Modification Technology of 3D-Printed Silicon Carbide Space Mirrors

Abstract

To address the key challenges of 3D-printed silicon carbide (SiC) mirrors—namely, high porosity and numerous interlayer defects arising from the layer-by-layer stacking process, resulting in a surface roughness of approximately 40 nm RMS after direct polishing that fails to meet optical requirements—this study employs ion-beam-assisted deposition (IBAD) technology. The aim is to develop a surface modification method that balances thick-film coverage capability with reduced thermal residual stress, providing a flexible and efficient engineering solution for 3D-printed SiC mirrors. By adjusting ion source parameters, deposition rate, and substrate temperature, two silicon modification processes—cold deposition (25 °C) and hot deposition (150 °C)—were developed on the same equipment. The results show that the modified layers prepared by both processes are dense and uniform, effectively covering the micropores and residual carbon defects inherent in 3D-printed SiC, and both exhibit excellent adhesion performance. After polishing, the surface roughness of the modified layer using the cold-deposition process is <1 nm RMS, while that using the hot deposition temperature process is <2 nm RMS, satisfying the requirements for optical mirror applications. The cold-deposition process is suitable for thin-walled complex structured mirrors, whereas the hot-deposition process is suitable for high-stiffness mirrors with simple geometries. By flexibly tuning process parameters on a single platform, IBAD enables high-quality modification of 3D-printed SiC mirrors, providing technical support for their application in low-cost space optical systems.