摘要
通过定向冷冻、冷冻干燥和高温烧结制备了具有定向层状孔隙的SiC多孔预制体,研究了浆料球磨时间、SiC粉料粒径、定向冷冻时间和冷冻干燥过程对预制体制备工艺的影响,确定了合适的定向冷冻干燥制备工艺。结果表明:SiC粉料在液相中充分地分散、润湿和形成水化膜后可以获得性能稳定的浆料,三种SiC粉料(初始粒径1. 8μm、9. 0μm和17. 4μm)的球磨时间应分别大于12 h、14 h和20 h;定向冷冻过程中冰晶的生长和陶瓷颗粒的重排与SiC颗粒大小有着密切的关系,采用粒径1. 8μm粉料制备的预制体中层状孔隙定向性和连通性最好;固相含量较低的浆料要采用较长的冷冻时间;虽然冷冻干燥温度较高时失重速率较高,但低温更有利于保持冰晶形貌,因此可选用定向冷冻温度作为冷冻干燥温度,冷冻干燥时间应不少于24 h。
Silicon carbide scaffolds for metal-matrix composite with directional lamellar micro pores were prepared by directional freeze casting,freeze drying and sintering process.The influence of milling time of slurry,SiC particle size,directional freezing time and freezing drying process on preparation process of SiC scaffolds was investigated,and the appropriate preparation process using directional freezing drying method was developed.The results show that the stable slurry can be gotten after the SiC particles are fully dispersed and wetted in the liquid phase and the hydrated films are formed.The milling times of three kinds of SiC powders(initial particle size 1.8μm,9.0μm,and 17.4μm)should be greater than 12 h,14 h,and 20 h,respectively.There is a strong link between the growth of ice crystals,rearrangement of ceramic particles and the SiC particle size.The scaffolds prepared by 1.8μm SiC powders have pores with the best orientation and connectivity.Longer freezing time should be adopted for slurry with lower solids loading.The weight loss rate is higher when the freezing drying temperature is low,but the low temperature will help to maintain the morphology of ice crystals,so the freezing drying temperature can adopt the freezing casting temperature and the freezing drying time should not be shorter than 24 h.
作者
刘洪军
李晓雪
刘长志
李亚敏
LIU Hong-jun;LI Xiao-xue;LIU Chang-zhi;LI Ya-min(State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China)
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2018年第11期3433-3437,共5页
Bulletin of the Chinese Ceramic Society
基金
甘肃省高校基本科研业务费(2014-14)。
关键词
定向冷冻
冷冻干燥
SIC
多孔陶瓷
定向层状孔隙
directional freezing
freezing drying
SiC
porous ceramics
directional lamellar micro pores
