Additive manufacturing of Polymer-Derived Ceramics (PDCs) is regarded as a disruptive fabrication process that includes several technologies such as light curing and ink writing. However, 3D printing based on material extrusion is still not fully explored. Here, an indirect 3D printing approach combining Fused Deposition Modeling (FDM) and replica process is demonstrated as a simple and low-cost approach to deliver complex near-net-shaped cellular Si-based non-oxide ceramic architectures while preserving the structure. 3D-Printed honeycomb polylactic acid (PLA) lattices were dip-coated with two preceramic polymers (polyvinylsilazane and allylhydridopolycarbosilane) and then converted by pyrolysis respectively into SiCN and SiC ceramics. All the steps of the process (printing resolution and surface finishing, cross-linking, dip-coating, drying and pyrolysis) were optimized and controlled. Despite some internal and surface defects observed by topography, 3D-printed materials exhibited a retention of the highly porous honeycomb shape after pyrolysis. Weight loss, volume shrinkage, roughness and microstructural evolution with high annealing temperatures are discussed. Our results show that the sacrificial mold-assisted 3D printing is a suitable rapid approach for producing customizable lightweight highly stable Si-based 3D non-oxide ceramics.

Nickel(II) hydroxycarbonate colloids were synthesized in water by the reaction of nickel(II) with carbonate in the presence of hexadecyltrimethylammonium bromide. Then, they were dispersed onto SBA-15 affording, after calcination and reduction, a supported 3 wt.% nickel(0) catalyst for the dry reforming of methane (DRM). This material, compared to reference ones obtained by impregnation, either by organic Ni(0) colloids or by aqueous nickel(II), was characterized by small nickel nanoparticles leading to improved activity and stability. Such use of aqueous nickel(II) hydroxycarbonate colloids instead of organic Ni(0) ones synthesized with harmful reagents is a new and a more efficient and environment-friendly approach.