固体表面間の相互作用力に関する研究(第1報)

界面エネルギーの原子論的評価

抄録

This paper describes an estimation of interfacial surface energy γ0 from atomistic aspect and measurement of adhesion force, i. e. interaction between solid (Au, Ag, Cu) surfaces in an elastic contact condition in air. Assuming that chemical bonds occurs at the interface and the interatomic potential is Morse potential, surface energy and interface energy are calculated. The calculated surface energy of Au, Ag and Cu which is released at the interface between (111) and (100) lattice planes were 3.38, 2.69 and 4.20 J/m², respectively. The interaction force required to separate the contact between the tip and flat plane were theoretically estimated using the calculated γ₀. Then, the interaction force between the flat plane and the tip of radius 5-20 μm was measured by using a microelectrobalance. The contact pressure was controlled to be less than 2 μN in order to realize the elastic contact. The interfacial surface energy measured for Au, Ag and Cu were 1.57, 0.25 and 0.28 J/m², respectively. The values for Ag and Cu seemed to be consistent with van der Waals attraction. However, the value for Au was considerably large being 1.57 J/m² in spite of measurements in air, which was about 46% of atomistically calculated value. This suggests that the chemical bond (metallic bond) must be taken into consideration in the estimation of interfacial surface energy.