Plasma-Sprayed Ceramic Coatings for SiAlON Ceramics

摘要

Plasma-sprayed coatings of yttria-stabilized ZrO_2 and Al_2O_3.TiO_2 used as a protective barrier on β-Si_3N_4-based sialon ceramics were investigated. The coatings showed better cohesion with the pre-oxidized surfaces due to the reaction between the SiO_2-rich oxidation layer and the coating materials. Formation of low thermal expansion zircon and aluminium titanate on the pre-oxidized ceramic was studied using scanning electron microscopy and X-ray diffraction. Preliminary experiments on oxidation and molten metal immersion, showed that the coatings provide significant protection against oxidation and molten metal attack.