The Correlation between the Liquid Structure and the Viscosity of Sn-Cu Lead-Free Solders


Article Preview

The liquid structure of two lead-free solder Molten alloys, Sn-0.5Cu and Sn-1.8Cu (wt.%), has been examined using X-ray diffraction method. The main peak for liquid structure of Sn-0.5Cu is similar to that of pure Sn. A pre-peak has been found in the low Q part on the structure factor S(Q) of Sn-1.8Cu tested under 320°C, but it disappeared finally when the testing temperature reached 350°C. The both viscosity was measured using a torsional oscillation viscometer. It was found that the anomalous variations of viscosity had a direct relation with the transition of the liquid structure, which is consonant with the results of high temperature X-ray diffraction. The microstructure of the solder matrixes as well as interfacial reaction between liquid solders and Cu substrates was also studied. The results show that particle-like Cu6Sn5 intermetallic compounds (IMCs) emerge in Sn-1.8Cu solder matrix. The IMC layer at Sn-1.8Cu/Cu joint is thicker than that at Sn-0.5Cu/Cu interface. The correlative effect of liquid structure on phase evolution in the solder joints is analyzed.



Advanced Materials Research (Volumes 97-101)

Edited by:

Zhengyi Jiang and Chunliang Zhang




X. M. Pan et al., "The Correlation between the Liquid Structure and the Viscosity of Sn-Cu Lead-Free Solders", Advanced Materials Research, Vols. 97-101, pp. 679-682, 2010

Online since:

March 2010




[1] Iida T and Guthrie R I L : The Physical Properties of Liquid Metals (Oxford: Clarendon Press 1993).

[2] Bian X F, Liu X F and Ma J J: Heredity of Cast Metals (Jinan: Shandong Technology Press1999) p.15.

[3] Brodley E, Bath J, Whitten G and Chada S:2000 Advanced Packaging Vol. 9(2000),P. 34.

[4] Frear D R, Jang J W, Lin J K and Zhang C JOM Vol. 53(2001), P. 28.

[5] Abtew M and Selvaduray G: Mater. Sci. and Eng. R Vol. 27(2000) 95.

[6] Waseda Y: The Structure of (on-Crystalline Materials (New York: McGraw-Gill 1980).

[7] Xue X Y, Bian X F, Geng H X and Qin X B: Mater. Sci. Eng. A Vol. 363(2003), P. 134.

[8] Bian X F, Min P X, Qin X B and Jiang M H: Sci. China (E) Vol. 45(2002) , P. 113.

[9] Qin J Y, Bian X F and Wang W M: Chin. Phys. Soc. Vol. 47 , (1998), P. 438 (in Chinese).

[10] Jürgen Brillo , Rob Brooks, Ivan Egry and Peter Quested. High Temperatures-High Pressures, Vol. 37(2008), 371-381.

Fetching data from Crossref.
This may take some time to load.