Mathematical model and atomic force microscopy measurements of adhesion between graphite particles and rough walls

Abstract

The adhesion forces of particles on rough walls are important for particle–wall interactions in particle deposition, rebound, and resuspension. For the micron-scale graphite particles and sub-micron-scale rough walls in high-temperature gas-cooled reactors, a mathematical adhesion model is proposed based on the Johnson–Kendall–Roberts theoretical model and the assumption of asperity heights with Gaussian distribution. A statistical roughness parameter, the root-mean-square wall roughness height, is used to reflect the influence of roughness on adhesion. Meanwhile, an atomic force microscope (AFM) is used to measure the adhesion forces between different particles and rough walls, then the proposed model is verified based on related AFM measurements and compared with previous adhesion models. Although the AFM results exhibit considerable scatter, the statistical adhesion falls into the prediction range of the proposed model. The results show that the present model can explain the effects of material properties on adhesion and be extended to other AFM measurements. The present study provides a convenient and practical mathematical model for adhesion between particles and rough walls for engineering applications.