表面原位生长晶须对陶瓷的润湿性及其与金属钎焊的影响机理研究

Based on the requirement of interfacial reaction control and stress release of the ceramic and metal brazed joint, the method to enhance the joining quality between ceramic and metal by using in situ growth of whiskers on the surface of the ceramic substrate was raised. The formatioin of continuous reaction layer in the ceramic side was avoided by the in situ grown whiskers. At the same time, the physical properties of brazed seam were modified and the gradient transfer of the joint was realized, which led to the increase of the joining quality. According to the control of interfacial reaction and stress, the in situ grown process and mechanism of the whisker was investigated. The joining of ceramic was realized using in situ growth of whiskers. The joining mechanism between in situ grown whiskers and ceramic substrate was clarified. The effect of the in situ grown whiskers on the wetting ability of ceramic was systematically investigated. Based on the stress analysis, the optimal design of composite filler metal system can be realized. The evolution of the interfacial reaction was clarified. The reaction models of all interfaces in the joint were established. The influence of the interlayer reaction products on the joint properties is analyzed. The joining mechanism of the joint was clarified. The objective of this project is to extend the application of the whisker materials in the joining fields, enlarge the based theory on joining between single-crystal and polycrystalline materials and promote the development of the joining technology between ceramic and metal.

本项目针对陶瓷与金属钎焊界面反应控制和应力缓解的要求，提出了利用陶瓷表面原位生长晶须辅助提高陶瓷与金属连接质量的方法，利用原位生长的晶须避免陶瓷侧连续反应层的生成，同时调节钎缝的物理性能实现接头性能的梯度过渡以提高连接质量。本项目以界面反应和应力控制为研究切入点，重点研究陶瓷表面晶须的原位生长工艺与机理，同时利用原位生长的晶须直接实现陶瓷的连接，阐明原位生长的晶须与陶瓷母材的连接机理。系统研究表面原位生长晶须对陶瓷润湿性的影响规律，基于接头的应力分析实现复合钎料体系的优化设计，阐明接头的界面组织演化规律，建立接头内各界面的反应模型，揭示界面反应产物与连接性能的对应关系，阐明接头的连接机理。本项目旨在推广晶须材料在连接领域的应用，丰富单晶材料与多晶材料连接基础理论，促进陶瓷与金属连接技术的发展。

本项目针对陶瓷与金属钎焊界面反应控制和应力缓解的要求，提出了利用陶瓷表面原位生长晶须辅助提高陶瓷与金属连接质量的方法。本项目以界面组织调控和应力缓解为研究切入点，重点研究陶瓷表面晶须的原位生长工艺与机理，利用粉末原料成功在Al2O3陶瓷和NiAl合金表面原位生长出晶须，研究了原料成分和生长工艺对晶须形貌的影响规律，分析了晶须成分、晶体结构及生长特性，探讨了晶须生长机理，在Al2O3陶瓷表面所得晶须950℃以下为Al4B2O9相、1050℃以上为Al18B4O33相，在NiAl合金表面生长的晶须为Al4B2O9和少量Ni3(BO3)2。利用表面生长晶须对Al2O3陶瓷进行了直接连接，研究了中间层成分及连接工艺参数对所得接头组织形貌及高温强度的影响，分析了接头的连接机理。1100℃/4h条件下所得接头800℃高温抗弯强度最高(27MPa)，断裂发生在晶须内部。同时，探索了采用溶胶凝胶法连接Al2O3陶瓷、晶须直接连接MgO陶瓷以及利用ABS微晶玻璃中间层连接ZTA陶瓷，均取得了较好效果。分析了表面生长晶须对Al2O3陶瓷表面润湿性的影响，发现在真空条件下，含有活性元素的AgCuTi钎料能够润湿生长有晶须的陶瓷表面，液态钎料在该表面的润湿为反应润湿，晶须间的毛细作用可以促进液态钎料的铺展。以AgCuTi为中间层对生长晶须的Al2O3陶瓷进行了真空钎焊，研究了钎焊工艺参数对接头微观结构及机械性能的影响规律。此外，采用Ag基钎料成功实现了生长晶须的Al2O3陶瓷与TC4钛合金及与表面生长晶须的NiAl合金的连接，晶须存在于钎缝中，实现了接头物理性能的梯度过渡，进而提高了接头连接质量。本项目应力缓解与接头组织控制思想拓展应用到了多种陶瓷与金属等异质材料连接中，有助于推广晶须材料在连接领域的应用，促进异质材料连接技术的发展。