陶瓷材料的SHS超快速致密化技术

自蔓延高温合成(self-propagating high-temperature synthesis,SHS)是一种在数秒～几十秒内即可完成的合成技术,但是直接产物是多孔状的.在SHS产物还处于高温软化状态时立即快速加压(quick pressing,QP),可以一步实现合成和致密化获得致密材料,这一技术被称为SHS/QP技术.传统的高温烧结的致密化过程主要靠原子扩散实现,SHS/QP过程如此之快,其致密化机理尚不明确.为此,探讨了SHS/OP技术制备金属陶瓷和复相陶瓷的致密化机理.研究了SHS/OP技术制备金属陶瓷、复相陶瓷和叠层复合材料的结构和工艺过程,并制备了密实材料.结果表明:基于塑性变形机理,SHS/QP技术能制备出密实、晶粒基本不长大的纳米陶瓷.

PROCESS FOR SHS ULTRA-FAST DENSIFICATION OF CERAMICS

Combining self-propagation high-temperature synthesis (SHS) with hydraulic quick pressing (QP) in a single processing operation, dense ceramics can be fabricated rapidly. Immediately after SHS, when the sample is still red-hot and soft, a quick and large mechanical force is applied to the sample. The densification of the sample can be achieved in several minutes. The mechanism of densification in such a short time is still not clear. In this paper, the SHS/QP densification mechanism for ceramics is discussed. The processes for the making of multi-phase ceramics, layered materials and nano-ceramics were studied. The results show that dense ceramics with finer grains can be obtained by the SHS/QP technique. The process also revealed the densification mechanism based on plastic deformation.