以Ag-CuO-B2O3为钎料, 采用空气反应钎焊法连接了Al2O3陶瓷, 在接头中合成了新型Cu2Al6B4O17晶须。研究了连接温度与保温时间对接头显微结构、性能以及生成的晶须结构的影响。结果表明: 钎焊过程中, Al2O3与钎料中的CuO、B2O3发生反应生成Cu2Al6B4O17晶须, 获得性能优异的可靠接头。保温时间为60 min、连接温度高于950 ℃时, 可以实现Al2O3陶瓷接头的有效连接, 钎缝中心区主要为Ag, 靠近连接界面处为CuO、Cu3B2O6相及Cu2Al6B4O17晶须。随着连接温度的升高, 接头的抗剪强度升高。连接温度高于1 050 ℃后, 晶须变得粗大, 出现黏接, 对接头的强化效果减弱, 接头的抗剪强度降低。连接温度高于1 100 ℃后, 晶须分解为片层状产物, 接头的抗剪强度大幅降低。最佳工艺参数为在1 000 ℃条件下保温60 min, 接头的抗剪强度可达86.7 MPa, 断裂发生在焊缝中靠近母材处。

Alumina ceramics were joined with Ag-10CuO-10B2O3 filler via reactiver air brazing for the formation of whiskers (Cu2Al6B4O17) in the joints. The effects of brazing temperature and holding time on the microstructure, properties of the joints and the whisker structure were investigated. The results show that Al2O3 reacts with CuO and B2O3 to form Cu2Al6B4O17 whiskers in the brazing process, thus obtaining a reliable joint with the superior performance. At the holding time of 60 min and the brazing temperature of > 950 ℃, an effective connection of Al2O3 ceramic joint can be realized. The center area of the brazing joint is mainly Ag, while the interface at the both sides of the joint is composed of CuO、Cu3B2O6 phase and Cu2Al6B4O17 whiskers. The shear strength of the joint increases with the increase of the brazing temperature. The whiskers become thick and the adhesion occurs when the brazing temperature is > 1 050 ℃, thus reducing the strengthening effect on the joint and the shear strength of the joint. The whiskers decompose into some lamellar products, and the shear strength of the joint decreases when the brazing temperature is > 1 100 ℃. The shear strength of the joint prepared under optimum process parameters (i.e., at 1 000 ℃ for 60 min) can reach 86.7 MPa, and the fracture occurs in the weld nearby alumina ceramic base material.