Ag-CuO纳米钎料可控合成及其钎焊Al2O3陶瓷工艺与机理研究

Owing to the improving demand of complex process (Mo-Mn method) and poor stability and high equipment requirements (Active-Metal Brazing) in brazing ceramics, Metal-Metal oxides nano-brazing filler is proposed combined with Nanotechnology. Taking Ag-CuO brazing filler as the research object, Alumina ceramics can be joined reliably based on the study of the controllable synthesis and the brazing process and mechanism of nano-brazing filler. The project takes the controllable synthesis, interfacial structure and joining mechanism as the key point, the reaction mechanism of Ag-CuO nano-brazing fillers on brazing of Alumina was studied in particular. The wetting process of Ag-CuO nano-brazing fillers and the evolution rule of interfacial structure were explored, and the formation mechanism of interface reaction phases was revealed, and then, the effect mechanism of nano-brazing fillers on the interfacial reaction and the growth of reaction phases was studied deeply. Finally, the relationship among nano-brazing fillers, interfacial microstructure and mechanical properties was obtained. The project aims to integrate ceramics brazing and nanotechnology, which provides theories and technologies for the breakthrough of ceramics joining, and then promotes the application of nanotechnology in the field of materials joining.

针对陶瓷钎焊连接中工艺流程复杂（Mo-Mn法）和钎焊稳定性差和设备要求高（活性钎焊法）的改善需求，结合纳米技术，提出了金属-氧化物纳米钎料钎焊氧化铝陶瓷的方法。以Ag-CuO钎料为研究对象，通过纳米钎料的可控合成、钎焊工艺及机理的研究，实现氧化铝陶瓷在空气气氛下的可靠连接。本项目以研究纳米钎料的合成、接头界面结构和连接机理为切入点，重点研究纳米钎料在氧化铝陶瓷钎焊中的作用机理；探究纳米钎料的润湿铺展行为；阐明接头界面组织演化规律；揭示界面反应相形成机制；确定纳米钎料对界面反应及反应相生长行为的影响机理；获得纳米钎料-界面组织-力学性能的对应关系。本项目旨在将陶瓷钎焊与纳米技术进行交叉融合，为陶瓷连接技术突破提供理论基础和技术支持，推广纳米技术在材料连接领域的应用。

本项目针对陶瓷钎焊连接中工艺流程复杂（Mo-Mn法）和钎焊稳定性差和设备要求高（活性钎焊法）的改善需求，结合纳米技术，提出了金属-氧化物纳米钎料钎焊氧化铝陶瓷的方法。通过水热方法实现了纳米CuO的可控合成并在此基础上制备了Ag-CuO(nano)钎料，与机械混合方法制备的Ag-CuO(micro)钎料相比两者的熔化特性之间没有明显差异。采用纳米钎料实现了Al2O3陶瓷之间的高质量的钎焊连接，接头典型界面微观组织为：Al2O3/CuAl2O4/Ag(s,s)+CuO/CuAl2O4/Al2O3；其接头强度最高可达121.79MPa，相比于采用微米钎料获得的接头提升幅度达到了20.5%。明确了典型的钎焊接头界面微观组织，完成了对不同钎料成分、钎焊工艺参数下的界面组织演化规律和界面反应机制的分析；并通过横向对比试验确定了钎料中CuO的尺度对界面微观组织和接头力学性能的影响，结果表明当采用纳米尺度的CuO时，填料中的L1液相更倾向于富集在陶瓷表面，有益于提升接头的力学性能。向Ag-CuO钎料中添加金属Pt进行改性，研究了Pt添加量对钎料熔化特性、界面微观组织及接头力学性能的影响；完成了Pt添加对Ag基钎缝的增强，Al2O3陶瓷钎焊接头残余应力的缓解作用及机理的分析。结果表明，在钎料中添加Pt可以改善Al2O3陶瓷与钎缝之间的热膨胀系数匹配，可以降低残余应力从而提升接头的力学性能；但由于Pt对Ag基钎缝存在固溶强化作用，过高的Pt添加量会导致钎缝的塑形变形能力下降，对接头的力学性能不利。在本项目中将陶瓷钎焊与纳米技术进行了交叉融合，为陶瓷连接技术突破提供了理论基础和技术支持，具有较高的科学意义。