LAUSR

Abstract Amorphous phase is often detected in the plasma-sprayed LaMgAl11O19 (LMA) coating, the crystallization of which can cause the volume reduction of the coating, resulting in the failure of the coating. However, it is still not clear for the crystallization mechanism of the amorphous phase. In this paper, the coating samples were deposited using atmospheric plasma spraying. Adequate evidence showed that the crystallization of amorphous LMA occurred in two stages at about 900 and 1170 °C, respectively, by studying the phase transition of Al2O3 and the synthesis process of LMA. A novel crystallization mechanism on the amorphous LMA coating was also proposed. Results showed that highly charged La3+ in LMA magnetoplumbite structure controls the crystallization rate. The higher the La content in the composition the harder the crystallization occurs.