BAS, CMAS and CZAS glass coatings deposited by plasma spraying

In this study, three different industrial frits BaO–Al2O3–SiO2 (BAS), CaO–MgO–Al2O3–SiO2 (CMAS), CaO–ZrO2–Al2O3–SiO2 (CZAS) havebeen deposited on porcelainized stoneware tiles by plasma spraying. In the as-sprayed conditions, the microstructure of the coatings is defectivebecause of pores, microcracks and low intersplat cohesion. Hot stage microscope and differential thermal analysis measurements made on the glasspowders allowed to characterize the frits thermal behaviour. Post process thermal treatments have been arranged, following these indications as wellas preliminary tests, in order to achieve the lowest porosity and the highest resistance to abrasion. At the chosen temperatures, a microstructuralimprovement has been induced, but in the BAS specimens, an optimal sintering has not been accomplished because of the unavoidable fulloverlapping of the sintering and crystallization processes.