3D-printed SiZrOC/hBN Moiré pattern structures with macroscopic ultralow friction and wear

Ceramics demonstrate irreplaceable advantages for lubrication under extreme environments. However, developing advanced ceramic-based lubricating materials with macroscopic ultralow friction and wear remains challenging. Herein, by synergistically combining Zr-doped SiOC molecular modification and 3D printing technique, SiZrOC Moiré pattern structures featuring different rotation angles were developed. Specially, SiZrOC Moiré pattern structure with a rotation angle of 13.2° achieved outstanding tribological properties, maintaining a stable average coefficient of friction (COF) value of ∼ 0.2, as well as a low wear rate of 1.01 × 10⁻⁶ mm³ꞏN⁻¹ꞏm⁻¹, even under a normal load of 10 N. To realize macroscopic ultralow friction and wear, hBN lubricating coating was further applied to the optimal SiZrOC Moiré pattern structure, constructing SiZrOC/hBN Moiré structures. As expected, SiZrOC/hBN Moiré structures showed significant friction reduction, with an average COF value of 0.095. The exceptional lubrication performance could be ascribed to the combined effects of good flatness, small contact area and unique debris/lubricant storage capacity of Moiré pattern structures with fractal design, excellent wear-resistance ability of SiZrOC hard ceramic substrate, and superior easy-to-shear character of hBN soft lubricating layer. This study provides a promising avenue for accelerating the application of advanced ceramic-based lubricating materials in both industrial production and daily life.