高温陶瓷复合材料的进展

DEVELOPMENT OF HIGH TEMPERATURE CERAMIC COMPOSITES

根据1800℃以上高温的使用要求,评述了结构陶瓷和陶瓷基复合材料(CMC)的目前状况和高温特性的局限性。分析和讨论了发展高温陶瓷复合材料的某些途径。重点介绍了微米和纳米复合材料,并简单介绍了功能梯度材料(FGM)。在1204~1371℃能可靠应用、成本适当的陶瓷和陶瓷复合材料的发展正受到重视。从目前看,1600℃以上和空气中应用最有希望的似乎是氧化物/氧化物系统,即氧化物纤维增强氧化物。SiC/SiC和SiC/Si_3N_4复合材料仍然是当前所关注的研究重点。高温蠕变速率问题的解决寄希望于适当的复合晶体结构。发展超强、超韧陶瓷的一个新的构想也许是微米和纳米复合工艺结合制造复合材料。

State-of-the art and property limitation of advanced structural ceramics and ceramic matrix composites (CMC) designed for use at high temperatures(1600℃) are reviewed. Some approaches for developing the ceramic composites used at temperature 1600℃ are analyzed and discussed. Ceramic micro-and nano-composites are discussed in detail, and functionally gradient materials. (FGM) are also briefly described. Development of reliable and cost--effective monolithic ceramics and ceramic composites at 1204～1371℃ has attracted much attention. From the state-of-art, it seemsⅠthat the most promising candidate material for use above 1600℃ is oxide/oxide system, oxide fiber reinforced oxide matrix composites. SiC/SiC and SiC/Si_3N_4 composites are still the focus of interest in the research field. Materials with high creep resistance at high temperature may be for the alloy with suitable complex crystal Structure, such as Al_2O_3/YAG (yttrium aluminum garnet) unidirectional eutectic, and it may be not need to develop materials.based on single crystal fibers. A new concept for developing ceramic materials with very high strength and fracture toughness is perhaps the combination of micro-and nano-composites, i.e. to developplatelet-reinforeed nanocom- posites, whisker-reinforeed nanocomposites and long fiber-reinforced nanocomposites, and these composites mayalso be used at high temperatures.FGM may be a strong competitor for some thermal protection applications, this technique not only can develop new materials but improve the performance of traditional materials as well.