采用Ag-Cu-In-Ti焊料连接碳化硅陶瓷

Brazing of SiC Ceramics Using Ag-Cu-In-Ti Filler Metal

采用四元Ag-Cu-In-Ti焊料成功地连接了常压烧结SiC陶瓷.研究了钎焊温度和保温时间对碳化硅连接强度的影响,同时通过EPMA和TEM分析连接界面的微观结构,并且探讨了连接的原理.试验结果表明,在700～780℃试验温度范围内,碳化硅的连接强度存在峰值,最高四点弯曲强度达到了234MPa,但是连接强度随着保温时间的增加呈现单调下降趋势.接头微观结构由基体SiC、反应层和焊料三部分组成,连续致密的反应层紧密连接基体和焊料,反应层由带状层、TiC层和Ti5Si3层组成,带状层宽度约20nm,由Ag、In、Si和少量的Ti、Cu组成.元素线扫描结果显示焊料中的活性元素Ti含量在反应层内形成峰值,活性元素Ti与SiC发生反应生成新的反应层是连接的主要因素.

Sintered silicon carbide was jointed with itself using Ag-Cu-In-Ti filler metal successfully.Interfacial microstructure was investigated by electron probe microanalysis （EPMA） and transmission electron microscope （TEM）.Joining strength of SiC/SiC joints was measured by four-point flexural strength.The experimental results indicate that joining strength has a peak value with the joining temperature increasing,and the max flexural strength reaches 234MPa,however joining strength decreases monotonously with the holding time increasing.The interface of joints is composed of three parts： SiC substrate,reaction layer and filler metal.The continuous and compact reaction layer which is composed of strip layer,TiC layer and Ti5Si3 layer,combines the SiC substrate and filler metal tightly.The strip layer consisting of Ag,In,Si,Cu,Ti and C elements is about 20nm in thickness.The elemental linescanning result shows that nearly all the active element Ti concentrate in the reaction layer and the main reason for the joining is the reaction between Ti and SiC.