Microstructure and properties of in-situ ceramic matrix eutectic nanocomposite coating prepared by plasma spraying Al-Cr2O3-Al2O3 powder

According to the characteristic of eutectic solidification, the [Cr+(Cr,Al)2O3] eutectic nanocomposite coating was in-situ synthesized by reactive plasma spraying Al-Cr2O3-Al2O3 powder. The microstructure of the [Cr+(Cr,Al)2O3] coating shows the characteristic of nanostructure, in which Cr with granular and rod shape distributed homogeneously in (Cr,Al)2O3 matrix. The particle size of Cr was less than 10 nm, and the diameter of Cr with rod shape was less than 20 nm and the length of the rod was less than 100 nm. The microhardness of the [Cr+(Cr,Al)2O3] eutectic nanocomposite coating and the (Cr,Al)2O3 coating were HV0.3 1764 and HV0.3 1129, respectively. The toughness of the eutectic nanocomposite coating was higher than that of the (Cr,Al)2O3 coating. The wear resistance of the eutectic nanocomposite coating was 5.57 times of the (Cr,Al)2O3 coating.