Abstract：To get the adhesion force Fa and the contact pressure Pc under different humid conditions for the microcontact of sphereflat pair, the theoretical calculations of van der Waals force FvdW and Laplace force FLap were carried out. Using the microcontact tests of SiO2/Si(100), the theoretical calculations of Fa under different humid conditions were verified. The results show that the adhesion force is mainly dominated by the van der Waals force under low humid conditions when less than one monolayer water film adsorbs on sample surface. The Laplace force gradually generates before the formation of continuous water film, and the adhesion force is raised with the increasing of relative humidity value. However, the adhesion force is dramatically decreased with reduced Laplace force under high humid conditions. Based on the contact theories of Hertz, DMT and JKR, the variation trend of the maximum contact pressure is similar with that of adhesion force under different humid conditions.
2019, Vol. 40 
