Influence of GdTaO4 doping concentration on thermophysical and mechanical properties of GdPO4/GdTaO4 composites

Tremendous efforts have been devoted to exploring alternative materials to 8 wt% yttria-stabilized zirconia used for thermal barrier coatings. In this work, novel composite ceramic GdPO4/GdTaO4 was designed by introducing GdTaO4 as second reinforcement phase into GdPO4 matrix. Mechanical and thermophysical properties of resulting composites were studied as a function of doping concentration of GdTaO4. Results suggested GdPO4/GdTaO4 composite ceramics consisting of GdPO4 monazite and GdTaO4 monoclinic phases, indicating GdPO4 and GdTaO4 with maintained excellent chemical compatibility at high temperatures. GdPO4/GdTaO4 composite ceramics achieved superior hardness of 5.82 GPa, fracture toughness of 2.72 MPa m(1/2), and thermal conductivity of 1.36 W center dot m(-1)center dot k(-1) at GT doping concentration of 50 wt% owing to grain refinement and scattering of phonons caused by the doped GdTaO4 phase. In sum, excellent mechanical and thermophysical properties of GdPO4/GdTaO4 composite ceramics look potential for thermal barrier coatings materials.

Automated summary

Novel composite ceramic GdPO4/GdTaO4 was designed by introducing GdTaO4 as second reinforcement phase into GdPO4 matrix. Results showed that GdPO4/GdTaO4 composite ceramics achieved excellent hardness, fracture toughness, and thermal conductivity at a doping concentration of 50 wt% due to grain refinement and scattering of phonons caused by the doped GdTaO4 phase. Therefore, GdPO4/GdTaO4 composite ceramics have potential as thermal barrier coatings materials.