| 摘要 |
The present invention is a technological sequence which is composed of uniaxial freezing with control solution composition, followed by freeze-drying, followed by sintering, and followed by infiltration. The invention enables the manufacturing of functionally graded composites. These composites can include spatially distributed phases of ceramics, metals, polymers, glasses, and their combinations as long as the composite matrix material is originally in the form of powders. During uniaxial freezing, the diameter of crystals growing from the suspension (and, thus, the diameter of the voids formed after freeze-drying) is dependent on the controllable rate of cooling, pressure and the changeable chemical composition of the suspension liquid phase. Thereby a structure with conic voids can be created. After following sintering and infiltration, the produced composite (e.g., ceramic-metal composite) will have a specially distributed concentration of the second phase in the composite matrix, that is, it will have a functionally-graded structure. |
