Melting temperature of a cone-shaped Sn needle

Abstract

The melting temperature of a needle-shaped single crystal of Sn has been measured as a function of the local size by an in-situ heating experiment in a transmission electron microscope. The results are analysed by a simple thermodynamic model and compared with those obtained by similar experiments on wedge-shaped films and particles.

Acknowledgments

This work was financially supported by the Japan Society for the Promotion of Science under Grant-in-Aid for Scientific Research A (Contact No. 14205092). J.C. would like to thank the Association of International Education Japan (AIEJ), Julie Marie Vinter Hansens Fund, Nordea Danmark Fund, Julie Damms Fund and Vordingborg Gymnasiums fund for financial support during this work. J.C. is grateful to Professor E. Johnson for many fruitful suggestions.

Notes

Detailed analysis of figure 2 may reveal that θ is not strictly 0. However, θ is unlikely to be larger than, say, 15°. Assuming that θ = 15°,

 = 0.966

. Thus, Δγ = 

 = −0.0340

. Thus, the condition for surface pre-melting Δγ > 0 is not satisfied, even if θ = 15°.