Research and applications of additive manufacturing technology of SiC ceramics

Silicon carbide (SiC) ceramic material shows significant application prospects in engineering and technical fields, such as aerospace, nuclear energy, and automobile industry engineering, due to its excellent mechanical, thermal, and optical properties. It is also key to the breakthrough of national scientific research and important strategic equipment. In recent years, the requirement of high-performance SiC ceramic components with complicated shapes, such as lightweight space optical mirrors, is becoming increasingly stringent, pushing the need for ceramic processing techniques. Traditional manufacturing techniques for SiC ceramic components include slip casting, isostatic pressing, and injection molding, etc. However, these processing methods have certain restrictions, including the requirement of molds and tools, time-consuming steps, high cost, and incapability to prepare SiC ceramic parts with complex shapes and arbitrary geometries. Additive manufacturing (AM) technology has provided a new development direction for the preparation of SiC ceramic. Different from the conventional processing methods, AM is performed in a layer-by-layer fashion to fabricate the components from a computer-aided design model. It theoretically allows the production of complex-shaped SiC ceramic parts without the requirement of molds, thus overcoming the shortcomings of the conventional methods in fabricating complicated ceramic components. The AM technique has become an effective way to achieve lightweight SiC ceramic formation and integration of complex SiC ceramic components. Currently, the AM of SiC ceramics has become a research hotspot in this field. In this review, the recent advances in the research and applications of SiC ceramics prepared by AM are systematically summarized and discussed, including the material design and fabrication methods, processes and equipment, post-processing technology, finite element simulation, performance evaluation, and desired applications. After briefly introducing the general research ideas and expected results of SiC ceramics via additive manufacturing, the design and preparation methods of AM-based SiC materials, including SiC powder, slurry/paste, filament, and laminate, are described in detail. Subsequently, the common AM process of SiC ceramics is introduced, including selective laser sintering, three-dimensional printing, stereolithography, direct ink writing, fused deposition modeling, and laminated object manufacturing. Further, post-treatment processes of the green body for AM-based SiC ceramics are presented, including carbonization, liquid/gas silicon infiltration, chemical vapor infiltration, and precursor impregnation and pyrolysis. In addition, this paper summarizes the finite element simulation of AM and post-treatment process for SiC ceramics and illustrates the performance evaluation methods of SiC ceramic components, including their mechanical, thermal, and optical performances. Typical applications of AM-based SiC ceramic components are elaborated as well. Finally, the outstanding challenges, future directions, and potential perspectives related to AM-prepared SiC ceramics are proposed. In the future, the AM-prepared SiC components will develop toward the advanced directions, such as the SiC ceramics with micro- or macroscale structures, lightweight SiC ceramics, the application of SiC composite material, and the material-structure-function combination for SiC ceramics. The purpose of this paper is to provide a significant reference for the research of complex SiC ceramic components fabricated via AM.