CMAS corrosion behavior of a LaPO 4 ceramic prepared by spark plasma sintering

Abstract At high temperatures in gas turbines, traditional yttria stabilized zirconia materials fail prematurely owing to CMAS (calcium–magnesium–alumina–silicate) corrosion. Thus, new materials need to be developed urgently. In this study, LaPO 4 powder was synthesized by chemical coprecipitation and heat treatment using lanthanum nitrate (La(NO 3 ) 3 ∙6H 2 O) and ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ) as starting materials, and LaPO 4 bulk was prepared by spark plasma sintering. The surface of the LaPO 4 bulk was coated with CMAS (CaO–MgO–Al 2 O 3 –SiO 2 ) powder, and the CMAS interaction with the LaPO 4 bulk at different temperatures was investigated. The phase and microstructure of the LaPO 4 powder and bulk, as well as the CMAS corrosion products, were characterized using X‐ray diffraction and scanning electron microscope. The superior CMAS resistance of the LaPO 4 bulk was attributed to the low wettability of LaPO 4 by the CMAS melt and the development of dense layers of new corrosion products, which effectively protected the LaPO 4 bulk from CMAS infiltration.