注凝成型及其烧结工艺研究进展

科技的发展对材料的要求越来越高，传统的成型和烧结技术仅适用于小尺寸且形状规则的金属成型，且需要在一定的压力下才能达到足够高的力学性能。注凝成型技术适用于各种复杂形状、大尺寸部件的近净尺寸成型，具有实验设备简单、工艺过程易控制、坯体密度均匀、强度高等突出优点。为了制备出高固相含量、低黏度、高密度的金属陶瓷，分别从注凝成型工艺过程、注凝成型体系和烧结致密化方法等方面进行了研究。研究表明：注凝成型工艺过程主要分为球磨、凝胶、干燥、排胶和烧结；注凝成型体系分为水系凝胶和非水系凝胶；浆料的黏度对坯体的力学性能影响较大；干燥不当会导致坯体的开裂；烧结温度和烧结助剂对烧结体性能有较大的影响。

Research progress of gelcasting and sintering process

The development of science and technology has higher and higher requirements for materials. The traditional forming and sintering technology is only suitable for the forming of small-size and regular shape of metal, and high enough mechanical properties can be achieved only under a certain pressure. Gelcasting technology is suitable for the near net size molding of various complex shapes and large-size parts, and has the outstanding advantages of simple experimental equipment, easy control of the process, uniform density of the body and high strength. In order to prepare cermet with high solid content, low viscosity and high density, the gelcasting process, gelcasting system, and sintering densification method were studied. The results show that the process of gelcasting is mainly divided into ball grinding, gel, drying, dispensing and sintering. The gelcasting system can be divided into stream gel and non-stream gel. The viscosity of slurry has a great influence on the mechanical properties of the body. Improper drying will lead to the cracking of the body. Sintering temperature and sintering additives have great influence on sintering properties.