铜磷钎料热加工过程表观变色机理研究

Study on the Apparent Discoloration Mechanism of Copper-phosphorus Solder during Thermal Processing

针对铜磷钎料热挤压酸洗后表面出现的色差现象,以未酸洗BCu93P铜磷焊丝为研究对象,对焊丝截面分别进行XRD、SEM、EDS等分析,对焊丝表面进行XPS测试。XRD分析表明,钎料内部合金主要由Cu和Cu_(3) P两相组成。SEM和EDS分析表明,钎料内部(Cu+Cu_(3) P)共晶组织分布均匀,无元素偏析。钎料内部主要为Cu和P两种元素;钎料表面主要为Cu、P、O三种元素。色差主要出现在焊丝表面,未对钎料内部合金相组成产生影响。热挤压后,钎料表面有片状不连续氧化膜。XPS分析表明,正常钎料表面Cu_(2)O含量高,约为38.9%,P含量低,约为1.79%;变色钎料表面Cu_(2)O含量低,约为24.5%,P含量高,约为11.82%,有新相CuP_(2)的形成。铜磷钎料热加工过程中丝材表面的不均匀氧化是出现色差的根本原因。

In response to the color difference phenomenon on the surface of copper-phosphorus brazing wire after hot extrusion pickling,the unpickled BCu93P copper-phosphorus wire was studied,and XRD,SEM and EDS analyses were performed on the cross-section of the wire,and XPS tests were performed on the surface of the wire.XRD analysis shows that the internal alloy of the brazing material is mainly composed of two phases namely Cu and Cu_(3) P.SEM and EDS analysis result show that the internal(Cu+Cu_(3) P)eutectic organization of the brazing material is uniformly distributed,and there is no elemental segregation.The internal brazing material is mainly composed of Cu and P;the brazing material surface is mainly composed of Cu,P and O.The chromatic aberration mainly appeared on the surface of the brazing wire and did not affect the internal alloy phase composition of the brazing material.After hot extrusion,the surface of brazing material had flaky discontinuous oxide film.XPS analysis results show that the normal brazing material normal brazing material surface has high Cu_(2)O content,about 38.9%,and low P content,about 1.79%;the discolored brazing material surface has low Cu_(2) O content,about 24.5%,and high P content,about 11.82%,with the formation of new phase CuP_(2).The uneven oxidation of the wire surface during the thermal processing of copper-phosphorus brazing material is the root cause of the color difference.