The Study Of Light-Weight And High-Strength Polymer-Derived Ceramics By Photocuring 3D Printing

As specialty ceramics play an increasingly important role in a variety of high-end fields,the demand for high-performance micro-nano ceramics is growing.The functionalization of ceramic devices depends on micro-macroscopic multi-level order regulation of physical structure and multi-component molecular structure recombination on chemical materials.However,due to the limitations of traditional ceramic preparation processes,ceramic products used in industry often only have simple three-dimensional shapes.High-performance ceramic devices with complex micro-nano structures are not available.Combined with precursor conversion ceramic technology and high-precision additive manufacturing technology,it can not only achieve multi-level order regulation of micro-nano dimensional precision in ceramic physical structure,but also carry out multi-component molecular structure recombination on chemical materials to realize macro/micro / Nano view multi-scale material and structure design,to obtain a ceramic device with good thermomechanical properties,lightweight,multifunctional complex micro-nano structure.In this paper,the organic ceramic precursor materials suitable for photocuring 3D printing were studied.The addition of metal alkoxide and active filler effectively controlled the microstructure and controlled shrinkage of the material,and synthesized a new ceramic precursor with high curing strength,high photosensitivity and low viscosity.The photosensitive resin was printed by the digital light processing(DLP)3D printing technology.The complex octagonal lattice structure was printed.The SiOC ceramic samples with good mechanical properties and uniform shrinkage were obtained by cracking at 500-1200 ° C in a nitrogen atmosphere.The ceramics were studied in detail.Phase transition,microstructure,volume shrinkage,etc.during the process.The main contents of this article are as follows:The first,Zr,Ti co-doped organosilicon photosensitive resin was synthesized by sol-gel method.The lattice structure of different curing thickness(25/50/100 ?m)was successfully printed by DLP technology.The structure was obtained under different temperatures in nitrogen atmosphere.The complete and dense lattice structure SiOC ceramics has a volume shrinkage of 35% at 1200° C and a mass loss of 55%.As the cracking temperature increases,the mechanical properties of the lattice structure ceramics are significantly improved,the hardness is increased from 5.11 GPa to 7.61 GPa,and the elastic modulus is increased from 35.3 GPa to 62.1 GPa.The doped Ti and Zr are enriched in the nanocrystalline region of the ceramic matrix,which acts as a pinning effect and effectively improves the mechanical properties of the lattice structure ceramics.The second,the nano-titanium powder was successfully doped in the silicone photosensitive resin by ball milling.Due to the scattering and absorption of the nano-titanium powder,the depth of the transmission coefficient and the critical exposure value decreased significantly with the increase of the doping amount,and the doping amount was 0.05%.When the light intensity is 5mW/cm2,light-curing 3D printing can be realized,and the SiOC ceramic structure is dense after cracking under an inert atmosphere of 1000 °C.The volume of the sample before and after the cracking is about 40%,and the structure is complete after cracking without obvious defects.The doped Ti atoms are uniformly mixed in the lattice structure,and the mass fraction reaches 0.6 wt%.