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

Abstract

• Hot corrosion products are different at temperatures ranging from 650 to 950 °C. • At 650 °C, the main corrosion products are AlVO 4 and NdVO 4 . • At 750 °C, V 2 O 5 reacts with NdMgAl 11 O 19 to form NdVO 4 , MgV 2 O 6 , AlVO 4 and alumina. • At 850 °C, the corrosion products consist of θ -Al 2 O 3 , NdVO 4 and MgAl 2 O 4 . • At 950 °C, the corrosion products are composed of α -Al 2 O 3 , NdVO 4 and MgAl 2 O 4 . 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 NdMgAl 11 O 19 ceramic by V 2 O 5 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 NdMgAl 11 O 19 ceramic by V 2 O 5 depend mainly upon corrosion temperatures. At 650 °C, the corrosion products are mainly composed of AlVO 4 and NdVO 4 . However, molten V 2 O 5 reacts with NdMgAl 11 O 19 to form NdVO 4 , MgV 2 O 6 , a small amount of AlVO 4 and alumina at 750 °C. At 850 °C, the corrosion products consist of θ -Al 2 O 3 , NdVO 4 and a small amount of MgAl 2 O 4 . After hot corrosion at 950 °C, the corrosion products are composed of α -Al 2 O 3 , NdVO 4 and MgAl 2 O 4 .