Ti3SiC2/SiC 复合材料原位制备技术及其组织、性能研究

【作者】 周晓龙；

【导师】 陈敬超；

【作者基本信息】 昆明理工大学 ， 材料学， 2001， 硕士

【摘要】 陶瓷材料的脆性限制了其应用的范围，而Ti₃SiC₂陶瓷材料由于其高温条件下具有较好的塑性行为，以及好的综合机械性能，从而被认为是最具有发展前景的韧性陶瓷，受到研究者的高度重视。但是由于制备纯相的Ti₃SiC₂陶瓷材料的工艺条件范围比较狭小，获得大尺寸的Ti₃SiC₂陶瓷材料很困难，因此，制备Ti₃SiC₂基复合材料成为利用Ti₃SiC₂陶瓷材料好的综合机械性能的一条途径。而固态置换原位反应以其制备方法简单、成本低廉等优点，成为制备Ti₃SiC₂基复合材料的首选制备方法。 本文采用原位热压技术来制备Ti₃SiC₂/SiC复合材料，一方面是为了更好的利用Ti₃SiC₂陶瓷材料好的综合机械性能；另一方面是为了研究固态置换原位反应反应机理、反应路径，以及界面反应机制对组织形貌的影响。而化学势稳定性相图是判断化学反应路径的有效工具，为了计算化学势稳定性相图，我们提出了一种简单估算中间化合物Gibbs生成自由能的方法——影射分解矩阵模型，并根据Ti-Si-C三元相图得到了各元素的化学势相图，得出了合成Ti₃SiC₂/SiC复合材料的反应路径。通过实验，我们获得了Ti₃SiC₂/SiC复合材料，且利用反应物C、Si的调控作用，制备出机械性能不同的Ti₃SiC₂/SiC复合材料，以满足不同的工作环境；由实验结果，探讨了合成Ti₃SiC₂/SiC复合材料固态置换原位反应机理，及界面的生长方式。 由实验结果发现，硅流失是造成化学反应不完全的主要因素，而硅的流失主要是由于温度与压力的影响，因此调整制备工艺，特别是调整温度与压力的关系对合成Ti₃SiC₂/SiC复合材料是必要的。更多还原

【Abstract】 Application of ceramic materials is confined for their brittleness. Ti3S1C2 ceramic is considered that has developing perspective material because it has good plasticity and comprehensive property at high temperature. However, synthesizing process rang is narrow in producing Ti3SiC2 ceramic and it is difficult to obtain Ti3SiC2 ceramic of large measurements. Therefor, Ti3SiC2-matrix composite is a better means for taking advantage of comprehensive mechanical property of Ti3SiC2 ceramic. Solid state displacement reactions are being as a better technique to produce Ti3SiC2-matrix composite in- situ by their merits of simple fabrication and low price. The paper adopts the solid state displacement reactions to synthesize in-suit composite of T13S1C2/SIC. The means is using good mechanical property of Ti3SiC2-matrix composite. Principle, reaction route and mechanism of the solid state displacement reaction are researched. Moreover, the diagram of chemical potential is an effective implement for judging route of chemical reaction, A simple mode of estimating Gibbs free energy of mid-compound mapping-decomposition hollow-square mode, which can calculate diagram of chemical potential, are put forward. The diagram of chemical potential about every element is obtained according to the ternary Ti-Si-C diagram. The reaction route of synthesizing Ti3SiC2/SiC composite is also gained. As a result of experiment, T13SiC2/SiC composites are attained. T13SiC2ISiC composites having the different mechanical properties for meeting condition of different work circumstance are fabricated by adjustment of raw material. In this paper the mechanism of in-suit reaction of a solid state displacement and method of interface grow are discussed. According to the results of experimenttr, the lost of silicon, whichis influenced by temperature and press, is a reason of no completereaction. Therefor, adjusting progress, especially relation oftemperature and press, is necessary to synthesize Ti,SiC,/SiCcompo site.更多还原