Application of image analysis for characterization of porosity in thermal spray coatings and correlation with small angle neutron scattering

Computational image analysis of Suspension Plasma Sprayed YSZ coatings

“…In general, many characterization techniques may be used for porosity analysis. The basic ones are [1,[9][10][11][12][13][14][15][16] The manner of porosity evaluation is classified differently by the literature [1,[17][18][19][20]. Two main approaches can be distinguished: (i) shape-based [1,[16][17][18], and (ii) size-related [1,16,17,20].…”

“…Deshpande et al [17] distinguishes three types of pores: globular, interlamellar and cracks. The same is proposed by Ganvir et al [1].…”

“…This assumption is consistent with the approach of Friis [20], which diversified pores into small and large groups (large were those of at least two splat thicknesses). Deshpande [17] evaluates the porosity in the subsequent limits: 3.0-10.0 µm for coarse globular pores, 0.1-3.0 µm for fine pores resulting from incomplete contact between lamellae during coating formation and 0.01-0.5 µm for fine cracks, derived from the relaxation of stresses occurred during splats cooling. The limitation of pore sizes depends on many factors.…”

“…Nevertheless, the great attention has to be paid to this technique [1,2,5]. The total coatings porosity (including both nano-and micropores) is of significant meaning: it affects the wide range of coating properties, such as: elastic modulus, thermal conductivity, dielectric behaviour and many others [3,5,15,17,22].…”

A Novel Image Segmentation Approach for Microstructure Modelling

“…Imaging methods were considered by Deshpande et al [8] who concluded back scattered SEM should be used with low electron energies for 2D models. This method has been used in the majority of studies since.…”