Complex oxides for thermal barrier coating with reduced rare-earth contents and manufacturing method

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The present invention relates to low thermal conductive complex oxide ceramics for thermal barrier coating in a high temperature environment with reduced rare-earth elements, which is represented by Formula A_(2-x)Zr_2O_(7-1. 5x) (here, A is Gd, Sm or Dy; and 0 < x <= 1) and has a fluorite crystal structure, and a method for manufacturing the same. According to the present invention, the low thermal conductive complex oxide ceramics for thermal barrier coating in a high temperature environment has the following benefits : saving the manufacturing costs with reduced rare-earth elements which have problems of being expensive and unstable in supply and demand; achieving additional reduction in thermal conductivity by having a non-stoichiometric composition, wherein a vacancy with removed rare-earth elements acts as a point defect, which results in an increase in phonon scattering; and improving thermal expansion rate by increasing anharmonicity. Accordingly, reduced thermal conductivity and improved thermal expansion rate may be at the same or even in a higher level, compared with the existing materials (YSZ, stoichiometric rare-earth zirconate, etc.), thereby providing useful materials for high quality thermal barrier coating.