User manual LEICA STEREO EXPLORER APPLICATION NOTE

[. . . ] Leica StereoExplorer application note: Topography of thermally sprayed WC-Co-Cr coatings and their substrates - Comparison of Leica StereoExplorer and scanning Profilometer PROBLEM: To prevent errosion and corrosion of turbine rotor blades used in hydroelectric power plants, the blades can be covered by WC-Co-Cr coatings. Critical issues for a successful application of the coating are a well-defined substrate roughness to ensure a good coating adhesion and the correct determination of the coating thickness. [. . . ] To obtain reliable results using the StereoExplorer, in general an iterative procedure has to be apllied: Several images recorded with different magnifications and illuminations settings have to recorded and optimal parametres have to be defined by the operator. SAMPLES Sample 1: WC-Co-Cr coating sprayed on a sandblasted steel surface Figure 1 Figure 2 Figure 3 Sample 2: Grit-reblasted WC-Co-Cr coating inducing a step-structure Figure 4 Figure 5 RESULTS: An area of 1. 4mm x 1. 0mm has been imaged. Figure 2 indicates average roughness values for the for sample 1 and sample 2 obtained from a series of measurements at different sample locations. The obtained results with the Stereo Explorer agree well with values measured by a conventional scanning optical Profilometer. The average step height values measured on different locations on Sample 2 are shown in Figure 3. Addionally on 3 different surfaces of a Rugotest surface comparator the influence of the choosen magnification of the StereoExplorer has been checked. The planed and turned surfaces CN7, CN8 and CN9 feature a sinusoidal surface topography (see Figure 4). Figure 5 shows the average and the variation of the measured amplitudes of these sinusoidal structures measured with different magnifications (4 measurements for each magnification have been done). The dashed lines indicate the amplitude values as measured with a scanning laser Profilometer. Measurement time of StereoExplorer including experiment setup is typically about ten minutes and does not depend on data point density. [. . . ] It is obvious that the StereoExplorer values for surface roughness standards are in very good agreement with the laser Profilometer values and that the amplitudes do not depend on the choosen magnitude. The complete results of the project will be published in the Journal of Thermal Spray Technology Figure 2: Sa roughness values for samples 1 and 2 as determined by Stereo Explorer and a Scanning Optical Profilometer Figure 4: Measured line profile of the Rugotest CN9 surface Figure 3: Step height of the grit-reblasted coating of sample 2 as determined by Stereo Explorer and a Scanning Optical Profilometer Figure 5: Measured ampliutes of the sinusoidal structure for 3 Rugotest surfaces Leica Microsystems Ltd Business Unit SM CH-9435 Heerbrugg (Switzerland) Telephone +41 71 727 31 31 Fax +41 71 727 46 76 www. leica-microsystems. com Empa Materials Technology Laboratory Feuerwerkerstrasse 39 CH-3602 Thun (Switzerland) Telephone +41 33 228 46 26 www. empa. ch [. . . ]