Mode Preparation And Thermal Isolation Effect Of Sm2zr2o7 Ceramics For Thermal Barrier Coatings

Material of Sm2Zr2O7 and (La0.5Sm0.5)(2)(Zr0.3Ce0.7)(2)O-7 powders were synthesized by the chemical coprecipitation method using Sm2O3, La2O3, Ce(NO3)(3)center dot 6H(2)O and ZrOCl2 center dot 8H(2)O powders as raw materials, and applied as ceramic topcoats of thermal barrier coating (TBC) by atmospheric plasma spraying (APS). Microstructure and phases of Sm2Zr2O7 powder and thermal barrier coatings were examined by scanning electrical microscopy and X-ray diffraction (XRD). The thermal isolation effect of coatings was evaluated by circular tube method under the same boundary conditions. The results show that the Sm2Zr2O7 and (La.Sm-0.5(0.5))(2)(Zr0.3Ce0.7)(2)O-7 ceramics powders prepared with solid sphere shape by spray-dried method are suitable for atmospheric plasma spraying. The thermal isolation effect of coatings are ordered in descending sequence as follows: LSZCO-TBCs, YSZ-TBCs, SZO-TBCs. Compared to SZO-TBCs and YSZ-TBCs, LSZCO-TBCs with coating thickness 0.3mm exhibits the thermal isolation from 10.3% to 28.7% due to the lower thermal conductivity in the condition of cooling flow 3 m(3)/h. The thermal conductivity of SZO material is reduced by 19.1% with doping La3+ and Ce4+ at A and B sites, respectively. In addition, the thermal isolation effect of coatings increases with the increasing of coating thickness and flow rate of cooling air. Compared with the flow rate of cooling air, thickness of coatings is more significant.