Preparation of Rough Steel Surfaces

2 Basics and Experimental 7.2.1 Preparation of Rough Steel Surfaces 

A stochastically rough surface with a large diversity of spatial frequencies can be quantitatively described by Power Spectral Density (PSD) functions [9, 10]. The PSD function provides the relative strength of the individual roughness components as a function of the spatial frequencies f and f in 

X and directions, respectively. The PSD is defined as the squared absolute value of the Fourier Transform FT of the surface topography z(x,y) within a scan range L  

For surfaces with isotropic roughness characteristics, the PSD(f, fp can be simplified to a 2D-isotropic PSD by transforming into polar coordinates and averaging over all polar angles. By integration of the PSD, the root mean square roughness R is obtained. The R is the standard deviation of the surface topography data from the mean value. 

The wettability of an ideal solid surface (smooth, rigid, chemically homogeneous, insoluble, and nonreactive) depends only on the surface and interfacial tensions y. The relationship between the CA and the corresponding tensions is established by the Young theory [14]  

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