Microstructure, Interface Morphology, and Antioxidant Properties of Sn-8.5Zn-0.1Cr-(Nd,Al,Cu) Solders
文摘
The effects of minor alloying element Nd, Al or Cu on the fundamental microstructural properties, interface morphology, and antioxidant properties of Sn-8.5Zn-0.1Cr (SZC) alloy have been investigated. Addition of Nd, Al or Cu element significantly refined the microstructure of SZC alloy, especially promoting disappearance of the stripe Zn-rich phase. Precipitated phases could be found in the β-Sn matrix when the content of each element reached 0.1 wt.%. During soldering, it was found that Nd, Al or Cu element addition did not contribute to intermetallic compound (IMC) formation, as verified by the same IMC phase as at the Sn-8.5Zn/Cu interface and no obvious influence on interface morphology. After 15 days of aging, IMC interface layers increased severely and a wide Zn-poor transition zone formed. The growth rate of IMC was reduced and the transition zone became narrower after microalloying. Meanwhile, addition of Al or Cu element improved the oxidation resistance of the SZC alloy, while Nd-containing alloys oxidized severely. The wettability and microhardness of the SZC-xM alloys were superior to those of SZC alloy.