Oxidation and wetting characteristics of lead-free Sn-0.7Cu solder alloys with the addition of Fe and Bi
Document Type
Article
Publication Date
12-1-2022
Abstract
In this paper, the oxidation and wetting behaviour of Sn-0.7Cu and Sn-0.7Cu-0.05Fe-2Bi solder alloys has been investigated. The alloys were subjected to 200 degrees C in oxygen rich environment. Weight gain curves reveal that the oxidation behaviour obey the parabolic rate law. X-Ray photo electron spectroscopy (XPS) reveals the presence of SnO and SnO2 oxide layer on the surface of Sn-0.7Cu solder alloys. SnO was formed as the basic oxide layer. However, at higher temperature SnO transforms into SnO2. Addition of Bi results in the formation of Bi2O3. The Pilling-Bedworth ratio of SnO, SnO2 and Bi2O3 oxides are 1.28, 1.35 and 1.23 respectively. These ratios confirm the passive nature of oxide layers. Wetting behaviour of Sn-0.7Cu and Sn-0.7Cu-0.05Fe-2Bi were investigated on Cu substrate. The addition of Bi and Fe improves the wetting properties of Sn-0.7Cu solder alloys. Alloying with Bi and Fe results in growth suppression of intermetallic compound at the interface. Increase in spreading rate, decrease in wetting angle and solder height reveals better performance of the Sn-0.7Cu-0.05Fe-2Bi solder alloy.
Keywords
Sn-0, 7Cu alloy, Fe and Bi alloying, Oxidation behaviour, X-ray photoelectron spectroscopy (XPS), Wetting behaviour
Divisions
fac_eng
Funders
Universiti Malaya [RP003A/13AET] [PG025-2015B]
Publication Title
Microelectronics Reliability
Volume
139
Publisher
Elsevier
Publisher Location
THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND