The Evaluation of Sn-58Bi Composite Solder Mixed with Y2O3

With the development of surface mount technology, solders are required for applications that require high reliability and dimensional stability. Composite solders reinforced with particles in a conventional solder alloy, is an attractive and potential method. This study presents series results on the binary eutectic Sn-Bi composite solders reinforced with Y₂O₃ particles from 0 to 3%. With this process, the reinforcement particles are well dispersed in the solder matrix and depress the growth of IMC layer. The gray impurities on the surface of the Sn-Bi solder cap are estimated to be Bi₂O₃ by XRD. With the increase of Y₂O ₃ content, the surface of the solder cap gets brighter and the number of fine particles mainly made up of Y₂O₃ and Bi₂O₃ around the solder joints increases. The wetting properties and the shear strengths of solders are improved by the addition of Y₂O₃