In Situ Fabrication of Gradient Porous Layers on Sintered Metallic Substrates via Surface Friction Treatment

This work pioneers the novel application of surface friction treatment (SFT) to sintered porous metals to fabricate gradient-structured functional surfaces. The results demonstrate that SFT significantly modifies surface pore architecture, with scanning velocity and normal load critically controlling gradient layer formation. Excessive parameters induce periodic surface cracking due to mechanical overloading. Post-treatment, the porous metal exhibits a 37.5% reduction in maximum pore size (24 μm to 15 μm) and substantially improved surface finish, with arithmetic mean roughness (Ra) decreasing from 23.8 μm to 4.3 μm (82% reduction). These surface enhancements significantly improve filtration functionality while providing a cost-effective alternative to conventional gradient layer fabrication methods.