Changes in the phase composition and structure of electrodeposited Sn–Co alloys in Sn–Co/Cu layer systems upon heating

Autor: Ingrīda Vītiņa, Aija Krūmiņa, Velta Belmane, Valda Rubene
Rok vydání: 2011
Předmět:
Zdroj: Surface and Coatings Technology. 205:2893-2898
ISSN: 0257-8972
DOI: 10.1016/j.surfcoat.2010.10.054
Popis: Changes in the phase composition and structure of electrodeposited tin–cobalt (Sn–Co) alloy layers (5–10 μm) containing a limited quantity of Co (0.24, 2.4, 11.0, 17.0 or 26.5 wt.%) were studied using X-ray diffraction (XRD) and optical microscopy. The phase composition and coating structures of Sn–Co alloys in Sn–Co/Cu layers underwent considerable changes upon heating at 170 °C for 100–200 h and at 170 °C for 200 h followed by 205 °C for 20 h. The changes were dependent on the Co content in the alloy and the heating temperature. When examining the sample containing 11.0 wt.% cobalt, an unidentified phase containing a Sn–Co compound, CoSn 2 and CoSn 3 formed upon heating at 170 °C for 100, 140 and 200 h. The structure of the layer surface was composed of spherical crystallites. The formation of the unidentified phase possibly caused the formation of needle-shaped crystals in the structure consisting of spherical crystallites. When the Co content of the Sn–Co layer was increased to 17.0–26.5 wt.% and the sample was heated to 170 °C for 100–200 h, phases of CoSn, CoSn 2 , Co 3 Sn 2 and CoSn 3 were formed. The coating maintained its structure and was composed of spherical crystallites. In the Sn–Co/Cu system of layers containing 11.0, 17.0 or 26.5 wt.% Co, Sn–Cu intermetallic compounds (Cu 6 Sn 5 and Cu 3 Sn) did not form after heating at 170 °C for 200 h followed by 205 °C for 20 h.
Databáze: OpenAIRE
Externí odkaz: