Microstructure and properties of CPED thermal protective ceramic coating toughened by ZrO₂ nanorods on Al–Si alloy

Abstract

In this study, ZrO 2 -Al 2 O 3 composite ceramic coating toughened by ZrO 2 nanorods through cathode plasma electrolytic deposition (CPED) was prepared on Al-Si alloy substrate. The microstructure, heat insulation performance, and fracture toughness of the coatings were investigated with SEM, XRD, heat insulation tests, and tensile tests. The ZrO 2 nanorods prepared by the hydrothermal method consist of monoclinic m-ZrO 2 and cubic c-ZrO 2 . The ZrO 2 nanorods are staggered in the ceramic coating and partially filled with plasma discharge micropores. The ZrO 2 -Al 2 O 3 ceramic coating, after adding zirconia nanorods, forms a high-temperature stable mixture of Zr 3 Y 4 O 12 , Al 2 O 3 , and ZrO 2 phases. The duration of hydrothermal during the preparation of ZrO 2 nanorods correlates with the heat insulation temperature of the toughened ceramic coating. The fracture toughness of ceramic coating toughened by ZrO 2 nanorods varies with hydrothermal duration, which can be effectively improved.

Corrosion resistance of modified YSZ coatings subjected to CMAS attacks

“…Moreover, CMAS melts actively react with the YSZ coating and partially dissolve it via the removal of yttrium ions. This removes Y 3+ from the solid solution and causes a phase transformation (t'-ZrO 2 → m-ZrO 2 ), which is accompanied by a 2-5% volume expansion that causes coating degradation [8][9][10]. Furthermore, with updated engine parameters in aeronautical systems, the temperature of the combustor has continuously increased, and corrosion of the TBC has become increasingly significant.…”