Preparation and characterization of rare earth modified nanocrystalline A1 ₂O ₃/13 wt%Ti0 ₂ feedstock for plasma spraying

The preparation and characterization of RE modified nanocrystalline A1 ₂0 ₃/13 wt%Ti0 ₂ feedstock for plasma spraying are described in this paper. Taking individual nano particles as starting materials, by wet ball milling, spray drying, sintering and plasma treating, nanocrystalline plasma sprayable feedstock is prepared. The as-prepared feedstocks were analyzed by XRD, SEM, EDS, TEM and HRTEM methods. As shown from analyses results, the reconstituted agglomerate feedstock possesses spherical geometry, proper particle size, homogeneous composition distribution and nano scaled grains. There are three dimensional net structures in the prepared feedstock, which could be retained in coatings if the feedstock does not melt or partially melts during the plasma spray process. The three dimensional net structures could play an important role in improving crack propagation resistance and wear resistance of coatings. The reconstitution process and characterization methods discussed in this paper can also be applied to prepare intraclass nanocrystalline feedstock such as Zr0 ₂/Y ₂O ₃ and Cr ₂0 ₃ et al.