A Study of the Influence of Mounting Media on Quantitative Measurements of Thermal Spray Coatings

This study investigates the effect of mounting materials on microstructure and property measurements obtained from thermal spray coatings. Various epoxies and embedding techniques are used and a wide range of layers are examined, including HVOF sprayed WC-Co, Cr₃C₂-NiCr, and Al₂O₃-TiO₂; plasma sprayed Cr₂O₃, YSZ, WC-Co, and Ni-Al; and arc sprayed copper and silicon bronze. Image analysis measurements of area percent porosity, thickness, lamellar spacing, and unmelted particles and the results of hardness tests show substantial variation relative to the method used to encapsulate soft and porous coatings. Results indicate that the ideal mounting system for thermal spray coatings would consist of a low viscosity epoxy, to maximize penetration depth, and a high cured hardness, for adequate protection of surfaces and open porosity of hard coating materials. Paper includes a German-language abstract.