激光增材制造用SiC粉末制备及成形工艺探索

Study on preparation and forming process of SiC powder for laser additive manufacturing

为制备高强度复杂形状SiC陶瓷零件,以酚醛树脂(PF)为粘接剂,分别采用机械混合法(SPM)和搅拌蒸发法(SPC)制备两种SiC复合粉末,并对两种粉末进行了SEM电镜扫描、SLS成形、碳化和渗硅反应烧结处理.研究表明,在激光功率10 W,分层厚度0.1 mm,扫描速2 000 mm/s,扫描间距0.2 mm时,SLS坯体密度大(1.259 g/cm3),生产效率高.利用SPC粉末制得的SLS坯体内部孔隙更多,碳化和渗硅烧结后坯体密度明显增加.采用SPC粉末所制零件最终力学性能更好,更适于生产.在最优工艺条件下,制备了复杂形状的高性能SiC零件.

To fabricate SiC parts with high performance and complex structure,Phenol-formaldehyde resin（PF）was applied as adhesive,SiC-PF mixing powder（SPM） and SiC-PF Coating powder（SPC） were prepared by mechanical mixing and stirring evaporation method. SEM analysis, Selective Laser Sintering（SLS）,carbonization and siliconizing process were carried out to characterize the formation of these two materials. The results indicated that the powder fabricated by SLS had high body density and production efficiency when the laser power,layer thinkness,scanning speed and hatch spacing were respectively set at 10 W,0. 1 mm,2 000 mm/s and 0.2 mm. It was found that the body formed by SPC powder had more micro pores and the body density increased apparently after carbonization and siliconizing process. SPC parts have higher density and it is more suitable for production. Complex ceramic parts were fabricated under the optimum process conditions.