Preparation and Characterization of LaMgAl_(11)O_(19) Used as Thermal Barrier Coat Materials

The LaMgAl11O19 ceramic was prepared by a two-step solid sintering method using aluminum hydroxide and lanthanum oxide and magnesium oxide as raw materials.The phase composition,microstructure,specific heat capacity,thermal expansion coefficient,thermal diffusivity,thermal expansion coefficient and thermal conductivity of the ceramic were investigated using X-ray diffractometer(XRD),scanning electron microscope(SEM),differential scanning calorimeter,dilatometry and laser flash method,respectively.The results showed that the main phase of the ceramic is hexagonal symmetry with plate-type structure over the range of RT～1200℃.As the temperature increases,the specific heat capacity of the ceramic is increased,the thermal diffusivity and thermal conductivity is decreased.The thermal conductivity of the material is superior to 6～8mol% yttria-partially-stabilized zirconia.