Effects of Phosphorus on Microstructure and Fluidity of Sn-0.7Cu-0.05Ni Lead-Free Solder

Autor:	J. Read, Christopher M. Gourlay, Tetsuro Nishimura, Arne K. Dahle, Kazuhiro Nogita, Shoichi Suenaga
Rok vydání:	2008
Předmět:	Materials science Mechanical Engineering Phosphorus Alloy Metallurgy Intermetallic chemistry.chemical_element engineering.material Condensed Matter Physics Microstructure Nickel chemistry Mechanics of Materials Soldering Volume fraction engineering General Materials Science Eutectic system
Zdroj:	MATERIALS TRANSACTIONS. 49:443-448
ISSN:	1347-5320 1345-9678
DOI:	10.2320/matertrans.mbw200713
Popis:	Phosphorus is often added to wave-solder baths as an anti-oxidation agent. Despite this practice, there is little information on how phosphorus influences the solidification and flow properties of new lead-free solders such as Sn-0.7Cu-0.05Ni. This paper investigates the effects of phosphorus content on microstructure and maximum fluidity length in Sn-0.7Cu-0.05Ni-xP alloys containing 0-0.08 mass% phosphorous. Ppm levels of phosphorous are found to cause Sn-JrP, Ni-xP-(Sn) and Cu-xP-(Sn) intermetallic compounds to form in the liquid solder. The IMCs are less dense than liquid Sn and float towards the surface of the melt driven by buoyancy. It is shown that P-free Sn-0.7Cu-0.05Ni solidifies with a near-eutectic microstructure whereas, when P is added to this alloy, a significant volume fraction of primary Sn dendrites form once the P content exceeds ∼0.01 mass% P. It is further shown that P additions decrease the ability of Sn-0.7Cu-0.05Ni to flow as it solidifies.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b28dd69d250400741597e34ca94e1b24 https://doi.org/10.2320/matertrans.mbw200713 Zobrazit plný text záznamu