Flammgespritzte Schichten im System Al2O3-TiO2-ZrO2

This work thoroughly investigates the phase development, microstructure development, and mechanical properties of flame-sprayed coatings. It presents the influence of composition and subsequent heat treatment on the respective fields. The most interesting result is the formation of an amorphous fraction in the sprayed state. This is attributed to the rapid cooling of the metastable system Al2O3, which tends to form glass. Crystallization processes caused by TiO2 and ZrO2 additives lead to the formation of primary and secondary amorphous fractions. The primary fractions exist as amorphous sub-layers within the structure, while the secondary fractions appear in a mixed dendritically shaped area. Both fractions significantly influence the mechanical properties. As the fractions increase, there is a rise in bending strength and the modulus of elasticity, along with a decrease in fracture elongation.