The impact of different measurement data filters on the characterization of porous surfaces

The surfaces of components can hold many different functional characteristics; those are strongly influenced by the surface texture, especially by the microstructure. That is to say, specifically functional micro structuring can minimize e.g. friction and wear and, therefore, can increase the endurance of components. In order to meet such functionality requests and thus the design of certain surface microstructures, an exact knowledge of the surface topography is required. In this study, the microstructures of thermally sprayed porous aluminium oxide surfaces are analyzed. To actually analyze the microstructure, the obtained surface measurement data, here acquired by a confocal laser scanning microscope, needs to be factorized by size. To do so, different surface filter techniques are applied. In this study the commonly used Total-Least-Square method and the Gaussian filter are compared to the wavelet transformation to separate the microstructure from form and waviness. The impact on the characterization of the porosity of the different filtering techniques is investigated.