Improved anti-adhesive wear performance of rail/armature pair via interfacial energy modulation for electromagnetic launching applications

The prevention of adhesive wear between rail (made of high-strength Cu alloy) and armature (made of 7075 Al alloy) in the electromagnetic launching system is challenging due to the strong adhesion forces that arise from the interaction of asperities. Here, we propose a novel approach to enhance the anti-adhesive wear performance of rail through interfacial energy modulation between rail/armature pair for electromagnetic launching applications. Our findings indicate that the interfacial energy of the rail/armature pair can be significantly reduced by magnetron sputtering a W thin film onto the Al alloy surface. A lower coefficient of friction and a substantial alleviation in adhesion and mechanical damage of the Cu alloy are thus obtained. Molecular dynamics simulations reveal that the immiscibility and low interfacial energy of the Cu/W pair result in the formation of an amorphous interfacial layer during friction, facilitating countermotion at the contacting surfaces, thus in turn enables the low friction. The concept proposed in this work is further validated by real electromagnetic launching tests.