposition onto CFRP through judicious design of BLs.

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