SELECTED THERMO-PHYSICAL PROPERTIES OF ZIRCONIA POWDERS BASED ON RARE EARTH ELEMENTS SUCH AS RE2Zr2O7 (RE - Gd, La, Sm, Nd) FOR THERMAL SPRAY COATING OF BARRIER LAYERS

Paper presents results of investigations of selected thermophysical properties of ceramics powders RE₂Zr₂O₇ (RE - Gd, La, Nd, Sm) type, used for thermal spray coatings. In comparison also standard powder of ZrO₂-8%wg. Y₂O₃ (Y8SZ) was tested. Using laser-flash method thermal conductivity was designated and specific heat c_p by differential scanning calorimetry (DSC) was determined. Measuring temperature varried from 25-1500ºC. The samples tested were sintered at 1000ºC. As a results of tests we obtain that thermal conductivity of RE₂Zr₂O₇ powders at 1000ºC is lower than Y8SZ. At temperature 25-750ºC higher thermal conductivity was observed for La₂Zr₂O₇ than for Y8SZ. The highest specific heat has zirconate powder Y8SZ, and the lowest- powder based on samarium zirconate.

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