Electrochemical additive manufacturing of ultra-low friction multilayered Ni nanocomposite coatings reinforced by heterostructured 2D materials

Achieving low-friction, high-durability mold surfaces remains a significant challenge in polymer micro/nano replication, as conventional Ni molds often suffer from severe interfacial adhesion and wear. To address this, this work develops an innovative heterostructured 2D materials (WS2, MoS2, and BN) reinforced multilayered Ni nanocomposite self-lubricating coating fabricated through electrochemical additive manufacturing approach. This method enables precise layer-by-layer control and selective integration of 2D materials, forming dense, grain-refined microstructures with tailored surface textures. Remarkably, the optimized triple-layer Ni-(WS2-MoS2-BN) coating achieves a hardness of 252 HV and an ultra-low coefficient of friction of 0.04, outperforming single- and double-layer coatings. This performance is attributed to enhanced equiaxed grain formation, interlayer shearing, and self-lubricating tribofilm development under load. Extended sliding tests further reveal long-term wear resistance and surface integrity. Mechanistically, synergistic interactions among 2D material phases govern crystal orientation, dislocation behavior, and tribofilm evolution. These findings reveal the role of multilayered architectures in simultaneously tuning mechanical strength and frictional behavior of the coatings. This work not only advances the design of self-lubricating coatings but also provides a scalable solution for producing high-performance mold tools, enabling defect-free, high-fidelity replication in next-generation micro/nano manufacturing.