双连续结构多组元复合材料及其腐蚀介质冲蚀行为研究

Early failure of materials due to erosion and corrosion is often encountered in chemical industry and military field such as wet-process metallurgy and Carrier-based planes. The problem has hindered development of technology and new materials should be researched to service under erosion and corrosion environment. In this project based on composite, erosion and corrosion theories a new type composite is designed. In this new type composite three-dimension porous metal is used as framework, polymer as binder phase and ceramic as reinforced phase. The new composite possesses good impact resistance since stresses contrated on a point can disperse and diliver quickly in the composite. Meanwhile, this structure is beneficial to adhesive strength among different components. This new type composite will be prepared by the process of vacuum injection and harden molding. The process parameters must be optimized through a lot of experiments. Failure process of the new composites due to impacting of solid or liquid particles can be simulated by ejection erosion tests or cavitation erosion tests. The influence of concentration of corrosive medium, temperature and flow rate on damage of composites will be studied. Electrochemical measurement, tribological experiments and modern analysis technologies will be combined to develop failure process and law of new composites under erosion, corrosion and erosion corrosion conditions. The synergetic action of different components in the new composites will be explored in this project. It will bring evolution of erosion and corrosion theories of composites and provide guidance of selecting materials for using under erosion and corrosion conditions.

在湿法冶金等化学工业和舰载机等军用领域经常会遇到材料在冲蚀和腐蚀共同作用下过早失效的问题，并且已经成为技术发展中的瓶颈。本项目拟从冲蚀、腐蚀理论和复合材料学出发设计一种具有三维增强模式的双连续结构多组元复合材料，它以三维网状金属为骨架，聚合物为填充粘结相，陶瓷微粒为增强相，其优势在于可将冲击能量迅速在空间体范围传递、增加不同组元间的结合强度、提高腐蚀防护能力。采用射流冲蚀试验机和空蚀试验机模拟材料在固体颗粒和液滴冲击下的失效过程，考查不同腐蚀介质浓度、冲击速度、温度等因素对材料损伤的影响。把电化学测试、摩擦学实验和现代分析手段相结合，研究复合材料在腐蚀、冲蚀、腐蚀冲蚀条件下的损伤失效过程和规律，探索复合材料各组元间的协同作用机制，丰富复合材料的冲蚀、腐蚀理论。开拓真空吸注固化成型的制备手段，优化工艺参数，为腐蚀介质冲蚀使役环境中复合材料的设计和选择提供指导。

过程工业中的过流部件如管、阀、泵等不可避免地受到固、液、气等多相流的冲蚀作用，有时还伴随着酸、碱、盐等介质的腐蚀作用。此外，核电设施中的换热管路及舰载机的涡扇发动机也受到腐蚀和冲蚀共同作用。本项目针对以上工程背景，设计一类新型复合材料，从各组元成份选择上解决耐腐蚀问题，从材料整体结构上解决耐冲蚀问题，使材料同时具有良好的化学与力学性能。. 本项目开展了双连续复合材料的选材与制备工艺研究：选择集结构与功能一体化的泡沫镍基材料为第一个连续相，通用型热固性环氧树脂、聚氨酯或热塑性聚醚醚酮为第二个连续相，与金属相在空间形成双连续结构。具有高硬度、高耐磨性、耐腐蚀性能的陶瓷粉碳化硅作为树脂增强相，硅烷偶联剂KH-550为泡沫金属和陶瓷粉的表面有机化改性剂。采用真空吸注工艺制备出泡沫镍（镍铬）/环氧树脂（聚氨酯）/碳化硅复合材料，采用模具热压工艺制备出泡沫镍（镍铬）/聚醚醚酮复合材料。. 对所制备复合材料的结构和力学性能进行表征和分析：对复合材料界面、形貌和冲击断口的表征发现，树脂在泡沫金属孔洞中填充良好，硅烷参与树脂的固化反应，在树脂、金属相间形成过渡层，提高了界面结合强度。复合材料的力学性能与金属相的孔径、孔隙率及树脂相的成份密切相关，其冲击强度优于单一树脂相，最高的可提高5倍以上；其拉伸强度略低于单一树脂相，原因是材料拉伸断裂从整体损伤模式向裂纹扩展模式转变。. 对所制备复合材料的空蚀、料浆冲蚀行为进行评价：复合材料的空蚀失重高于单一树脂相，其冲蚀体积损失低于单一树脂相；在稀盐酸中腐蚀与空蚀之间存在明显的交互作用，交互作用引起的失重约占总失重的50%，在NaCl溶液中腐蚀与冲蚀之间的交互作用量较小且为负值；合理匹配泡沫金属骨架的孔径和体密度，能够有效地吸收并传递表面的冲击载荷和能量，制备出复合材料的抗冲蚀性能可以提高2-4倍。. 本项目工作为耐腐蚀介质冲蚀材料的研发，提供了新思路，探索了新方法，积累了有重要价值的基础数据。