Hot corrosion behavior of neodymium magnesium hexaaluminate by vanadium pentoxide in air

• Hot corrosion products are different at temperatures ranging from 650 to 950 °C.
• At 650 °C, the main corrosion products are AlVO4 and NdVO4.
• At 750 °C, V2O5 reacts with NdMgAl11O19 to form NdVO4, MgV2O6, AlVO4 and alumina.
• At 850 °C, the corrosion products consist of θ-Al2O3, NdVO4 and MgAl2O4.
• At 950 °C, the corrosion products are composed of α-Al2O3, NdVO4 and MgAl2O4.

Hot corrosion due to molten salt attack is one of the main failure mechanisms of lanthanide magnesium hexaaluminate thermal barrier coating materials. Thermochemical attack of the NdMgAl11O19 ceramic by V2O5 was studied at different temperatures ranging from 650 to 950 °C using X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The corrosion products of the NdMgAl11O19 ceramic by V2O5 depend mainly upon corrosion temperatures. At 650 °C, the corrosion products are mainly composed of AlVO4 and NdVO4. However, molten V2O5 reacts with NdMgAl11O19 to form NdVO4, MgV2O6, a small amount of AlVO4 and alumina at 750 °C. At 850 °C, the corrosion products consist of θ-Al2O3, NdVO4 and a small amount of MgAl2O4. After hot corrosion at 950 °C, the corrosion products are composed of α-Al2O3, NdVO4 and MgAl2O4.