光固化3D打印SiC:粉体氧化处理提升浆料UV固化性能

3D printing of silicon carbide ceramics based on photopoymerization:Surface oxidation of SiC powder to improve UV curing property of its slurry

为了进行碳化硅(SiC)的光固化3D打印,本文提出采用表面氧化处理提升SiC浆料的光固化性能。采用扫描电子显微镜、X射线衍射仪、X射线光电子能谱等研究了SiC颗粒的氧化过程以及氧化温度与保温时间对氧化过程的影响;采用动态流变仪、紫外分光光度计、数字千分尺等研究了浆料的流变性能和光固化性能。结果表明:经表面氧化处理后的SiC颗粒紫外反射率有显著的提高,最高为48.11%,为未氧化SiC颗粒的1.8倍;配制的浆料光固化性能有明显的改善,曝光5 s时固化厚度最高为76μm,为未氧化的3.6倍。随着氧化温度的上升以及保温时间的延长,氧化层厚度持续增长,最高达到144.8 nm。考虑到过度氧化不利于后续SiC陶瓷的烧结成型,最终选择使用1100℃保温3.0 h的氧化SiC粉末,并以1%(质量分数)的KOS163为SiC浆料的分散剂,制备了固含量为45%(体积分数)的SiC浆料,成功实现了SiC陶瓷坯体的光固化3D打印。

In order to prepare SiC ceramics by 3D printing based on photopolmerizaiton,the surface oxidation treatment was proposed to enhance the UV curing property of SiC slurry.The oxidation process of silicon carbide particles,the effects of oxidation temperature and holding time on the oxidation process were analyzed by SEM,XRD and XPS.The rheological and UV curing properties of SiC slurry were analyzed by a dynamic rheometer,an UV spectrophotometer and a digital micrometer.The results show that the UV reflectivity of SiC particles after surface oxidation treatment is significantly improved,up to 48.11%,which is 1.8 times of that of the non-oxidized SiC particles.The UV curing performance of the slurry is obviously improved.Its curing thickness is up to 76μm as the slurry is exposed under UV light for 5 s,which is 3.6 times of that of the non-oxidized SiC particles.The thickness of the oxide layer increases with oxidation temperature and holding time,up to 144.8 nm.Considering that excessive oxidation is not conducive to the subsequent sintering process for silicon carbide ceramics,the optimal process for surface oxidation of SiC powder is holding at 1100℃for 3.0 h.The slurry with 1%(mass fraction)KOS163 as a dispersant and a solid content of 45%(volume fraction)is successfully printed into 3D SiC ceramic body via 3D printing based on photopolymerization.